Catad_tema Allergology - Articles

food allergy and food intolerance, terminology, classification, diagnostic and therapy problems

Luss Ludmila Vasilievna,
doctor medical sciences, professor, head of the scientific advisory department
SSC "Institute of Immunology of the Federal Medical and Biological Agency of Russia", Moscow.

FARMARUS PRINT
Moscow 2005

This manual is intended for allergists-immunologists, pediatricians, internists and doctors of other specialties.

It is difficult to find a person who during his life would not have some manifestations of food intolerance. As a rule, the first reactions associated with food intake are noted in childhood. In young children, such conditions are often called "exudative diathesis", even earlier they were called "scrofula", and later "allergy".

The problems of food allergy and food intolerance in recent decades have grown into a global medical and social problem. Currently, up to 30% of the world's population suffer from allergic diseases, among which food allergies occupy a significant part. Serious challenges face clinical allergology early diagnosis and therapy of food allergy, since in the early stages of the development of the disease, its clinical manifestations are nonspecific. The complexity of the problem lies in the fact that food intolerance can be caused by various mechanisms. So, food allergy can be the result of sensitization to food allergens, food additives, food impurities, etc., leading to the development of allergic inflammation, which is a qualitatively new form of response that arose at the late stages of human evolutionary development. In addition, the formation of food intolerance reactions may be due to the presence of comorbidities that lead to disruption of the processes of digestion and absorption of the food substrate.

An equally serious problem is the widespread introduction into human nutrition of qualitatively new products, genetically modified or altered, on the nature of their influence on the gastrointestinal tract, hepatobiliary and immune systems, there is no convincing data. Moreover, the study of adverse reactions to food can be considered as one of the critical issues national biosecurity.

In addition, the presence of cross-reacting properties between food and other groups of allergens creates conditions for expanding the range of causal allergens, the formation of polysensitization, the development of more severe forms of allergopathology and poor prognosis.

IN clinical practice, as a rule, the diagnosis of "food allergy" is made on the basis of a causal relationship between food intake and development clinical symptoms its intolerance, which is the cause of disagreement in the interpretation of the very concept of food allergy and incorrect diagnosis.

It should be noted that food allergy is only a part of the many reactions that make up the definition: "increased sensitivity to food." "Hypersensitivity to food" - includes reactions of food intolerance, different in the mechanism of development, clinical symptoms and prognosis. The most common are food intolerances, food allergies, and food aversions.

Food hypersensitivity reactions have been known for a long time. Hippocrates first described severe reactions to cow's milk in the form of gastrointestinal and skin manifestations. Galen reported allergic-like reactions in children after drinking goat's milk. In the 17th and 18th centuries, many observations of severe adverse reactions to food were presented: asthma attacks after eating fish, skin manifestations after eating eggs or crustaceans (oysters, crabs).

Already in 1656, Pierre Borel (in France) first used skin tests with egg white.

In 1902, Richet and his colleagues first described food anaphylaxis, and in 1905 Schlosmann, and a few years later Finkelstein, reported cases of anaphylactic shock after drinking milk. Later, oral specific immunotherapy was first proposed.

A significant contribution to understanding the problem of food allergy, in the early thirties of the XX century, was made by Rowe in the United States, designating it as the most important medical problem.

Epidemiology

To date, there is no accurate epidemiological data on the prevalence of food allergies. This is due to many factors: the lack of unified diagnostic criteria, the long-term absence of a unified classification and the associated under- and overdiagnosis, the presence of a large number of potential food allergens, frequent presence in food "hidden food" allergen, the appearance in last years genetically modified food and the lack of information about its impact on the course and occurrence of food allergies.

However, it is clear that food allergies usually occur in children under 15 years of age.

The frequency of occurrence of food allergies is expressed as a ratio of 3 children per 1 adult. It is known that in childhood food allergies are detected in girls approximately 7 times more often than in boys.

Animal food allergies are more common in children under 6 years of age, and food allergies plant origin most often occurs over the age of 6 years and in adults.

According to domestic and foreign researchers, the prevalence of food allergies varies widely from 0.01 to 50%. In particular, it is believed that food allergies occur on average in 10% of children and 2% of adults. In 30-40% of children and 20% of adults suffering from atopic dermatitis, exacerbations of the disease are associated with food allergies. Among patients with bronchial asthma (without dividing it into separate forms), in 8% of cases asthma attacks were caused by food allergies, and in the group of patients with atopy, the relationship between exacerbation of the disease and food allergens reaches 17%. Among patients with diseases gastrointestinal tract and the hepatobiliary system, the prevalence of food allergy is higher than among people who do not suffer from this pathology, and ranges from 5 to 50%. (A.M. Nogaller, 1983).

According to the scientific advisory department of the Institute of Immunology of the Federal Medical and Biological Agency of Russia, 65% of patients suffering from allergic diseases indicate food intolerance. Of these, true allergic reactions to food allergens are detected in approximately 35%, and pseudo-allergic reactions in 65%. According to the data of appeals to this department, true food allergy as the main allergic disease in the structure of all allergic pathology over the past 5 years accounted for about 5.5%, reactions to impurities found in food products - 0.9%. Allergic reactions to food were observed in 48% of patients with atopic dermatitis, 45% of patients with hay fever, 15% of patients with bronchial asthma and 15% of patients with allergic rhinitis.

Etiology. Almost any food product can become an allergen and cause the development of food allergies. However, some food products have pronounced allergenic properties, while others have a weak sensitizing activity. Protein products containing animal and vegetable proteins have more pronounced sensitizing properties, although there is no direct relationship between the protein content and the allergenicity of products. The most common food allergens include milk, fish and fish products, eggs, meat of various animals and birds, food cereals, legumes, nuts, vegetables and fruits, and others.

Fish and seafood. Fish and seafood are among the most common food allergens. In fish, the most allergenic are sarcoplasmic proteins - parvalbumin. The cod M-protein has the most pronounced allergenic properties, which has thermal stability; when boiled, it turns into a steam distillate and is stored in odors and vapors. It is believed that sea fish is more allergenic than river fish.

Seafood with pronounced allergenic properties includes crustaceans (shrimp, crabs, crayfish, lobsters), shellfish (mussels, oysters, sponges, lobster, squid, octopus), etc.

A muscle allergen, tropomyasin, has been isolated from shrimp (it is also found in other crustaceans and molluscs). Tropomyasin persists in the water where the shrimp has been boiled. Shellfish tropomyasins have not been well studied, but all tropomyasins are known to be resistant to processing and action of digestive juices.

Milk. The main milk proteins that have sensitizing activity and are of great practical importance are: a-lactalbumin, which makes up 4% of cow's milk protein antigens.

a-lactalbumin it is thermolabile, turns into foam when boiled, species-specific, has cross-linking determinants with egg protein (ovalbumin).

b-lactoglobulin, makes up to 10% of cow's milk proteins. It has the highest allergenic activity, is species-specific, thermostable, and is practically absent in humans.

Casein among the proteins of cow's milk is up to 80%, the protein is nonspecific, thermostable, stable in the acidic environment of gastric juice, precipitates when acidified, especially a lot of casein in cottage cheese, in cheeses.

Bovine serum albumin found in milk in trace amounts, thermostable, cross-reacts with beef and veal.

The milk of other mammals also has allergenic properties. Goat milk also has pronounced allergenic properties.

Egg protein, like fish proteins, are among the most common etiologically significant food allergens. Among egg proteins, ovalbumin, ovamucoid, and conalbumin have the most pronounced allergenic properties. Ovalbumin makes up 64% of egg proteins and is thermolabile. In animals (rats) it causes an anaphylactoid reaction due to the ability of nonspecific histamine release from mast cells. Ovamucoid is contained in the egg up to 9%, has thermal stability, inhibits trypsin and therefore remains in the intestine for a long time. Ovamucoid is often the cause of the development of pseudo-allergic reactions to the egg due to the ability to cause nonspecific histamine release.

Conalbumin in the egg contains 14%, this protein cross-reacts with feathers and bird droppings. The egg also contains lysozyme (34%) and ovoglobulin (9%).

The main allergen of the yolk is a-livetin, which has a pronounced cross-reactivity with feathers and bird droppings.

animal meat. Allergy to animal meat is rare, most allergenic animal meat proteins completely lose their sensitizing activity after thermal and culinary treatment. Allergic reactions can be observed both to one type of meat (beef, pork, lamb), and to the meat of animals of different species.

There are two main allergens in animal meat: serum albumin and gamma globulin.

Food Grains: wheat, rye, barley, corn, rice, millet (millet), cane, bamboo. The main allergens of food cereals are albumin and globulin.

Buckwheat family: buckwheat, rhubarb, sorrel. Buckwheat belongs to the "pseudo-cereals".

In Europe, buckwheat is used as an alternative food for patients who are allergic to food grains. However, in Japan, buckwheat is one of the most common food allergens due to the consumption of large amounts of buckwheat noodles.

Nightshade: tomato, potato, eggplant, Bell pepper. Tomato is rich in histamine.

Umbrella: celery, carrots, parsley, dill, fennel, coriander, cumin, anise.

Celery contains a thermostable allergen and heat treatment does not lose its sensitizing properties.

Rosaceae: apples, peaches, apricots, plums, cherries, raspberries. Monoallergy to Rosaceae is rare. Allergy to Rosaceae is more common in patients with hay fever, sensitized to tree pollen.

Nuts: hazelnuts, brazil nuts, cashews, pecans, pistachios, almonds, coconut, pine nuts, walnuts. Nuts are food allergens with a pronounced sensitizing activity and the presence of cross-reactions with other groups of allergens.

Sesame, poppy, sunflower seeds ("seeds") can also cause severe allergic reactions.

Legumes: soybeans, peanuts, peas, lentils, beans, lupins. It was previously believed that allergies to legumes, especially soybeans, were relatively rare, but in recent years there has been a significant increase in food allergies to this product, due to a significant increase in the consumption of soybeans with food in children and adults.

Peanut It has the strongest allergenic properties among legumes, causing severe allergic reactions, up to anaphylactic shock. Peanuts are widely used in the food industry and are among the so-called "hidden allergens".

According to epidemiological studies, there is a trend towards an increase in the number of allergic reactions to peanuts. When cooking and frying, the allergenic properties of peanuts are enhanced.

Soya It is widely used in the food industry and is a commonly used food product among the population, especially among vegetarians.

Cross-properties between food and other allergen groups

One of serious problems food allergy is the presence of cross-allergenic properties between food and other non-infectious and infectious allergens.

It is known that the main sources of plant food allergens that are important in the formation of food allergies are: PR (pathogen-response proteins) proteins or "protection proteins", actin-binding (structural) proteins or profilins, thiol proteases and prolamins (seed reserve proteins). and storage/reserve proteins). PR proteins have a rather low molecular weight, are stable at low pH values, are resistant to the action of proteases, and have structural commonality. Of the 14 groups of PR proteins, 8 contain allergens that cross-react with various food products and are of great practical importance. Thus, PR2 proteins (β-1,3,-gluconases) isolated from the Brazilian Hevea (Hev b 2) have cross-reactivity with many vegetables and fruits and are the cause of the fruit-latex syndrome.

PR3 proteins (endochitinases) hydrolyze chitin and have cross properties with latex, fruits, and vegetables. PR4 proteins (chitinases) have amino acid sequences homologous to soy, potato, and tomato proteins.

