FOOD ALLERGY

From Big Medical Encyclopedia

FOOD ALLERGY (grech, alios another + ergon action) — the allergic reactions arising on foodstuff in connection with reaction of food antigens with the corresponding antibodies or sensibilized lymphocytes.

A number of researchers distinguishes, except food, alimentary and digestive (digestivny, or gastrointestinal) an allergy. At food allergy allergen is the foodstuff or substances which are formed at its long-term storage, culinary processing. At an alimentary allergy the sensitization of an organism occurs the nonfood allergens getting into an organism with food or per os (the preservatives, dyes, chemical impurity and other substances applied in the food industry and also house and production dust, vegetable, medicinal, epidermal and other allergens). Any foodstuff can include the whole complex of the sensibilizing substances. At a digestive allergy receipt of the allowing dose of allergen is carried out in any way, except peroral — at inhalation, contact with skin and mucous covers, hypodermic or intravenous administration of antigens. In these cases the digestive tract acts as «shock» body, allergic reaction develops in Krom (see. Antigen — an antibody reaction ).

Still the painful states connected with consumption of these or those products were known to doctors of antiquity. Hippocrates specified that milk can cause a gastric disturbance and a skin itch. Descriptions a wedge, manifestations of hypersensitivity to foodstuff meet in medical literature of the Middle Ages, in a wedge, the managements of 19 century. Scientific development of questions of an etiology and P.'s pathogeny and. began in 20 — the 30th there are 20 century when the role of a hyperpermeability of an enterohepatic barrier and absorption of not completely split protein of food was shown. Immunol, mechanisms of an allergy to foodstuff began to be studied in the 70th years 20 century.

The intolerance of foodstuff not always has allergic character, i.e. is not always connected with immune mechanisms; it can develop from a set of the reasons: functional and organic diseases of the digestive system, enzymatic insufficiency, intestinal dysbacteriosis, psychogenic factors, etc. So, the reactions of not immunological genesis immunological more often externally similar to allergic can cause nutritional supplements (dyes, preservatives). Not all patients with complaints to intolerance of foodstuff have an allergy, and for its proof special researches are necessary. P.'s frequency and. among all allergic diseases from 5 to 50% hesitate. In the USA P. and. suffers apprx. 10% of the population, and one third falls on children's age since allergization of children is promoted by artificial feeding, at Krom through unripe went. - kish. a path foreign, antigennootlichny proteins are entered into an organism. Item and. occurs among patients with diseases of the digestive system in 10 — 20% of cases, with bronchial asthma — in 5 — 26%. P.'s combination of ampere-second an allergy medicinal, pollen, household or bacterial meets more often.

The etiology and a pathogeny

Any food stuff can become food allergen (see) and under the corresponding conditions to cause sensitization (see). Frequency of an allergy to these or those products changes depending on a geographical zone and character of food of the population. The most widespread food stuffs in this region, as a rule, are also allergens. The most frequent food-borne allergen both at early children's age, and at adults is the cow's milk containing a set of antigenic components from which are most studied lactalbumin, a r-laktoglobu-lean, casein, lipoproteids, proteoses and peptones. Lactoglobulin is the most antigenically active. Women's milk does not contain r-lactoglobulin and is deprived of allergenic properties. Existence even in small amounts of proteinaceous components of cow's milk in various foodstuff (cottage cheese, oil, cakes, etc.) can cause allergic reactions in sensibilized persons at their use. Whole milk causes an allergy more often, than acid or undergone other processing. Eggs also contain a number of antigenic substances, napr, ovalbumin, kanalbumin, ovomucoid, vitellin. During the cooking activity of ovalbumin decreases owing to what abrupt ovalbumin has allergenic property to a lesser extent, than crude.

Fish often causes allergic reactions; during the cooking it in insignificant degree loses the allergenic properties. Item and. it is noted to crabs, crayfish, oysters. Meat less than fish, causes P. a.g at the same time can be observed by P. and. to meat of only one or several animal species.

From cereals the most widespread allergen is wheat. Vegetables, fruit and berries quite often are food-borne allergens. The sensitization, especially at children's age, arises more often not to one any product, and to group of related fruits and fruit, napr, to a citrus (lemons, oranges, tangerines, grapefruits), berries (a wild strawberry, strawberry, currant), etc. It depends on a community of antigens in related plants. At the same time specific specificity of antigens can remain owing to what at many patients P. is observed and. only * to oranges, either plums, or a wild strawberry. To number of the products causing P. and., it is necessary to carry also honey, chocolate, nuts. To P.'s development and. genetic predisposition, climatic and seasonal factors, acute and hron, diseases of a digestive tract promote.