PR5 proteins (thaumatin-like proteins), the first of them isolated main allergen apples, cherries, mountain cedar pollen. The amino acid sequence of this allergen is homologous to thaumatin in wheat, sweet peppers, and tomatoes. PR8 proteins (latex minor allergen hevamin) are identical to cucumber lysozyme/chitinase. PR9 proteins (lignin-forming peroxidases) isolated from wheat flour are considered to be the cause of "bakery's asthma". PR10 proteins are a large group of intracellular proteins from plants of different families (drupaceous, solanaceous, etc.). Structural homology is observed with birch, alder, hazel, chestnut, hornbeam, oak and food products (chestnut, hazelnut, acorn, etc.) allergens. PR14 proteins provide intermembrane transfer of phospholipids from liposomes to mitochondria. PR14 proteins have a pronounced cross-reactivity. The first PR14 proteins were isolated from nettle pollen, they include such allergens: peaches, apricots, plums, cherries, apples, grapes, hazelnut, chestnut.

Actin-binding (structural) proteins or profilins

Actin-binding (structural) proteins regulate the network of actin fibers that form the plant cytoskeleton. These proteins were first discovered in birch pollen and named profilins. They have pronounced cross-reactive properties with many groups of allergens and are often the cause of anaphylactic reactions, especially in children, to soy and peanuts. Profimens are associated with the development of allergic reactions to carrots, potatoes, celery, pumpkin seeds, hazelnuts, tomatoes, etc. in patients with hay fever.

Thiol proteases contain papain from papaya, ficin from fig berry, bromelain from pineapple, actinidin from kiwi, soy protein from soy.

Prolamins are seed reserve proteins and storage/reserve proteins. Many seed storage proteins are PR14 proteins.

The presence of cross-reactions between proteins contained in different foods is especially important for patients with IPA, since these patients may develop allergic cross-reactions to other groups of allergens, such as pollen (Table 1). Food grains cause cross-reactions with grass pollen. Banana has cross properties with avocado, melon and wormwood pollen. Soy is cross-reactive with milk casein (about 15% of children with cow's milk allergy are cross-sensitized to soy). Peanuts are cross-reactive with soy and potatoes. After roasting and boiling, the allergenic properties of peanuts are enhanced. Peanuts, hazelnuts, walnuts are not recommended for patients with allergies to Compositae.

Table 1. Cross-reactions between food and pollen allergens

Cross-reactions can also develop between food, household and epidermal allergens (Table 2).

Table 2. Cross-reactions between food, household and epidermal allergens

Pork has cross-allergenic properties with cat hair and cat serum albumin, which lead to the development of the so-called pork-cat syndrome in patients.

Allergens of crustaceans and mollusks have cross-reactivity. There is also cross-reactivity between fish allergens of different species.

Cross-reactions between goat and cow milk proteins are possible. Mare's milk also has cross-reactivity with various types of milk - cow, goat, sheep. Sensitization to mare's milk proteins may occur in patients with sensitization to horse hair (horse dander). Ovamucoid has cross-reactive properties with the serum of beef, horse, mouse, rat, rabbit, cat, dog.

If you are allergic to egg proteins, you may experience an increased sensitivity to meat. various kinds birds, as well as to bird feathers and droppings, the so-called virdegg syndrome.

There is a moderately pronounced cross-reactivity between the meat of chicken, goose, pigeon, turkey, quail and blood serum of beef, horse, mouse, rat, dog, cat, rabbit.

It is known that in the presence of a true food allergy to coffee and cocoa, cross-allergic reactions often develop with the use of other legumes (beans, peas, lentils, etc.).

Kiwi has cross-reactions with various food and pollen allergens (Fig. 1).

Rice. 1. Most Common Kiwi Cross Reactions

In practical medicine, the possibility of developing cross-allergic reactions to serum preparations obtained from animals whose meat is allergic is important, for example, the development of a reaction to the administration of antidiphtheria serum in case of allergy to horse meat, or to enzyme preparations obtained from the pancreas and intestinal mucosa cattle, pigs, etc.

Classification

There is no generally accepted unified classification of food allergies. In the classification of adverse reactions to food taken abroad, food allergies include completely different food intolerance reactions according to the mechanisms of development: true food allergy; food pseudo-allergy, or false food allergy; food intolerance; toxic food reactions; anaphylactic shock.

It is obvious that such an approach to the terminology of food allergy creates a number of problems in determining the tactics of managing patients with food intolerance, which are so different in pathogenesis.

At the congress of the European Academy of Allergy and Clinical Immunology (Stockholm, June 1994), a working classification of adverse reactions to food was proposed, which is based on the mechanisms of development of these reactions (Fig. 2). According to this classification, among food intolerance reactions, reactions to food of a toxic and non-toxic nature are distinguished. Non-toxic reactions to food can be the result of both immune and non-immune mechanisms.

Rice. 2. Classification of adverse reactions to food
(European Academy of Allergy and Clinical Immunology, Stockholm. 1994)

It should be noted that Academician of the Russian Academy of Medical Sciences A.D. Back in the 60s of the twentieth century, Ado pointed out that, according to the mechanism of development, allergic reactions are divided into true and false. This also applies to food allergies, in which true allergic reactions to food (food allergy) and pseudo-allergic (food intolerance) are distinguished. The same positions are formulated in the classification of food intolerance adopted in Stockholm (1994).

From a pathophysiological standpoint, food allergy should include food intolerance reactions, the development of which is based on immunological mechanisms. They can proceed through both humoral and cellular mechanisms of allergy, i.e. with the participation of allergic antibodies or sensitized lymphocytes. Immunologically mediated true food allergy, depending on the mechanism, is divided into IgE and non-IgE-mediated reactions and food allergy, proceeding through the mechanisms of delayed allergy.

Non-immunological food intolerance of a non-toxic nature may be due to the presence of congenital and acquired enzymopathies (for example, intolerance to cow's milk due to lactase deficiency), the presence of pharmacological and other impurities in foods. Secondary lactase deficiency occurs mainly in adults, while most other enzyme deficiencies are rare inborn errors of metabolism.

Enzymopathies are one of the most important causes of food intolerance, which lead to metabolic and absorption disorders (carbohydrates, proteins and fats), clinically manifested by various pathological symptoms.

Some patients who claim to be allergic to food, despite their lack of objective data, may need psychological help and medical examination by a psychiatrist.

Toxic reactions develop after eating foods containing toxic substances as impurities. The clinical manifestations of these reactions and their severity depend on the dose and chemical properties of toxic compounds, and not on the type of food product. Toxic contaminants in food can be a natural component of food or formed during the cooking process, or ingested through contamination, or through the toxic effects of food additives.

Natural food components include natural toxins (for example, cyanides), which are found in mushrooms, fruits, berries, fruit pits (compote from cherries with pits, from apricots with pits).

Toxins produced during cooking include, for example, hemagglutinins, which are found in undercooked beans. Molds that affect cheeses, cereals, cereals, soybeans contain aflatoxin, which causes severe adverse reactions after consumption of such products.

An example of toxins that can be ingested when contaminated food is algae toxins, which feed on fish, shellfish and crustaceans. These algae contain PSP (paralytic shellfish poisoning) toxin and DSP (diarrhetic shellfish poisoning) toxin, which are responsible for the development of severe systemic non-immunological reactions, which can be mistakenly attributed to allergic reactions to fish and seafood.

Toxic reactions can be observed when eating foods with an excess content of nitrates, nitrites, sulfates.

In addition, toxic reactions to food may develop due to the presence of toxins or bacteria in the food that are responsible for histamine shock (eg, histamine released from fish poisoning), or chemical impurities in food may provoke certain disorders (eg, caffeine in coffee).

Factors contributing to the formation of food allergies are common for adults and children.

At normal functioning gastrointestinal (GIT) and hepatobiliary system, sensitization to food products supplied by the enteral route does not develop.

Genetically determined predisposition to allergies is of great importance in the formation of food sensitization. Studies have shown that about half of patients suffering from food allergies have a burdened family or their own allergic history, i.e. either they themselves suffer from any allergic diseases (hay fever, atopic bronchial asthma), or their closest relatives suffer from these diseases.

The formation of food allergies contributes to maternal malnutrition during pregnancy and lactation (abuse of certain foods that have a pronounced sensitizing activity: fish, eggs, nuts, milk, etc.). The provoking factors in the development of food allergies are the following: early transfer of the child to artificial feeding; malnutrition of children, expressed in a discrepancy between the volume and ratio of food ingredients to the body weight and age of the child; concomitant diseases of the gastrointestinal tract, diseases of the liver and biliary tract, etc.

Normal digestion and absorption of food products is ensured by the state of the neuroendocrine system, the structure and function of the gastrointestinal tract, the hepatobiliary system, the composition and volume of digestive juices, the composition of the intestinal microflora, the state of local immunity of the intestinal mucosa (lymphoid tissue, secretory immunoglobulins, etc.) and other factors.

Normally, food products are broken down to compounds that do not have sensitizing properties (amino acids and other non-antigenic structures), and the intestinal wall is impermeable to non-digested products that have or may have, under certain conditions, sensitizing activity or the ability to cause pseudo-allergic reactions.

An increase in the permeability of the intestinal mucosa, which is noted in inflammatory diseases of the gastrointestinal tract, contributes to excessive absorption of unsplit products that can sensitize the body or cause pseudo-allergic reactions.

Violation (decrease or acceleration) of the absorption of macromolecular compounds may be due to a violation of the stages of transformation of the food substrate in the digestive tract with insufficient pancreatic function, enzymopathy, dyskinesia of the biliary tract and intestines, etc.

Disorderly eating, rare or frequent meals lead to a violation of the secretion of the stomach, the development of gastritis, mucus hypersecretion and other disorders that contribute to the formation of food allergies or pseudo-allergies.

The formation of hypersensitivity to foods of a protein nature is influenced not only by the amount of food taken and diet violations, but also by the acidity of gastric juice (A. Ugolev, 1985). In experimental studies, it was found that with an increase in the acidity of gastric juice, the absorption of undigested proteins decreases. It has been shown that a lack of calcium salts in food contributes to an increase in the absorption of undigested proteins.

Various researchers, using various research methods (electron microscopic, histochemical, histological, etc.), found metabolic disorders, a decrease in enzymatic activity, an increase in the permeability of the mucous membrane of the digestive tract in 40-100% of the examined patients with food allergies (A.M. Nogaller, 1983; M. Lessof et al., 1986).

Immune mechanisms of food allergy development

The information obtained in recent years has made it possible to specify some ideas about the mechanisms of the formation of food intolerance, but so far the mechanisms of the formation of true food allergy have not been studied enough. Sensitization to food allergens can occur in utero, in infancy and early childhood, in children and adolescents, or in adults.

Maternal allergen-specific IgE do not cross the placental barrier, but it is known that the fetus can produce such antibodies as early as 11 weeks.

It is assumed that maternal antibodies belonging to IgG play a major role in the transmission of the allergen to the fetus. These antibodies cross the placental barrier, carrying the food allergen as part of the immune complex.

Transmission of the allergen to the fetus is also possible through the amniotic fluid, through the highly permeable skin of the fetus, through the swallowing movements of the fetus, and due to the entry of the antigen into the intestines or into the airways during the respiratory movements of the fetus.

To date, data have been obtained on the existence in all newborns of a universal propensity for the initial response of T-lymphocytes towards the Th2 cytokine profile and the synthesis of interleukin (IL)-4 and the relative insufficiency of the production of interferon-γ (IFN-γ). Sensitization to food allergens often develops in infancy in both atopic and non-atopic patients. It was found that in non-atopics, the peak concentration of allergen-specific IgE to food allergens is usually observed during the first year of life, and then decreases, and further IgE to food allergens is not detected.

In children with atopic diseases, the titer of allergen-specific IgE to foods is constantly maintained and grows (often very high). There is evidence that the presence of a high titer of allergen-specific IgE to chicken protein in young children, it is a marker that allows predicting the development of atopic disease in the future.

True allergic reactions to food are based on sensitization and immune response to repeated exposure to a food allergen.

The food allergy developing according to the mechanisms of type I (IgE-mediated) is the most studied. For the formation of a food allergy, a food allergen must be able to induce the function of T-helpers and inhibit the activity of T-suppressors, which leads to increased production of IgE. In addition, the allergen must have at least two identical determinants separated from each other, binding receptors on target cells, followed by the release of allergy mediators.

Along with IgE, antibodies of the IgG4 class are essential in the mechanism of food allergy development, especially in case of allergy to milk, eggs, and fish.

Sometimes food allergies can develop to certain food additives, especially azo dyes (eg tartrazine). In this case, the latter act as haptens, and forming complexes with a protein, for example, with serum albumin, they become a full-fledged antigen, for which antibodies are produced in the body.

The existence of IgE antibodies against tartrazine has been demonstrated in animal experiments, and they were detected in humans using RAST.

It is also possible to develop delayed-type hypersensitivity, manifested in the form of eczema, with the use of foods containing azo dyes, benzylhydrooxytoluene, butylhydroxyanisole, quinine, etc. In particular, it has been found that food additives can induce the production of a factor that inhibits the migration of macrophages, which is a mediator of delayed-type hypersensitivity , which indicates the development of delayed allergic reactions to food products containing these additives.

However, it should be noted that, in a double-blind placebo-controlled study (DBPCFCs), the decisive role of immunoglobulin isotypes (except IgE) of immune complexes and cell-mediated reactions in the mechanism of food reaction has not been proven with sufficient conclusiveness.

False allergic reactions to food (pseudoallergy)

More often, food intolerance proceeds through the mechanisms of pseudo-allergic reactions (PAR). PAR and true allergic reactions have similar clinical manifestations, but different mechanisms of development. PAR to food does not involve specific immune mechanisms as in true food allergy. The development of PAR on food products is based on the nonspecific release of mediators (mainly histamine) from allergy target cells.

PAR differ from other food intolerance reactions in that although the same mediators are involved in their development as in true food allergies (histamine, leukotrienes, prostaglandins, other cytokines, etc.), they are released from allergy target cells in a non-immunological way. This is possible with the direct action of food product proteins (without the participation of allergic antibodies) on target cells (mast cells, in particular) and indirectly, with the activation of a number of biological systems by an antigen (kinin, complement systems, etc.). Among the mediators responsible for the development of intolerance symptoms in PAR, a special role is assigned to histamine.

A number of factors contribute to the development of PAR on food products: excessive intake of histamine in the body; when using (abusing) foods rich in histamine, tyramine, histamine liberators; excessive formation of histamine and / or tyramine from the food substrate due to the synthesis of their intestinal flora; increased absorption of histamine and / or tyramine with functional insufficiency of the gastrointestinal mucosa; excessive formation of tyramine with a partial deficiency of platelet monoamine oxidase, which leads to incomplete destruction of endogenous tyramine; increased release of histamine from target cells; violation of the synthesis of prostaglandins, leukotrienes.

Most often, PAR develop after eating foods rich in histamine, tyramine, histamine liberators, such as fermented cheeses, sauerkraut, dried ham and beef sausages, fermented wines, pork liver, canned tuna, herring fillet, canned smoked herring caviar, spinach, tomatoes, industrial Roquefort, camembert, brie, cheddar, brewer's yeast, pickled herring, etc.

An example of the development of PAR on fish products is the consumption of fish with a high content of red meat, which turns brown when cooked (family Scambridae - tuna, mackerel, mackerel) and contains in muscle tissue a large number of histidine. When fish is stored incorrectly, cooled or frozen in violation of the technology of this process, histidine, under the influence of bacterial histidine decarboxylase, passes into histamine. A very large amount of histamine, the so-called scombrotoxin, is formed, which causes scombrotoxic poisoning, symptomatically similar to an allergic reaction: skin redness, urticaria, vomiting, abdominal pain, diarrhea. Due to the very high content of histamine, scombrotoxin is inactivated during heat treatment (during cooking, smoking) and salting.

In recent years, there has been an increase in PAR for impurities with high physical and biological activity (pesticides, fluorine-containing, organochlorine compounds, sulfur compounds, acid aerosols, products of the microbiological industry, etc.) that contaminate food products.

Often the reason for the development of PAR on food products is not the product itself, but various chemical additives introduced to improve taste, smell, color, and ensure long-term storage. Food additives include a large group of substances: dyes, flavors, antioxidants, emulsifiers, enzymes, thickeners, bacteriostatic substances, preservatives, etc. The most common food dyes include tartrazine, which provides an orange-yellow color to the product; sodium nitrite, which preserves the red color of meat products, etc.

Monosodium glutamate, salicylates, in particular, acetylsalicylic acid, etc. are used to preserve food.

Vasoactive amine - betaphenylethylamine, which is found in chocolate, in products subjected to fermentation, for example, cheeses, fermented cocoa beans. Such products cause symptoms in patients similar to reactions that occur with allergies.

The most common nutritional supplements

Food colorings: tartrazine (E102), yellow-orange (E110), erythrosin (E-127), azorubine (E-122), amaranth (E-123), cochineal red (E-124), brilliant black BN (E-151) .

Preservatives: benzoic acid (E-210), benzoates (E 211-219), sulfites and their derivatives (E 220-227), nitrites (E 249-252).

Flavoring additives: monosodium glutamate (E-621), potassium glutamate (E-622), calcium glutamate (E-623), ammonium glutamate (E-624), magnesium glutamate (E-625).

Flavors: glutamates (B 550-553).

Products containing sulfites: salads of tomatoes, carrots, peppers, onions, vinegar, marinades and pickles, fruit juices, wine, beer, liqueurs, liqueurs, gelatin, dried vegetables, minced meat, cheeses, sauces for meat, fish, canned vegetables, soups, dry soup mixes, seafood, fresh fish, baking mixes.

Foods that may contain tartrazine: fried crispy potatoes dyed orange, ready-made pies, gingerbread, puddings, icing, frozen baked goods, instant dough bread, chocolate chips, ready-made dough mixes, colored soda and fruit drinks, colored marshmallows, caramel, dragee, candy wrapper, cereal.

The mechanism of action of food impurities and food additives can be different:
- induction of PAR due to the direct action of drugs on sensitive target cells of allergy, followed by non-specific liberation of mediators (histamine);
- metabolic disorders arachidonic acid(tartrazine, acetylsalicylic acid) due to the inhibition of cyclooxygenase and imbalance in the direction of the predominant formation of leukotrienes, which have a pronounced biological effect on various tissues and systems, causing smooth muscle spasm (bronchospasm), mucus hypersecretion, increased vascular wall permeability, a decrease in coronary blood flow and others;
- activation of complement along an alternative pathway by a number of food additives, while complement activation products have an effect similar to the action of allergy mediators;
- inhibition of the enzymatic activity of monoamine oxidase.

It should be noted that the presence of a true food allergy does not exclude the occurrence of false allergic reactions to food products in the same patient.

Until now, while there are no convincing data on the safety of genetically modified foods, they should not be consumed by patients with food allergies. Genetically processed (modified) food - qualitatively new products obtained by genetic processing (soybeans, potatoes, corn, etc.) using modern new technologies. The effect of genetically modified products on the body and human enzyme systems has not been studied enough.

Clinical manifestations of food allergy

The clinical symptoms of food intolerance, whether caused by sensitization or other mechanisms, are varied in form, location, severity, and prognosis, but none of the symptoms is specific to food allergy.

There are systemic allergic reactions after exposure to a food allergen and local ones. Systemic allergic reactions to food can develop and occur with a primary lesion of various organs and systems. The earliest and most typical manifestation of a true food allergy is the development of oral allergy syndrome (OSA).

OSA is characterized by the appearance of perioral dermatitis, itching in the mouth, numbness and / or a feeling of "bursting" of the tongue, hard and / or soft palate, swelling of the oral mucosa after the use of the "guilty" food allergen.

The most severe manifestation of a true food allergy is anaphylactic shock, which develops after eating (swallowing) food products, such as fish, eggs, milk, peanuts (peanuts), etc.

Anaphylactic shock with a true food allergy, it can occur within an interval of several seconds to 4 hours after a meal, it is characterized by a severe course, serious forecast(mortality in anaphylactic shock ranges from 20 to 70%).

With PAR on food, systemic reactions can manifest as anaphylactoid shock.

Anaphylactoid shock caused by the use of a food product develops according to the mechanisms of pseudo-allergy; according to clinical symptoms, it may resemble anaphylactic shock, but differs from the latter in the absence of polysyndromicity and a more favorable prognosis. In particular, with anaphylactoid shock, symptoms are observed mainly from one of the body systems, for example, a drop in blood pressure (BP) and loss of consciousness. In the case of an anaphylactic reaction in the form of generalized urticaria and Quincke's edema, there is a sharp weakness, nausea, but blood pressure remains within normal values. The prognosis for anaphylactoid shock is favorable, and with the timely appointment of adequate symptomatic therapy, a positive clinical effect occurs quickly, usually in the first minutes and hours after the start of therapy.

Gastrointestinal manifestations of food allergy. The most common clinical manifestations of food allergy in the gastrointestinal tract include: vomiting, colic, anorexia, constipation, diarrhea, allergic enterocolitis.

Vomit with food allergies, it can occur from several minutes to 4-6 hours after a meal. Sometimes vomiting takes on a stubborn character, simulating acetonemic. The occurrence of vomiting is associated mainly with the spastic pyloric reaction when a food allergen enters the stomach.

Colic. Allergic colicky abdominal pain can occur immediately after a meal or several hours later and be due to spasm of the smooth muscles of the intestine associated with specific or nonspecific liberation of allergy mediators. Pain in the abdomen is usually intense and in some cases forced to consult a surgeon. Pain in the abdomen with food allergies may not be as intense, but constant and accompanied by a decrease in appetite, the appearance of mucus in the stool and other dyspeptic disorders.

Anorexia. In some cases, the lack of appetite in food allergies may be selective in relation to the causative food allergen, in others there is a general decrease in appetite.

constipation with food allergies due to spasm of smooth muscles in different parts of the intestine. With X-ray contrast studies, as a rule, it is possible to well determine areas of the spasmodic intestine.

Diarrhea. Frequent, loose stools following ingestion of a causative food allergen is one of the most common clinical symptoms of food allergy in both adults and children. Especially often diarrhea is observed with food allergies to milk.

Allergic enterocolitis with food allergies it is characterized by sharp pains in the abdomen, the presence of flatulence, loose stools with discharge of vitreous mucus, which contains a large number of eosinophils. Patients with allergic enterocolitis complain of severe weakness, loss of appetite, headache, dizziness. Allergic enterocolitis, as a manifestation of food allergy, is more common than it is diagnosed.

Histological examination of patients with allergic enterocolitis reveals hemorrhagic changes, pronounced tissue eosinophilia, local edema and mucus hypersecretion.

Skin manifestations of food allergies are among the most common in both adults and children.

In children under one year of age, the first signs of a food allergy may be persistent diaper rash despite careful skin care, perianal dermatitis, and perianal itching that occurs after feeding. The localization of skin changes in food allergies is different, but more often they appear first in the face, periorally, and then acquire a tendency to spread the process throughout skin surface. At the onset of the disease with food allergies, a clear connection between skin exacerbations and the intake of a causal food allergen can be identified, but over time, allergic changes in the skin become persistent and constantly relapsing, which makes it difficult to determine the etiological factor.