Leading role in origins of P. and. belongs to disturbance of processes of digestion and absorption of components of food, receipt in blood of the not completely split proteinaceous products which kept the antigenic properties. It is promoted by enzymatic insufficiency, pathology of pristenochny digestion, and also inflammatory and dystrophic changes of a mucous membrane of a small bowel. The large role is played also by a genetic factor, in particular decline in the ability of a mucous membrane of a gut to cosecrete immunoglobulin A which deficit leads to the accelerated absorption of feedstuffs. At repeated contact of antigens (see) with a mucous membrane of intestines the local sensitization of fabrics matters that stimulates synthesis antibodies (see) in lymphoid elements of an intestinal wall.

In P.'s development and. play a role of an antibody of reaginic type, (IgE), not - reaginic (IgG) and other immunoglobulins.

Emergence of a sensitization in the embryonal period can be promoted by passing through a placenta of IgG and its fragments, at early children's age — existence in composition of women's milk of all classes of immunoglobulins, including IgE.

Clinical manifestations

P. and. it is diverse and depends on reactivity of an organism, forms of a sensitization, properties of allergen, funkts, conditions of bodies in which there is an allergic reaction. Reception of the same product can cause rough displays of a disease or the wedge, symptoms is not followed any. Item and. treats preferential allergic reactions of immediate type (see. Allergy ), therefore the wedge, symptoms in typical cases come in a short space of time after meal (of 5 — 10 min. till 3 — 4 o'clock). For acute P. and. the sudden onset of the illness (soon after reception of a food-borne allergen), emergence of the general allergic reactions — a skin itch is characteristic, small tortoiseshells (see), a Quincke's edema (see. Quincke hypostasis ), bronchospasms (see), migraines (see), polyarthralgias decrease in the ABP.

When allergen is in daily eaten food, allergic reactions are played repeatedly, but in the erased form — hron, food allergy. At the same time hardly happens to establish the nature of allergen especially as repeated allergic reactions in itself lead to functional, and then and organic lesions of various bodies, first of all a digestive tract. Symptoms of allergic and not allergic defeat of bodies of the alimentary system quite often closely intertwine among themselves that creates very difficult a wedge, a picture.

At meal, containing food-borne allergens, can appear catarral, aphthous or a canker of an oral cavity — ulitis (see), glossitis (see), stomatitis (see), and also esophagitis (see) and cardiospasm (see). Most often at P. and. the stomach is surprised. There are typical symptoms gastritis (see), similar to a syndrome of «the angry stomach» — pain or weight in epigastric area, bitterness in a mouth, an eructation, heartburn, nausea, vomiting (emetic masses quite often contains a large number of a gastric juice at the expense of hypersecretion), tension of an abdominal wall. Abdominal pains happen so intensive that they are called even «belly migraine», and the general phenomena (tachycardia, decrease in the ABP, dizziness, a headache) accompanying a painful symptom — «a vegetative storm». At the same time there can be a skin itch, a small tortoiseshell, a Quincke's edema, etc. At P. and. defeat of thin and thick guts is most often noted. There are acute skhvatkoobrazny, the aching dull aches on all stomach which are followed by rumbling, swelling and transfusion, and also imperative desires on bowel emptying are more rare. There is a frequent liquid chair, is frequent with impurity of undigested food, slime, sometimes in the form of films, is more rare — blood.

At P. and. quite often there are attacks of bilious colic as a result of diskineziya of a gall bladder, bilious ways and Oddi's sphincter that the hypochondrium leads to kolikoobrazny pains in right, to-rye quite often are followed by head and cardiac pains, a bronchospasm, a small tortoiseshell and other general allergic reactions. Item and. can be the cornerstone so-called. postcholecystectomy syndrome (see); e.g., patients with an allergy to milk can have a jaundice, a hepatomegalia, a polyarthralgia, urticaria, dermatitis; there can be symptoms of pancreatitis and enzymatic dysfunction of a pancreas less often.

At heavy the wedge, a picture can appear the hypostasis of a throat and bronchial tubes complicating breath; sharp falling of the ABP and acute cardiovascular insufficiency owing to anaphylaxis (see); hematencephalons, in an abdominal cavity or other bodies. Sometimes after P. and. the polyvalent allergy develops, it is especially frequent to pharmaceuticals. Nek-ry researchers point to an agranulocytosis, a hemorrhagic vasculitis, collagenoses as P.'s complication and.