For a true food allergy, the most characteristic skin manifestations are urticaria, angioedema angioedema and atopic dermatitis.

Pseudo-allergic reactions to food differ in the polymorphism of skin rashes: from urticarial (in 10-20% of cases), papular (20-30%), erythematous, macular (15-30%) to hemorrhagic and bullous rashes. Skin manifestations in any form of food allergy are usually accompanied by itching of varying intensity. Along with skin manifestations, patients with food allergies have a decrease in appetite, poor sleep, and asthenoneurotic reactions.

Respiratory manifestations of food allergies

allergic rhinitis with food allergies, it is characterized by the appearance of copious mucous-watery discharge from the nose, sometimes nasal congestion and difficulty in nasal breathing.

Rhinoscopy reveals swelling of the mucous membrane of the nasal concha, which has a pale cyanotic color.

Often, along with rhinorrhea or swelling of the mucous membranes, patients have sneezing, itching of the skin around the nose or in the nose. Most common causes development allergic rhinitis in patients with food allergies are fish and fish products, crabs, milk, eggs, honey, etc.

Food bronchial asthma. According to most researchers, the role of food allergens in the development of bronchial asthma is small. In our studies, clinical manifestations of food allergy in the form of asthma attacks were observed in approximately 3% of cases, and although the role of food allergens in the pathogenesis of bronchial asthma is disputed by a number of researchers, the significance of food allergens in the development of allergic reactions from the respiratory tract is undeniable and requires further study and clarification.

More rare clinical manifestations of food allergy

More rare clinical manifestations of food allergy include changes in the blood system, urinary, neuroendocrine and other body systems.

Allergic granulocytopenia. Symptoms of allergic granulocytopenia are more common in children and are clearly associated with intake of a causative food allergen.

The clinical picture of allergic granulocytopenia, caused by sensitization to food allergens, is characterized by a rapid onset associated with food intake, when chills, severe general weakness, and sore throat appear. Later, angina joins with necrotic and ulcerative lesions of the tonsils, palate, oral mucosa and lips. Patients have pallor of the skin, lymphadenopathy, enlarged spleen. These symptoms disappear with the elimination diet.

Allergic thrombocytopenia. The cause of allergic thrombocytopenia can be sensitization to milk, eggs, fish and fish products, sea shell animals, etc. We observed the development of allergic thrombocytopenia in children with sensitization to milk and carrots after eating carrot juice and cottage cheese (T.S. Sokolova, L.V. Luss, N.I. Roshal, 1974). In adults, the cause of the development of allergic thrombocytopenia can be sensitization to food cereals, milk, fish, etc.

The diagnosis of allergic thrombocytopenia is almost never immediately established due to the lack of specific symptoms. The disease begins with fever, hemorrhagic rashes on the skin, abdominal pain, arthralgia. In the analysis of urine, the presence of protein, leukocytes, single erythrocytes is noted. Changes in the composition of peripheral blood are ambiguous. In some cases, there is a sharp decrease in the platelet count, in others, the platelet count remains normal, but hemorrhagic rashes appear on the skin, and pathological changes (protein, leukocytes, erythrocytes) are noted in urine tests.

The diagnosis of food allergy in all the above cases is established not only on the basis of a positive allergological, food, pharmacological history, according to the results of a specific allergological examination with food allergens, but also on the basis of the complete disappearance of symptoms after the appointment of an elimination diet.

Clinical manifestations of food allergy are described in the form of migraine (Edda Haningten, 1986, etc.), fever, neuritis, Meniere's disease, cardiac arrhythmias, depression, etc. However, in many cases, the causal role of food allergens in the development of these symptoms is doubtful, since the diagnosis was based on the presence of a history of causation between the development of symptoms and food intake, but was not confirmed by the results of a specific allergological examination.

Food Allergy Diagnosis

Diagnosis of food allergy is very difficult due to the lack of unified methodological approaches, unified methods for diagnosing food intolerance, which allow to identify the whole variety of mechanisms of hypersensitivity reactions to food products. Food intolerance in true food allergy persists for many years, often throughout life, requires the development of individual elimination diets, affects the working capacity and quality of life of patients.

Pseudo-allergic reactions of food intolerance, as a rule, develop against the background of concomitant somatic pathology, often against the background of secondary immunodeficiency states, require a different algorithm for diagnosing and treating diseases.

The principles of diagnosing a true food allergy remain the same as for everyone. allergic diseases, and are aimed at identifying allergic antibodies or products of a specific interaction of antibodies with an antigen, as well as identifying reactions to foods that proceed according to a delayed type of hypersensitivity.

When diagnosing food allergies and food intolerances, special attention is paid to collecting an anamnesis of life and illness, analyzing data from an allergological, pharmacological, food anamnesis (Appendix 1) and a food diary (Fig. 3).

Rice. 3. Algorithm for the diagnosis of food allergy and food intolerance

To diagnose a true food allergy, methods of specific allergological examination and evaluation of clinical and laboratory data are used. TO specific methods Allergological examinations, the most commonly used in practical allergology, include: skin tests, provocative methods, methods for detecting allergen-specific IgE and IgG to food products.

Skin tests. Skin testing with food allergens is carried out by an allergist-immunologist in an allergological office and is necessarily included in the examination plan for patients with food allergies. Currently, domestic and foreign companies produce a wide range of food allergens of plant and animal origin, in particular: cereals ( Wheat flour, rye, oats, corn, etc.); rosaceous (apple, cherry, pear, plum, raspberry, blackberry, strawberry, apricot, peach, nectarine, etc.); buckwheat (buckwheat, rhubarb); nightshade (potatoes, eggplants, peppers, etc.); legumes (beans, soybeans, lentils, peas, peanuts, senna, etc.); walnut (walnut, gray, American, etc.); rue (orange, tangerine, lemon, etc.); mushrooms (yeast, champignons, etc.); heather (cranberries, lingonberries, blueberries, etc.); crustaceans (crabs, shrimps, lobsters, lobsters); mammals (beef, veal, pork, lamb, horse meat, rabbit meat, etc.), mammalian milk (cow, goat, mares, etc.); poultry (chicken, duck, geese, partridges, pigeons, etc.), bird eggs; fish (sea and river: cod, pollock, hake, sturgeon, herring, whitefish, eel, carp, etc. and their caviar); shellfish (mussels, oysters, scallops, squid, abalone, etc.); amphibians (frogs), etc. Positive skin tests with food allergens are detected in patients with true food allergy, proceeding by the IgE-mediated type. However, negative skin tests with food allergens make it possible to reject the diagnosis of food allergy with sufficient certainty, since the latter may develop through other allergy mechanisms.

Provocative methods are among the most reliable methods for diagnosing food allergies. Considering that provocative tests can lead to the development of a severe systemic reaction, they are recommended to be carried out only by a doctor, in a hospital or outpatient setting (in an allergology room located on the basis of a multidisciplinary hospital with an intensive care unit).

The diagnostic tests described in the literature, such as leukocytolysis reactions, leukocyte alteration, lymphocyte blast transformation, immune adherence, leukopenic and thrombocytopenic tests, are not used for the diagnosis of food allergies due to their low information content. The "hemocode" method for diagnosing food allergies cannot be used, since with its help it is impossible in principle to determine whether food intolerance belongs to true, regardless of whether or not allergic reactions are false.

To the most informative methods that allow to detect food allergies include the radioallergosorbent test (RAST), as well as tests using the CAP-system, MAST-CLA-system, etc. Opinions about the information content and reliability of agglutination, precipitation, passive hemagglutination tests for diagnosing food allergies are very controversial, and these methods are rarely used. Certain clinical significance is the detection of eosinophilia in the peripheral blood of patients suffering from food allergies. The presence of eosinophils in the coprogram is also characteristic.

Differential diagnosis of food allergy should be carried out with diseases of the gastrointestinal tract, mental, metabolic disorders, intoxications, infectious diseases, anomalies in the development of the gastrointestinal tract, insufficiency of the endocrine function of the pancreas, celiac disease, immunodeficiency states, overdose medicines, disaccharidase deficiency, endocrine pathology, irritable bowel syndrome, etc.

An example of malabsorption and carbohydrate metabolism is the deficiency of lactase, an enzyme that breaks down milk sugar- lactose.

In patients with lactase deficiency, after drinking milk, there is bloating, rumbling, diarrhea, loose stools.

Lactase deficiency can be complete or partial, congenital or acquired. It should be noted that lactose is fermented and partially destroyed in sour milk, so these patients tolerate sour-milk products better.

Deficiency of sucrose-isomaltose. With a deficiency of this enzyme, the breakdown of beet or cane sugar - sucrose is disturbed. Deficiency of this enzyme is rare.

Fructosemia is a disease associated with the absence of the enzyme aldolase, which is involved in the metabolism of fructose, as a result of which the metabolism of fructose stops at the formation of fructose-1-phosphate. The accumulation of this product causes hypoglycemia.

Clinical manifestations occur after ingestion of food containing fruit sugar (fruit, honey, cane sugar) and are characterized by the following symptoms: sweating, vomiting, nausea, there may be loss of consciousness and transient jaundice.

Fructosemia is a rare hereditary disease that occurs in an autosomal recessive manner. Interestingly, carriers of this disease avoid eating sweet food. Treatment consists of intravenous glucose.

Galactosemia - intolerance to galactose, refers to hereditary enzymes, is transmitted by a recessive type. The disease is based on a violation of the conversion of galactose to glucose due to the absence of the enzyme galactokinase, which leads to the accumulation of the enzyme galactose-1-phosphate, which damages the tissue of the kidneys, liver, and lens of the eye.

Clinical manifestations occur 2 weeks after birth. The newborn, who previously seemed healthy, loses his appetite, becomes lethargic, vomiting, jaundice appear, there is a rapid drop in body weight, hepatosplenomegaly, bleeding, cataracts. The treatment is to avoid milk.

There is a milder course of galactosemia, in which case the only symptom may be cataracts.

Violation of amino acid metabolism. Phenylketonuria (phenylpyruvic oligophrenia). The disease is characterized by the absence of the enzyme phenylalanine oxidase, which is necessary for the conversion of phenylalanine to tyrosine. Phenylalanine and its cleavage product, phenylpyruvic acid, accumulate in the blood, which cause brain damage.

Treatment is to avoid foods containing phenylalanine.

In recent years, cases of food intolerance due to mental disorders have become more frequent. Such patients develop abdominal pain, nausea, vomiting, dizziness, and other symptoms after ingestion of any food. Anorexia develops, leading to exhaustion. Such patients need to consult a psychiatrist and prescribe adequate therapy.

Food Allergy Treatment

The main principles of the treatment of food allergies are an integrated approach and stages in the conduct of therapy, aimed at both eliminating the symptoms of allergies and preventing exacerbations. Of paramount importance is the appointment of an adequate balanced diet, corresponding in volume and ratio of food ingredients to the age of the patient, his body weight, treatment concomitant pathology and correction of concomitant somatic diseases, primarily from the gastrointestinal tract (enzymes, probiotics, enterosorbents, etc.). Features of therapy and prevention of food allergies depend on the mechanisms of development of food intolerance, the stage and severity of clinical manifestations, the age of the patient, concomitant diseases and the living conditions of the patient.

Therapeutic and preventive measures for food allergies include the following basic techniques:

Elimination diet for true food allergies.

Rational nutrition with PAR.

Pharmacotherapy (symptomatic, basic preventive therapy, treatment of concomitant diseases).

Allergen-specific immunotherapy.

Immunomodulatory therapy (with a combination of food allergies with immune deficiency).

Educational programs (training medical workers, patients and their relatives in the allergy school).

Prevention:
- Primary;
- Secondary;
- Tertiary.

With true food allergy, as with any other allergic disease, specific and non-specific methods of treatment are used.

Nonspecific methods, or pharmacotherapy, are aimed at eliminating the symptoms of an advanced disease and at preventing exacerbations. Pharmacotherapy for food allergies is prescribed in acute period to eliminate the symptoms of a developed reaction, and basic therapy is used to prevent the occurrence of such reactions. Histamine is known to be one of the most important mediators responsible for the development of clinical symptoms of food intolerance. Therefore, a special role in the treatment of the disease is assigned to antihistamines.

There are three main groups antihistamines used for food allergies.
1. Drugs that block histamine receptors (H1 receptors), 1st generation, or classic antihistamines: chloropyramine (suprastin), clemastine (tavegil), hifenadine (fencarol), etc. and a new generation: cetirizine (zyrtec, cetrin , Parlazin), ebastine (Kestine), loratalin (Claritin, Erolin), fexofenadine (Telfast), desloratadine (Erius), levocetirizine (Xizal), etc.
2. Drugs that increase the ability of blood serum to bind histamine (histaglobin, histaglobulin, etc.), which are prescribed for prophylactic purposes. Currently, they are used less frequently, since for non-specific therapy there are medicines with a better safety profile that do not contain protein.
3. Drugs that inhibit the release of histamine from mast cells: ketotifen, drugs of cromoglycic acid (nalcrom), etc. This group of drugs is prescribed for prophylactic purposes for a long time, at least 2-4 months.

In the acute period, antihistamines are prescribed, the doses and method of administration of which (orally or parenterally) are determined by the severity of the reaction.

In acute systemic severe clinical manifestations of food allergy, glucocorticosteroids (in particular, dexazone, etc.), 1st generation antihistamines (suprastin, etc.) are administered parenterally.

1st generation antihistamines are competitive H1 receptor blockers and therefore their binding to the receptor is rapidly reversible. In this regard, to obtain a clinical effect, it is necessary to use these drugs in high doses and often (3-4 times a day), however, it is possible to use some drugs in combination with 2nd generation drugs when prescribed at night.

In the early 1980s, 2nd generation antihistamines were introduced into the practice of clinical allergology.

H1 antagonists of the new generation are distinguished by a high selective ability to block peripheral H1 receptors. They belong to different chemical groups. Most H1 antagonists of the 2nd generation bind to H1 receptors noncompetitively. Such compounds can hardly be displaced from the receptor, and the resulting ligand-receptor complex dissociates relatively slowly, which explains the longer action of such drugs. H1-antagonists of the 2nd generation are easily absorbed into the blood. Eating does not affect the absorption of these drugs. Most H1 antagonists are prodrugs and have an antihistamine effect due to the accumulation of pharmacologically active metabolites in the blood. Therefore, metabolized drugs show their antihistamine effect to the maximum after a sufficient concentration of active metabolites appears in the blood. Unlike metabolizable antihistamines, cetirizine is practically not metabolized and begins to act immediately. It is excreted mainly through the kidneys in unchanged form.

When prescribing antihistamines, one should take into account possible absorption disorders in the gastrointestinal tract and simultaneous intake of sorbents. Often, in acute systemic allergic reactions at the initial stage of therapy, preference should be given to parenteral forms. It is also necessary to take into account the bioavailability of the drug, for example, suprastin in injectable form has 100% instantaneous bioavailability. Lipophilicity also plays an important role - the higher the lipophilicity, the greater the bioavailability.

The effectiveness of antihistamines of both the 1st and the new generation is very high. To date, almost 60 years of experience in the use of 1st generation antihistamines has been accumulated, and over the past two decades, drugs of the 2nd, or new, generation have been widely used.

With the accumulation of clinical experience on the effectiveness of these drugs, data on unwanted effects drugs in this group. The main side pharmacological effects of H1-antagonists of the 1st generation: penetration through the blood-brain barrier; blockade of not only H1 receptors, but also M-cholinergic receptors; 5HT receptors; D-receptors; local irritating effect, analgesic effect, sedative effect. These drugs can cause dizziness, lethargy, gastrointestinal disorders (nausea, abdominal pain, loss of appetite), impaired urination, blurred vision. Side effects of 1st generation antihistamines are also manifested by dryness of the mucous membranes of the mouth, nose, and throat. The most characteristic and well-known side effect of 1st generation antihistamines is sedation associated with the penetration of these drugs through the blood-brain barrier and blockade of histamine receptors in the CNS. The sedative effect may vary from mild drowsiness to deep sleep. The most pronounced sedative properties were found in ethanolamines, phenothiazines, piperazines. Other manifestations of the action of H1 antagonists on the central nervous system may be coordination disorders, dizziness, a feeling of lethargy, and a decrease in the ability to coordinate attention. Rare side effects of 1st generation antihistamines include increased appetite (in piperidines). Tachyphylaxis (decrease in the therapeutic efficacy of the drug) is manifested to varying degrees in all 1st generation antihistamines.

The main advantages of the 2nd generation H1 antagonists are: high specificity and high affinity for H1 receptors; rapid onset of action; long-term action(up to 24 hours); lack of blockade of receptors of other mediators; obstruction through the blood-brain barrier; lack of connection of absorption with food intake; no tachyphylaxis.

The most widely used 1st generation antihistamines in practical allergology are: ethanolamines, ethylenediamines, piperidines, alkylamines, phenothiazines.

The ethanolamines are the following drugs: diphenhydroline, clemastine, etc. diphenhydramine (diphenhydramine) is one of the main representatives of 1st generation antihistamines. It penetrates the blood-brain barrier, has a pronounced sedative effect, moderate antiemetic properties. Clemastine (tavegil) in terms of pharmacological properties, it is close to diphenhydramine, but has a more pronounced antihistamine activity, a longer action (for 8-12 hours) and a moderate sedative effect.

The classical representatives of ethylenediamines include chloropyramine (suprastin), in the application of which vast experience has been accumulated. It has been shown that in allergic diseases accompanied by intense itching, the combined use of suprastin with a new generation antihistamine is possible (I.S. Gushchin, N.I. Ilyina, 2002). The parenteral form of the drug is often used for the initial treatment of allergic dermatosis, as it allows you to get 100% bioavailability of the drug and overcome the problem of absorption disorders in patients with food allergies.

Among the derivatives of piperidine, the most widely used cyproheptadine (peritol), which refers to antihistamines with pronounced antiserotonin activity. In addition, peritol has the ability to stimulate appetite, as well as block growth hormone hypersecretion in acromegaly and ACTH secretion in Itsenko-Cushing's syndrome.

A representative of alkylamines used for the treatment of allergic diseases is dimethindene (fenistil). The drug acts during the day, has a pronounced sedative effect, like other drugs of the 1st generation, the development of tachyphylaxis is noted. Side effects are also manifested by dryness of the mucous membranes of the mouth, nose, throat. In particularly sensitive individuals, urination disorders and blurred vision may occur. Other manifestations of the action on the central nervous system may be coordination disorders, dizziness, a feeling of lethargy, a decrease in the ability to coordinate attention.

Hifenadine (Phencarol) has a low lipophilicity, poorly penetrates the blood-brain barrier, there are indications that it has antiarrhythmic activity, activates diamine oxidase (histaminase), which destroys histamine. Due to the fact that the drug does not penetrate the blood-brain barrier well, after taking it, either a weak or no sedative effect is noted. Approved for use in young children.

Ketotifen (Zaditen) It is believed that it has an antiallergic effect due to inhibition of the secretion of allergy mediators from mast cells and blockade of histamine H1 receptors.

Among modern new generation antihistamines, the following groups are currently used in clinical practice: piperazine derivatives (cetirizine, levocetirizine), azatidine derivatives (loratadine, desloratadine), triprolidine derivatives (acrivastine), oxypiperidines (ebastine), piperidine derivatives (fexofenadine).

piperazine derivatives. cetirizine(cetrin, parlazin, zyrtec, etc.) is a selective blocker of H1 receptors, does not have a significant sedative effect, and, like other representatives of the 2nd generation, does not have antiserotonin, anticholinergic effects, does not enhance the effect of alcohol. Comparative studies have shown that cetirizine is more effective in suppressing the action of histamine than loratadine and fexofenadine. Only cetirizine has been shown to have true anti-inflammatory activity when taken in therapeutic doses in people. Cetirizine reduces the migration of eosinophils and neutrophils (by 75%), basophils (by 64%) and reduces the concentration of prostaglandin D2 (by 2 times) in the focus of allergic inflammation (E. Chalesworth et al.). Studies of other antihistamines have not shown this effect. In addition, the published results of the ETAC program (Early Treatment of the Atopic Child) testified to the preventive effect of cetirizine on the development of bronchial asthma in children. In a prospective study of 817 children with AD from families with hereditary burden of atopic diseases, it was shown that long-term use of this drug in the complex therapy of AD in a subgroup of 200 children halved the likelihood of developing bronchial asthma in case of sensitization to house dust (28.6 % among those receiving cetirizine compared to 51.5% among those receiving placebo) and to pollen (27.8% and 58.8%, respectively).

azatidine derivatives. Loratadine(claritin, erolin, etc.) - refers to metabolized H1 antagonists, is a selective blocker of H1 receptors, has no antiserotonin, anticholinergic action, does not enhance the effect of alcohol. Desloratadine (erius) is a pharmacologically active metabolite of loratadine, has a high affinity for H1 receptors and can be used at a lower therapeutic dose than loratadine (5 mg per day).

Oxypiperidines. Ebastin (Kestin)- a modern, highly selective non-sedating H1 antagonist of the 2nd generation. Refers to metabolizable drugs. The pharmacologically active metabolite is karebastin. Ebastine has a pronounced clinical effect in both seasonal and year-round allergic rhinitis caused by sensitization to pollen, household and food allergens. The anti-allergic effect of kestin begins within an hour after oral administration and lasts up to 48 hours. In pediatric practice, ebastine is used in children from 6 years of age. Kestin, unlike loratadine, can be prescribed in a double dose, which significantly increases its effectiveness, but at the same time, kestin does not cause side effects from the central nervous system and the cardiovascular system.

Piperidines. Fexofenadine (Telfast) is the final pharmacologically active metabolite of terfenadine and has all the advantages of H1-antagonists of the 2nd generation.

Drugs that increase the ability of blood serum to bind histamine. Histaglobulin (Histaglobin) represents combination drug, consisting of normal human immunoglobulin and histamine hydrochloride.

Drugs that inhibit the release of mediators from mast cells and other target cells of allergy. The antiallergic effect of this group of drugs is associated with their ability to inhibit the release of mediators from allergy target cells.

Preparations of cromoglycic acid (sodium cromoglycate). The theory of non-cytotoxic involvement of allergy target cells in the allergic response was finally formed in the 70s and served as a reason for the creation of drugs whose action is aimed at inhibiting the function of allergy target cells (I.S. Gushchin). Sodium cromoglycate, discovered in 1965 by Altounyan, met these requirements and found clinical use within 3 years. Sodium cromoglycate acts by a receptor mechanism, does not penetrate into cells, is not metabolized and is excreted unchanged in the urine and bile. These properties of sodium cromoglycate may explain the extremely low incidence of unwanted side effects. In food allergies, the oral dosage form of cromoglycic acid, nalcrom, is of particular importance.