The diagnosis

the Diagnosis is complicated and the wedge, observations, laboratory and other diagnostic methods is established on the basis of data of the allergological anamnesis. The allergological anamnesis allows to find out genetic predisposition of the patient and his immediate family to these or those allergic diseases. At erased a wedge, a picture of a disease only after 2 — 4 weeks maintaining the food diary, in Krom celebrate date and time of meal, structure and amount of foodstuff, a way of culinary processing, observed painful symptoms, it is possible to establish a source of allergization.

An eliminative diet (see. Eliminative tests ) and provocative tests (see), napr, leykotsitopenichesky test (see) and thrombocytopenic test (see), a wedge, P.'s diagnoses are by the main methods and.

To laboratory diagnostic methods refer definition of humoral antibodys and a cellular sensitization to foodstuff by means of various techniques. Direct proof of P. and. detection in blood serum of the sick freely circulating antibodies to foodstuff by means of allergy diagnostic tests, napr is, basphilic test (see). The greatest significance is attached to definition in blood serum of total quantity of IgE and allergic antibodies by means of the radioallergosorbent test (see. Radioallergosorbent method ), which is considered the best for identification of reagins at an atopic allergy, including food. Increase in the general IgE level and specific antibodies to this or that food-borne allergen usually confirms P.'s diagnosis and.

Additional value in P.'s diagnosis and. have skin tests (see) with food-borne allergens. Radiological and electrographic researches of motility went. - kish. a path at introduction of a food-borne allergen also help with P.'s identification and.

Differential diagnosis Item and. it is carried out with an alimentary allergy, with medicinal allergy (see) and other general allergic diseases (see. Allergic diseases ), to-rye are caused by nonfood allergens, with food toxicoinfections (see. Toxicoinfections food ), with diseases of various bodies and systems, first of all digestive, to-rye on the wedge, sometimes remind a current an allergic syndrome, and also with bad portability of food on the soil enzymopathies (see), psychogenic and flavoring factors. In certain cases wedge, picture P. and. reminds an acute appendicitis, impassability of intestines, fibrinferments of mezenterialny vessels. However bystry effect at use of antiallergenic means, existence of the general allergic symptoms (a small tortoiseshell, a Quincke's edema, a bronchospasm, migraine, etc.), an outcome safe in most cases allow to make the correct diagnosis.

Treatment

Treatment of food allergy complex. In the acute period in the presence of heavy a wedge, manifestations carry out nonspecific therapy (see. Acute anaphylaxis ); at the same time also use of symptomatic means is of great importance: a gastric lavage and intestines for the purpose of removal of food antigen, use of a hot-water bottle, cordial, sosudotoniziruyushchy and anesthetics, and also a complete starvation within 1 — 3 days.

Out of the period of an aggravation specific therapy is carried out. The diet — an exception of a diet of the sick products possessing allergenic influence belongs to its methods and also the sodium chloride, carbohydrates which are especially quickly soaking up — sugar, honey, jam, extractives, hot and salty dishes are limited, alcoholic beverages are prohibited. Specific desensitization at which appoint an intolerable product in gradually increasing doses is recommended. So, water soluble products (milk) part in boiled water concerning 1:2, 1:10, 1:100, 1:1000. Treatment is begun with reception of the most divorced product on 1 teaspoon once a day, then 2 — 3 times a day, daily raise a dose to 10 spoons 3 times a day, passing to cultivation 1:100 etc. The divorced product shall be in the refrigerator, and it is necessary to train him each 3 — 4 days. The course of treatment proceeds not less than 3 — 4 months. Desensitization to fish, meat, eggs and other insoluble products is carried out by the same principle. In mild cases of P. and. specific desensitization across Bezredka can be used (the patient accepts a small amount of an intolerable product, e.g. x / 4 spoons of egg, 20 — 30 ml of milk in 45 — 60 min. prior to reception of the main quantity of a product). Repeated carrying out desensitization at a number of patients leads quite often to recovery.

The technology of preparation of the food-borne allergens used for the medical purposes (desensitization), and also for the diagnostic purposes is various. For receiving antigenoaktivny fractions use sedimentation, extraction, dialysis, lyophilizing), a chromatography, dissolution, filtering, centrifuging and other ways of processing of material that allows to allocate on 4 — 6 various antigenic components from one foodstuff.

Antigenic activity polypeptide fragments of simple proteins, N-glikozidnye the centers of glycoproteins most have, but it remains also at low-molecular substances.