Thus, the choice of antihistamines in the treatment of allergic diseases requires the doctor to take into account the individual characteristics of the patient, the characteristics of the clinical course of the allergic disease, the presence of concomitant diseases, the safety profile of the recommended medication. Of no small importance is the availability (in particular, the cost of the drug) for the patient.

Among modern antihistamines, there are medicines that have a high degree safety, which allows pharmacies to dispense them without a doctor's prescription. In particular, these drugs include Kestin, Zyrtec, Cetrin, Parlazin, Claritin, Telfast, Erius, etc. However, patients should be advised to consult with their doctor which of the drugs is most indicated for a particular patient with food allergies.

With clinical mild symptoms and moderate severity, it is recommended to prescribe new generation antihistamines and their generics: ebastine (Kestin), cetirizine (Zyrtec, Parlazin, Cetrin, Letizen, etc.), fexofenadine (Telfast), loratadine (Claritin, Erolin, Clarisens, etc.), desloratadine (erius). The principles of prescribing, schemes and methods of administering antihistamines for food allergies are the same as for other forms of allergic pathology.

When prescribing antihistamines, one should strictly adhere to the recommendations set out in the instructions for use, especially in children and the elderly and senile.

Antihistamines are prescribed in combination with complex therapy aimed at correcting concomitant somatic diseases.

There is evidence of high clinical efficacy of combined regimens for the use of antihistamines, which allow determining the individual sensitivity of the patient and choosing the most effective scheme treatment.

Combination therapy regimens

1. In allergic diseases with intense itching, the combined use of antihistamines of the 2nd and 1st generations is recommended (I.S. Gushchin, N.I. Ilyina, 2002) in the morning + in the evening 1 tab. erolin 1 tab. suprastin
2. Selection different drugs to the individual sensitivity of the patient 5-7 days suprastin -> 5-7 days parlazin -> 5-7 days erolin
Taking the drug for 5-7 days, in the absence of positive dynamics - changing the drug (based on the recommendations of the chief pediatric allergist of the Ministry of Health of the Russian Federation, Professor, Doctor of Medical Sciences V.A. Revyakina, State Research Center for Children's Health of the Russian Academy of Medical Sciences).

The combination of kestin with fencarol is also effective, both in adults and in children.

To specific treatments for food allergies include food allergen elimination and allergen-specific immunotherapy (ASIT).

Elimination of food allergen

Elimination, or exclusion from the diet of a causally significant food allergen, is one of the main methods of treating food allergies, and in cases where a food allergy develops to rarely consumed foods (for example, strawberries, chocolate, crabs, etc.), the only effective method treatment.

Elimination requires not only the exclusion of a specific food product responsible for the development of sensitization, but also any others in which it is included even in trace amounts.

When prescribing an elimination diet, it is necessary to strictly ensure that the patient receives nutrition corresponding in volume and ratio of food ingredients to body weight and age.

A major contribution to the development of elimination diets was made by Rowe, who developed elimination diets for patients with food allergies to milk, eggs, food cereals, and also to combined forms of food allergies.

With food intolerance, patients do not need elimination diets, but only adequate therapy and nutrition correction, corresponding to concomitant somatic diseases.

With a true food allergy, patients should be prescribed elimination diets with the complete exclusion of causally significant food allergens and other products in which they may be included. When prescribing elimination diets, it is important not only to indicate which foods are excluded from the diet, but also to offer the patient a list of foods that can be included in the diet. The elimination diet in terms of volume and ratio of food ingredients should fully correspond to the age of the patient, comorbidities and energy costs. Elimination of a food product is prescribed only with a proven allergy to it.

When prescribing an elimination diet, it is also necessary to exclude products that have cross-reactions with a food allergen (milk - beef, digestive enzymes; mold fungi - kefir, cheese, yeast baked goods, kvass, beer, etc.; plant pollen - fruits, vegetables, berries, etc. .).

In the absence of positive dynamics of food allergy symptoms within 10 days after the appointment of an elimination diet, the list of products recommended to the patient should be reviewed and the reason for the ineffectiveness of the prescribed diet should be identified.

Diet options for food allergies
1. Grain Free Diet: exclude cereals, flour and flour products, seasonings, sauces, etc.). Can: meat, fish, vegetables, fruits, eggs, dairy products, etc. (in the absence of allergies to them).
2. Diet with no eggs: exclude eggs and seasonings, mayonnaise, creams, sauces, confectionery, pasta and bakery products containing eggs). Can: meat, dairy products, cereals, flour and flour products without eggs, vegetables, fruits (in the absence of allergies to them).
3. Diet with the exclusion of milk: exclude milk and dairy products, cereals with milk, condensed milk, cottage cheese, sour cream, confectionery, pasta and bakery products containing milk), butter, cheeses, sweets containing milk. Can: meat, fish, eggs, cereals, vegetables and fruits, flour products without milk, etc. (in the absence of allergies to them).
4. Diet with the exclusion of milk, eggs and cereals: exclude products containing milk, eggs, food grains.

Currently, there is a large selection of industrial food products recommended for patients with true and false allergic reactions, both for children and adults, which include various mixtures based on milk protein hydrolysates, soy protein isolate, hypoallergenic monocomponent canned meats and purees, hypoallergenic dairy-free cereals, etc. In particular, for more than half a century, the West German company HUMANA has been offering a program of baby food, including therapeutic and preventive products and complementary foods. Most of the products included in it can be used by children of different ages and adults. In the development of the composition of the mixtures, all the latest achievements and requirements of the WHO and the European Society of Pediatricians, Gastroenterologists and Nutritionists are taken into account. For children with increased risk allergies, as well as for children with food allergies, intolerance to soy proteins, it is possible, starting from the first days of life, to recommend the "Humana HA1" mixture, which can be used both as the only food, in artificially fed children, and as an addition to breastfeeding immediately after breastfeeding or any other hypoallergenic milk formula for infants.

"Humana HA Porridge" is a special hypoallergenic porridge for children after 4 months of age and for adults. "Humana HA Porridge" is prescribed as an addition to breastfeeding, "Humana HA1", "Humana HA2" or any other food for children.

For example, "Humana SL" is made on the basis of vegetable protein. This product can be given from the first month up to school age. "Humana SL" does not contain cow's milk, milk protein, galactose, white sugar, gluten.

The calculation of the portion size of "Humana HN therapeutic nutrition" for one feeding depends on the individual characteristics of the child and adults (Table 3).

Table 3. Calculation of the serving size of "Humana HN Therapeutic Nutrition" per feeding

There are other nutrition programs for children and adults produced by domestic and foreign companies, which are prescribed taking into account indications and contraindications for their use.

In particular, the company "Heinz" produces porridge in the city of Georgievsk, Stavropol Territory, imports mashed potatoes, juices and biscuits from Italy, mashed potatoes and porridges from England.

The company "Heinz" categorically does not use genetically modified products (GMF) in food production and voluntarily analyzes raw materials (flour) and the finished product for the presence of GMF. All Italian food is produced under the Heinz-Oasis program, which means state certification of the entire production chain - from growing raw materials (vegetables and fruits) and animal fattening (meat) to 24-hour monitoring of the quality and safety of the finished product. The company guarantees food production from vegetable raw materials grown in the fields without pesticide and herbicide fertilizers, and the use of meat of animals fed exclusively with vegetable raw materials from certified sources, without the use of various food additives, raw materials that have not been exposed to antibiotics, etc. The plant has a list of herds by name, these the herds are periodically monitored by the veterinary services of Italy and the company, as is the case at the plants in England.

The Heinz company produces a wide range of nutrition, from which you can make a gluten-free diet, and a diet for children with lactase intolerance, and with food intolerance due to gastrointestinal pathology.

The greatest problems in compiling a diet arise for a doctor when prescribing nutrition for children in the first months of life who are bottle-fed. In these cases, children usually receive formula based on cow's milk. As clinical experience shows, it is at this age that symptoms of intolerance to milk mixtures and the need to include breast milk substitutes in the diet are noted.

In such situations, the doctor has to take into account a number of problems that arise when prescribing breast milk substitutes, namely: does the child have a true food allergy to cow's milk or only intolerance associated with disorders of the gastrointestinal tract or other reasons indicated above; the need for temporary prescription of breast milk substitutes in order to prevent subsequent sensitization to food in children with aggravated allergic heredity, especially for food allergies.

Depending on the characteristics of the clinical course of true and false food allergy to cow's milk, various mixtures are recommended for children. As mentioned above, there are mixtures based on soy, protein hydrolysates, amino acids, milk of other animals, fermented milk mixtures. With a true food allergy to cow's milk in children of the first year of life, formulas based on protein hydrolyzate can be recommended for nutrition (Table 4).

Table 4. Peptides with different molecular weights in hydrolyzed mixtures

The main disadvantages of hydrolyzed mixtures are high price product, low taste, insufficient accessibility for the population.

Scientific studies conducted in recent years by Russian and Western scientists have shown the effectiveness of replacing cow's milk with goat's in patients with food allergies, which is associated with the peculiarities of the physicochemical structure of goat's milk. In particular, in goat milk, the main casein fraction is beta-casein and lacks alpha S-1-casein and gamma-casein. In addition, the main whey protein in cow's milk is beta-lactoglobulin, which has a pronounced sensitizing activity, and in goat's milk, the main whey protein is alpha-lactalbumin (Table 5).

Table 5. Comparison of cow and goat milk proteins (g/l)

Moreover, goat's milk proteins differ from cow's milk in structural properties. Table 6 shows the content of the main nutrients in human, cow and goat milk.

Table 6. The content of the main nutrients in women's, cow's and goat's milk (per 100 ml) [according to I.I. Balabolkin et al., 2004]

Data on quantitative and structural differences in the content of food ingredients in women's, cow's and goat's milk served as the basis for the search and development of products based on goat's milk for use not only as a substitute for women's milk, but also in cases of intolerance to cow's milk, and food intolerance, caused by diseases of the gastrointestinal tract in adults.

BIBIKOL produces a line of powdered milk formulas based on goat's milk for children and adults. The adapted milk formula "NANNIE" is recommended for children from the moment of birth with the impossibility of breastfeeding and with intolerance to cow's milk and soy.

Vitaminized milk formula "NANNIE Golden Goat" is recommended for children over the age of one year, produced in New Zealand from organic goat's milk. It differs from the dry mixture "NANNIE for children from birth" in a higher content of protein, minerals and vitamins that meet the needs of a growing organism.

AMALTHEA - instant goat's milk for adults, is produced in Holland from fresh goat's milk using technology that preserves its biological value. It is recommended for patients with intolerance to cow's milk, pregnant and lactating women to meet the increased need for calcium, folic acid, vitamins, minerals and for the prevention of food allergies, as well as for elderly and senile people, athletes during intense training and stress.

There are other food products intended for patients with food allergies and food intolerances, information about which is available in the periodical press. In addition to the above food products, there are other offers from various domestic and foreign companies, acquaintance with which allows you to choose the most optimal individual diet.

hypoallergenic diet characterized by the exclusion from the diet of foods that have a pronounced sensitizing activity and contain foods rich in histamine, tyramine, histamine liberators.

For children aged 0 to 1.5 years, chicken eggs, fish, seafood, legumes, millet, nuts, peanuts, whole or diluted cow's milk and its dilutions are excluded from the diet.

In adults, alcoholic drinks (any), spices, smoked meats and other foods containing an excess of histamine, tyramine, nutritional supplements, biologically active additives(Appendix 2).

When prescribing a hypoallergenic diet to patients with PAR, the duration of its use and the order in which the diet should be expanded after the symptoms of food intolerance have been eliminated should be precisely indicated. Basically, a hypoallergenic diet is prescribed for a period of 3 weeks to 2 months. Patients receiving a hypoallergenic diet should keep a food diary, the analysis of which allows with sufficient probability to identify the main causes of food intolerance. A hypoallergenic diet is also prescribed as one of the stages of preparing the patient for provocative oral tests and conducting a double-blind placebo-controlled study with food.

Allergen-Specific Immunotherapy in case of food allergy, it is carried out only when the disease is based on a reaginic mechanism, and the food product is vital (for example, milk allergy in children). The first attempts to conduct ASIT for food allergies were carried out in the early 20s of the XX century. Various methods of its implementation have been proposed: pill, oral, subcutaneous. However, many researchers have concluded that ASIT with food allergens is ineffective in treating food allergies. However, we believe that the question of the advisability of holding specific immunotherapy in food allergy is not yet definitively resolved and requires further study.

Prevention food allergy is aimed at eliminating (preferably the most complete) causal food allergens, risk factors and provoking factors for the development of food allergies, taking into account age, the presence of a genetically determined predisposition to the development of allergies, and when adequately correcting concomitant somatic diseases.

Annex 1.

Nutritional history
(indicate the time of the last intake of the food product, the time of occurrence, the duration and characteristics of the clinical manifestations of the reaction, which stopped the reaction)

Products
Meat: beef, pork, lamb, other varieties
Fish and fish products
Bird
Butter: Butter, Sunflower, Olive, other varieties
Milk and dairy products
Eggs
Vegetables
Fruits
Berries
flour products
cereals
nuts
Coffee
Honey
Mushrooms
Chocolate
Spicy and smoked products

Appendix 2

General non-specific hypoallergenic diet

IT IS RECOMMENDED TO EXCLUDED FROM THE DIET:
1. Citrus fruits - oranges, tangerines, lemons, grapefruits, etc.
2. Nuts - hazelnuts, almonds, peanuts, etc.
3. Fish and fish products - fresh and salted fish, fish broths, canned fish, caviar, etc.
4. Bird - goose, duck, turkey, chicken, etc. - and products from it.
5. Chocolate and chocolate products.
6. Coffee.
7. Smoked products.
8. Vinegar, mustard, mayonnaise and other spices.
9. Horseradish, radish, radish.
10. Tomatoes, eggplants.
11. Mushrooms.
12. Eggs.
13. Fresh milk.
14. Strawberries, strawberries, melons, pineapples.
15. Butter dough.
16. Honey.
17. It is strictly forbidden to consume all alcoholic beverages.

FOR FOOD YOU CAN USE:
1. Lean boiled beef meat.
2. Cereal and vegetable soups:
a) on secondary beef broth,
b) vegetarian.
3. Butter, olive.
4. Boiled potatoes.
5. Kashi - buckwheat, oatmeal, rice.
6. One-day lactic acid products - cottage cheese, kefir, yogurt.
7. Fresh cucumbers, parsley, dill.
8. Baked apples.
9. Tea.
10. Sugar.
11. Compotes from apples, plums, currants, cherries, dried fruits.
12. White is not rich bread.

The diet includes approximately 150 g of proteins, 250 g of carbohydrates, 150 g of fats, which corresponds to an energy value of about 2800 kcal.

RECOMMENDED READING
1. Clinical reactions to food. Ed. M.Kh. Lessof. M., Medicine, 1986, 254 p.
2. Clinical allergology. Under. ed. R.M. Khaitova. M., "MEDpress-inform", 2002, 623 p.
3. Borovik T.E., Revyakina V.A., Makarova S.M. Modern ideas about clinical nutrition with food allergies in young children. Doctor. Ru, 2004, No. 2, p. 2.
4. Luss L.V. food allergy. Allergy, asthma and wedge. immunol., 2002, vol. 6, no. 12, p. 3-14.

Description

Method of determination Chemiluminescent immunoassay.

Material under study Serum

Determination of immunoglobulins of the IgG class to one of the most powerful allergens in cow's milk - beta-lactoglobulin.

See also test No. 649 Beta-lactoglobin, IgE (Food - Beta-lactoglobulin, IgE, F77).

Beta-lactoglobulin is one of the proteins in cow's milk. Not present in breast milk. It is one of the strongest allergens among all cow's milk proteins. Destroyed at 20-minute boiling. Sensitization can occur even in the womb, with abuse during pregnancy or during lactation with dairy products.

The most common clinical manifestations of such an allergy can be skin manifestations (itchy rash, eczema, dermatitis), gastrointestinal symptoms (abdominal pain, vomiting, diarrhea, flatulence and constipation), and sometimes respiratory symptoms (cough, asthma attacks, rhinitis). Cow's milk allergy can sometimes cause a cross-reaction when eating beef.

The vast majority of food allergies are IgE-mediated allergic reactions. Basic laboratory diagnostic allergy tests are based on the presence of specific IgE antibodies in the blood (see definition of specific IgE).

IgG antibodies are often found in food allergies, detectable IgG are not necessarily reactive to the same proteins as IgE, their role is not completely clear. Potentially, they can participate in food hypersensitivity reactions: it has been shown that degranulation of mast cells and basophils can be induced not only by the complex of IgE and antigen, but also by other stimuli, for example, anaphylotoxins C3a and C5a, which are produced during the alternative (IgG4 is involved) or classical ( involved IgG1, IgG2, IgG3) complement activation pathways.

But it is also known that IgG antibodies to the allergen can also perform the function of blocking antibodies, which reduce the severity of allergic reactions that occur with the participation of specific IgE. IgG antibodies to food allergens can be found in healthy people as evidence of increased consumption of certain products without the presence of allergies to them.

Diagnostic value the fact of detecting an increased amount of IgG to food allergens in the patient's blood is debatable. The study of IgG to food allergens is usually carried out in addition to the study of IgE, in order to select the optimal change in diet with the exclusion or rotation of individual food components, which can significantly improve the patient's condition.

The appointment and interpretation of the test results should be done by a specialist representing the limitations this study and considering it in combination with clinical and anamnestic data and the results of other tests.

Preparation

It is preferable to withstand 4 hours after the last meal, there are no mandatory requirements. It is undesirable to conduct a study against the background of the use of glucocorticoid hormone preparations (you should consult with your allergist regarding the advisability of canceling). Antihistamines do not affect the result.

Indications for appointment

• In a complex of studies to identify the potential pathogenetic role of individual allergens (in addition to the study of IgE antibodies).
• In order to select a diet for patients with hypersensitivity to food ingredients.

Interpretation of results

The interpretation of test results contains information for the attending physician and is not a diagnosis. The information in this section should not be used for self-diagnosis or self-treatment. Accurate Diagnosis puts the doctor, using both the results of this examination¤, and necessary information from other sources: anamnesis, results of other examinations, etc.

Units of measurement in the INVITRO laboratory: mg/l. Interpretation of results: Reference values.

Allergy to cow's milk has been known to people since ancient times. Even before our era, the great ancient Greek physician Hippocrates described this condition. In our time, according to medical statistics, up to 5% of young children experience manifestations of this disease. In adults, a true allergy to cow's milk is rare, but many develop an intolerance to it, associated with a lack of enzymes necessary for its digestion.

Cow's milk allergens

Allergies are caused by proteins in milk. There are about 20 different types of proteins in milk, 4 of them are considered allergenic. These are casein, beta-lactoglobulin, alpha-lactalbumin and lipoproteins.

• Casein is the main protein of milk, in cow's milk it makes up more than 80% of all proteins contained in it. Casein is present in the milk of all mammals, so if you are allergic to it, a reaction will be observed on any milk: goat, mare, etc., as well as on fermented milk products and cheeses, since it is also present in them.
• Beta-lactoglobulins are also part of the milk of all animals, in the composition of cow's milk they account for about 10% of the total amount of proteins.
• Alpha-lactalbumin is a species-specific protein, so if the allergy is due to an increased sensitivity of the body to it, then most likely there will be no allergy to the milk of other animals. However, in the presence of a reaction to alpha-lactalbumin, an allergic reaction to meat - beef - is also very likely.
• Lipoproteins are considered the weakest of the "milk" allergens. However, they are part of not only milk and sour-milk products, but also butter, and are "responsible" for allergies to it.

Types of allergic reactions to milk

Approximately half of those who are allergic to cow's milk develop an immediate reaction, which occurs within a short period of time after ingestion of a product containing milk: from several minutes to several hours. Perhaps the appearance of skin reactions such as urticaria, allergic rhinitis, an attack of bronchial asthma. IN rare cases anaphylactic shock may also develop.

The other half of the patients have a delayed-type reaction. Allergic manifestations occur within a few hours to 2-3 days after consumption allergenic product and most often manifest as gastrointestinal symptoms (diarrhea, vomiting).

Prevention and treatment

The main thing in the prevention and treatment of cow's milk allergy, as in other types of allergies, is to exclude contact with the allergen, that is, do not consume milk and products containing it. This is where the main difficulty lies, since products containing milk or its derivatives (kefir, cottage cheese, cheeses, butter) are found literally at every step ... Butter dough and any pastries from it, ice cream and milk chocolate , not to mention all sorts of yoghurts and cottage cheese, milk porridge and soup with sour cream ... All this should be excluded from the diet.

Remember also that milk is often included in products where you don’t expect it at all. For example, powdered milk added to some sausages, and condensed milk - to many sweets. Yes, by the way, both powdered and condensed milk contain the same complete set of allergens as whole milk.

For infants, there are special hypoallergenic mixtures based on soy, goat's milk, fermented milk. In severe cases, mixtures based on deeply hydrolyzed milk proteins are used, which contain not proteins, but their hydrolysates, that is, substances resulting from their partial breakdown. Mixtures based on hydrolysates are very expensive and very tasteless, but sometimes only they become the only salvation.

Many children outgrow their milk allergy by the age of 2-3, due to the maturation of their gastrointestinal tract. But for some people, this allergy persists for life ...

Medical treatment of cow's milk allergy is based on the same principles as the treatment of other types of allergy. Antihistamines are prescribed, as well as drugs that relieve specific manifestations of allergies, for example, various ointments for skin reactions. Only a doctor can select specific drugs that will help in your case.

Quantitative determination in the blood of specific immunoglobulins of class E to

one of the main allergens in cow's milk - whey protein alpha-lactalbumin.

Russian synonyms
Class E specific immunoglobulins ?-lactalbumin cow's milk.

English synonyms
ImmunoCAPf76 (Cow'sMilk, Alfa-lactalbumin, nBosd 4), IgE; Cow'sMilkAlfa-lactalbumin (nBosd 4), IgEAbinSerum; ?-LactalbuminnBosd4, IgE.

Research method

Three-dimensional porous solid phase immunofluorescence reaction, IFL (ImmunoCAP).

Units

kU/l (kilo unit per litre).

What biomaterial can be used for research?

Venous or capillary blood.

General information about the study

An allergen is a substance that causes an allergic reaction. In atopic diseases, allergens stimulate the formation of IgE antibodies and are causal factors in the development of clinical symptoms of allergic diseases. The detection in the blood of specific immunoglobulins E to a certain allergen confirms its role in the development of an allergic type I reaction (reaginic), and therefore allows you to determine the possible "culprit" of the allergy and prescribe appropriate therapeutic and preventive measures.

However, the composition of the allergenic substance includes not one, but several protein structures that can act as allergens. Some are "major" - the main allergens, others are "minor" - secondary. This allows you to differentiate true and cross allergies.

A food allergy is a food-induced reaction that is based on immune mechanisms. It can often be confused with food intolerance associated with other causes (features of cooking, product composition, metabolic disorders, gastrointestinal diseases). The unreasonable exclusion of non-allergenic food products for humans or, conversely, their use in the presence of allergies can have a negative effect on the body.