Prevention

Prevention of food allergy provides healthy nutrition of pregnant women, especially in families where there are allergic diseases; various food at early children's age, excepting products with the high sensibilizing influence; early and systematic treatment acute and hron, diseases of a digestive tract.

Food allergy at children

Food allergy at children meets at early children's age more often. P.'s prevalence is most studied and. to cow's milk. According to Glazer (J. Glaser, 1959), it is observed at 1 — 2% of the children's population; according to other researchers — to 7 — 7,5%. The second place on distribution is taken by a sensitization to protein of egg, the third — to fish, then — to a citrus, chocolate, nuts, cereals.

At children with allergic diathesis (see. Diathesis ) and the developed allergic diseases the number of reactions to food-borne allergens considerably raises and comes to light in 40% of cases. Development in such children of allergic reactions (immediate type) is substantially connected with the inherited ability to produce at receipt of food-borne allergens of an antibody of IgE (reagins) in much large numbers, than at healthy children. However P.'s development is possible and. at children with participation of other types of antibodies.

The greatest value has P. and. children of the first year have lives. The sensitization to food-borne allergens is possible through a placenta and went. - kish. path (main way). Predisposition to P. and. is explained by age features of digestive organs: an epithelium of intestines at children of the first year of life more pronitsay and nek-ry components of food can easily get through it in the form of the connections which kept antigenic properties. Their hypoactivity of a gastric juice is revealed, the pancreas begins to function actively only by 6th month therefore early dokorm and artificial feeding often lead to P.'s development and., especially at children with hereditary burdeness allergic diseases and displays of allergic diathesis. The sensitization to food-borne allergens, in particular to cow's milk, can be observed very much early — from first months of life. Universal distribution of artificial feeding, early administration of the mixes prepared from cow's milk are one of the reasons of bystry increase of level of a sensitization to food-borne allergens.

Development of a sensitization by foodstuff is promoted by intestinal infections, dysfunctions went. - kish. a path, to-rye lead to local disturbances of blood circulation. Inborn insufficiency of some enzymatic systems — lactoses, glyukozo-6-fosfatdegidro-genazy, intracellular enzymes of intestines can be of great importance. A part is played by insufficiency of products of secretory IgA of intestines.

The sensitization to food-borne allergens on the first year of life can be monovalent, but the polyallergy quickly develops.

The clinical picture is various and decides by localization of interaction of a food-borne allergen on an antibody. Gastrointestinal manifestations (abdominal pains, the dispeptic phenomena, dysfunctions of intestines, stomach, gall bladder), skin allergic reactions (urtikarny rashes, Quincke's disease, eczema, neurodermatitis), respiratory manifestations (rhinitis, asthmatic bronchitis, bronchial asthma), cases of an acute anaphylaxis, and also leykopenichesky, tr Ambon and iche-sky reactions meet. Quite often at children with P. and. headaches, weakness, sharply expressed fatigues and irritability are observed. At children of the first year of life a recurrent intertrigo, seborrhea, rashes of various character, damage of mucous membranes, an unstable chair are noted.

Treatment includes elimination of allergen, immunomedicinal therapy. Exclude such allergens as tomatoes, strawberry, a citrus, nuts, fish, chocolate, leaving a diet on caloric content sufficient that normal development of the child was not broken.

At all methods of specific desensitization administration of allergen begins with big cultivations, gradually it is carried to small cultivations thanks to what blocking antibodies form and tolerance is reached. However children of early age have a carrying out specific desensitizations (see) it is very complicated.

G. N. Speransky and S. G. Zvyagintseva (1958) applied at P. and. peptone and sulfur in small doses on an empty stomach. At associated diseases went. - kish. a path their treatment is necessary. In connection with reduced enzymatic activity went. - kish. path to small children with P. and. appointment salt to - you and pepsin, an abomina, panzi-norm, festal is reasonable. Antihistaminic drugs are shown.

Prevention consists in observation of children with P. and. the allergist for the solution of questions of a balanced diet, treatment, carrying out preventive inoculations. The best type of food of the baby is breast milk, on condition of healthy nutrition of the nursing mother. During the feeding by a breast introduction of a dokorm or feeding up shall be carried out carefully and in small amounts. It is better to enter milk in a powdery look, in the form of acid mixes or to replace it with drugs of soy.

With age P.'s manifestations and. decrease.

See also Allergens , Allergy .



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A. M. Nogaller; T. S. Sokolova (ped.).

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