Food allergy is more often observed in children of the first years of life, mainly up to 3 years of age. One of the most common food allergens is milk. In children sensitized to cow's milk, allergy can be manifested not only by skin symptoms, but also by damage to the digestive tract, rhinitis, exacerbation of asthma, and anaphylactic reactions. Hypersensitivity to cow's milk does not always disappear in childhood and may persist for many years into adulthood or for life.

Cow's milk contains about 40 proteins that can act as allergens. Taking into account physical and chemical properties they are divided into caseins (80% of milk proteins) and whey proteins (20%). Serum contains predominantly globular proteins, beta-lactoglobulin and alpha-lactalbumin, and to a lesser extent bovine whey protein, lactoferrin, immunoglobulins. Alpha-lactalbumins and beta-globulins are synthesized in the mammary glands, while bovine whey protein, lactoferrin and immunoglobulins are absorbed from the blood.

The antibody response to milk proteins varies greatly from person to person, so there is no specific allergen that could be considered a major factor in cow's milk allergenicity. In most cases, IgE antibodies are simultaneously detected to several milk proteins, among which casein (Bosd 8), beta-lactoglobulin (Bosd 5) and alpha-lactalbumin (Bosd 4) are considered major.

Alpha-lactalbumin is a 14.2 kDa monomeric globular calcium-binding protein that makes up 25% of whey proteins and about 5% of all milk proteins. In the secretory cells of the mammary gland, it acts as a regulator of lactose synthesis. The structure of bovine alpha-lactalbumin is 72% similar to human, has antibacterial and immunostimulating properties, which makes it a very important component of baby food. There are special formulas for baby food, in which the concentration of alpha-lactalbumin is increased, and beta-lactoglobulin is reduced.

The allergenicity of a protein depends on its conformational structure, and cross-reactivity with milk alpha-lactalbumins from other animal species is possible but not well understood. IgE antibodies to beta-lactoglobulins and alpha-lactalbumins in 10% of cases have cross-reactivity.

The purpose of this study is to determine specific IgE to the native (obtained from natural raw materials) allergen of cow's milk - alpha-lactalbumin (nBos d 4) by the ImmunoCAP method. Allergy diagnostics with ImmunoCAP technology is characterized by high accuracy and specificity, which is achieved by detecting low concentrations of IgE antibodies in a very small amount of the patient's blood. The study is based on the immunofluorescence method, which allows to increase the sensitivity by several times compared to other diagnostic methods. Worldwide, up to 80% of the determinations of specific IgE immunoglobulins are performed by this method. The World Health Organization and the World Allergy Organization recognize ImmunoCAP diagnostics as the "gold standard", as this technique has proven its accuracy and stability of results in independent studies.

What is research used for?

• Diagnosis of allergy to whey proteins of cow's milk;
• selection of hydrolyzed mixtures for nutrition of young children.

When is the study scheduled?

• With sensitization to cow's milk;
• when selecting hydrolyzed mixtures for young children;
• when examining children with atopic dermatitis, urticaria, angioedema, bronchial asthma, allergic rhinitis / conjunctivitis, gastrointestinal disorders, anaphylactic shock and other manifestations of allergic diseases.

What do the results mean?

Reference values: negative.

Reasons for a positive result:

• sensitization to one of the main ("major") cow's milk allergens - alpha-lactalbumin.

Reasons for a negative result:

• lack of sensitization to this allergen;
• prolonged restriction or exclusion of contact with the allergen.

Important Notes

The performance of this study is safe for the patient compared to skin tests (in vivo), as it excludes the patient's contact with the allergen. Taking antihistamines and age characteristics do not affect the quality and accuracy of the study.

Serum total immunoglobulins E (IgE)

Allergochip ImmunoCAP

Allergological examination for eczema

Allergy component f77 - Beta-lactoglobulin nBos d 5, IgE (ImmunoCAP)

Allergy component e204 - Bovine serum albumin nBos d6, IgE (ImmunoCAP)

determination of specific class E immunoglobulins to other allergens

Who orders the study?

Allergist, gastroenterologist, pediatrician, dermatologist, pulmonologist, otolaryngologist, therapist, general practitioner.

Literature

1. Monaci L, Tregoat V, van Hengel AJ, Elke Anklam. Milk allergens, their characteristics and their detection in food: A review. Eur Food Research Tech 2006;223(2):149-79
2. Wal JM. Bovine milk allergy. Ann Allergy Asthma Immunol 2004;93(5 Suppl 3):S2-11
3. Lien EL. Infant formulas with increased concentrations of alpha-lactalbumin. Am J Clin Nutr 2003;77(6):1555S-8S
4. Permyakov EA, Berliner LJ. Alpha-Lactalbumin: structure and function. FEBS Lett 2000;473(3):269-74
5. Baroglio C, Giuffrida MG, Cantisani A, Napolitano L, Bertino E, Fabris C, Conti A. Evidence for a common epitope between bovine alpha-lactalbumin and beta-lactoglobulin. Biol Chem 1998;379(12):1453-6

bovine serum).

When boiled, casein is not destroyed and retains its allergenic activity, beta-lactoglobulin loses allergenic properties when heated to 130 0 C, and alpha-lactalbumin is thermolabile and loses its sensitizing properties when heated to 56 0 C.

For people who are allergic to cow's milk, it is not always possible to replace it with goat's or other types of milk. In any case, if you are prone to food allergies to cow's milk proteins, then you need to pay close attention to the composition of foods.

It should also be noted that, in the process of rearing farm animals, foreign substances inevitably get into the milk. We are talking about antibiotics, pesticides, hormones and other substances used in animal husbandry. It is worth remembering that any of them, entering the body, can cause. In this case, the occurrence of a rash or dyspepsia will depend on the brand and batch of the dairy product.

Along with an allergy to milk, it is necessary to highlight adverse reactions associatedwith features of absorption and breakdown of carbohydrates contained in milk (lack or lack of lactase), which are related to.

Allergy to milk while breastfeeding.

It is mother's milk that optimally meets the nutritional needs of the newborn. In addition, mother's milk plays important role in full physical and mental development child, and also contains a set of factors .

Allergy to mother's milk is extremely rare. If, during breastfeeding, the child develops any allergic reactions (rash, eczema, dyspepsia), then, first of all, you should pay attention to the diet of the mother: breast milk the child is given substances that are actively involved in the process of an atopic reaction (,).

If at least one of the parents had allergic reactions or the expectant mother suffering from allergies used foods that cause atopic symptoms during pregnancy, then the allergy in the baby can be laid down in utero. Also, the child's allergic phenotype is programmed in chronic placental insufficiency, when the immune response system experiences significant antigenic aggression from the mother's body.

Thus, during pregnancy and breastfeeding, the expectant mother is prescribed a hypoallergenic diet, with the exception of products with a potentially high allergenic potential:

• whole cow's milk;
• fish, shellfish and crustaceans;

In addition to the diet, the expectant mother should be careful with products that have a long shelf life and contain many preservatives and, since the latter often are and provoke or enhance allergic reaction.

Mechanism of development of allergy to milk.

The most common reason for the development of milk allergy is the early introduction of dairy products into the diet of children, as well as the use of milk as the main food product in children of the first year of life. In infants, the gastrointestinal tract is just beginning to form, so cow's milk protein is perceived by the child's body as a foreign agent and an allergic reaction develops in response to its intake.

Only by six months does an already functional, but still immature immune system appear, capable of secreting immunoglobulin A. Until this time, immunoglobulin A is found only in mother's milk, and it also creates a protective layer that prevents the absorption of any allergens.

Children with a hereditary predisposition may produce completely different immune responses.

The place of milk and dairy products in the diet.

Milk- a valuable nutritious product consisting of, and.

Milk contains from 2.7% - 3.6% of proteins. The proteins of milk and dairy products are biologically valuable, that is, they contain essential amino acids that the human body is not able to synthesize itself. The biological value of whey proteins is higher than casein. In case of allergy to milk, it is necessary to choose an adequate and complete replacement for the protein component. This may be, in the absence of an allergic reaction to them.

Milk fats are highly valuable fats, as they are quite easily absorbed due to the fact that they are in an emulsion and easily melt (at a temperature of 28-36 0 C). There are about 20 fatty acids in milk fat, including polyunsaturated oleic and low molecular weight fatty acids - caproic and caprylic. Milk and dairy products have a good lipotropic effect, due to the high content of lecithin and methionine.

Milk carbohydrates are represented mainly by milk sugar -.

Clinical manifestations of allergy to milk.

All symptoms develop almost instantly after taking milk or dairy products.

1. Profuse regurgitation after feeding.
2. Nausea.
3. Diarrhea interspersed with blood, which is a reliable diagnostic sign of a severe allergy to milk.
4. Rash.
5. Frequent unreasonable crying.
6. Minor weight gain.
7. Increased gas formation.
8. Copious mucus in nose and throat.
9. Wheezing breath.
10. Loss of appetite.
11. Dehydration.

In the presence of other allergens in milk, as well as allergies of a different origin, an allergic reaction to milk can become more acute or even paradoxical.

Diagnosis of allergy to milk.

• Skin prick tests are the most effective in diagnosing cow's milk protein allergy.
• A blood test for total IgE is not informative: unfortunately, if a child suffers from any other type of allergy, then total immunoglobulin E will also be elevated, so it will not be possible to identify a specific allergy to milk. However, even at normal values total IgE there may be an allergy to cow's milk protein in the absence of an exacerbation or with a low severity of the disease. A blood test for specific IgE to milk allergens will help to reliably establish the allergic reaction mechanism to milk.
• Elimination diet - confirms the reaction to a specific food.
• Food provocation - is prescribed when the allergy symptoms have passed, but the doctor needs to determine whether this reaction was associated with milk allergens.

Treatment of allergy to milk.

At the first suspicion of allergy to cow's milk protein, it is necessary to exclude this product from the child’s diet, remove not only whole milk, but also carefully study the composition of the mixture; the child must be accustomed to fermented milk mixtures gradually, they should be introduced into complementary foods in minimal quantities. The presence of traces of milk allergens in all doubtful cases should be checked in an accredited laboratory.

Please note that cow's milk protein is present not only in milk mixtures, but also in cereals and baby purees. If a child has an allergic reaction to milk protein at an older age, it should be remembered that milk and its products are widely used in the food industry and can be found in bread, confectionery and pancakes, some soups, ham and sausages, sweets, and even in marshmallow (hydrolyzed milk proteins serve as a whipped base). In some cases, milk allergy may go away on its own after three years.

With the exclusion of milk and dairy products from the diet, the diet is built taking into account the adequate replacement of biologically valuable substances, primarily protein.

Milk alpha-lactalbumin cross-reacts with egg protein (ovalbumin) and bovine whey protein cross-reacts with beef and veal.

Alternative types of milk.

Only after the permission of the doctor, you can try to introduce into the child's diet not cow's milk, but its substitutes.

• Rice milk.
• Oat milk.
• Soy milk is vegetable milk, which contains up to 40% protein, as well as most of the minerals and amino acids necessary for the human body.

Thus, avoiding contact with milk allergens, especially when sensitized to thermostable allergens, is quite difficult. However, there are now specialty products that do not contain the milk food allergens described above. You can purchase these products at

Literature:

1. Kolkhir P.V. Evidence-based Allergology and Immunology Practical Medicine Moscow 2010.
2. Scott H Sicherer, MD; Chief Editor: Michael A Kaliner, MD Food Allergies May 2, 2014
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