Food allergy

Food allergies are very difficult to bear due to the fact that the allergen, entering the body, has a strong depressing effect on almost all organs and systems. Moreover, the time spent on finding the allergen leads to a delay in the allergic process, which in turn leads to the addition of many secondary diseases. Therefore, it is very important to know the symptoms of food allergies and be attentive to any of their manifestations.

The earliest manifestations of allergic reactions are observed in the first year of a child's life and are associated either with errors in the mother's diet or with the transition to a new type of food for the child. Food allergies develop both to artificial milk formulas and to natural cow's milk. When introducing complementary foods, you need to be careful with carrots, eggs, and many berries. Citrus fruits are a special highly allergenic group.

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Causes of food allergies

Food allergies are caused by substances with high allergenic properties, and these can be: animal proteins and vitamins, especially group C. All products that contain the listed components are automatically classified as a "risk group". Fish, caviar and seafood, egg and milk proteins, all red berries, citrus fruits, and even carrots can fall under the concept of "allergen". For a weakened organism, with reduced protective functions and a predisposition to allergic reactions, anything can be an allergen, even rye bread. Therefore, any case of manifestation of such a condition as food allergy should be approached individually and comprehensively.

Food allergy should be distinguished from nonimmune reactions to food (eg, lactase intolerance, irritable bowel syndrome, infectious gastroenteritis) and reactions to food additives (eg, monosodium glutamate, metabisulfite, tartrazine), which cause most food reactions. The prevalence ranges from less than 1% to 3% and varies with geography and detection methods; patients often confuse intolerance with allergy. Normal digestion prevents the development of symptoms of food allergy in adults. Any food or food additive may contain allergens, but the most common allergens in infants and young children are milk, soy, eggs, peanuts, and wheat, and the most common allergens in older children and adults are tree nuts and seafood. Cross-reactivity between food and nonfood allergens exists, and sensitization may occur nonenterically. For example, patients with oral allergy (itching, erythema, swelling of the oral mucosa after eating fruits and vegetables) may have been sensitized by pollen; children with peanut allergy may have been sensitized by creams applied topically to treat rashes that contain peanut oil. Patients with latex allergy are usually allergic to bananas, kiwi, avocado, or combinations of these foods. Allergy to latex dust in food, left by workers' latex gloves, can easily be confused with food allergy.

In general, food allergies are mediated by IgE, T cells, or both. IgE-mediated allergies (eg, urticaria, asthma, anaphylaxis) have an acute onset, usually developing in infancy, and are most common in individuals with a family history of atopy. T-cell-mediated allergies (eg, food protein gastroenteropathy, celiac disease) have an insidious onset and are chronic. IgE- and T-cell-mediated allergies (eg, atopic dermatitis, eosinophilic gastroenteropathy) have a delayed onset and are chronic. Eosinophilic gastroenteropathy is an uncommon disorder characterized by pain, cramping, diarrhea, eosinophilia in the blood, eosinophilic infiltrates in the intestinal wall, protein loss, and a history of atopic disorders. Rarely, IgG-mediated cow's milk allergy has been observed in infants, leading to pulmonary hemorrhages (pulmonary hemosiderosis).

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Symptoms of food allergies

Symptoms and objective data vary greatly depending on the allergen, mechanism, and age of the patient. The most common manifestation in infants is atopic dermatitis alone or with gastrointestinal symptoms (nausea, vomiting, diarrhea). In older children, the signs change and they react more to inhalant allergens with symptoms of asthma and rhinitis (atopic course). By the age of 10, patients rarely develop respiratory symptoms after ingestion of allergens with food, even if skin tests remain positive. If atopic dermatitis persists or first appears in older children and adults, it is obviously not IgE-mediated, even if the serum IgE level is higher in patients with severe atopic dermatitis than in those without it.

Older children and adults exposed to food allergens tend to have more severe reactions (eg, exfoliative urticaria, angioedema, even anaphylaxis). In a small number of patients, food (especially wheat and celery) is the trigger for anaphylaxis immediately after ingestion; the mechanism is unknown. Some patients experience food-induced or food-exacerbated migraine, as demonstrated by blind oral provocation tests. The most common comorbidities associated with food allergy are cheilitis, aphthous lesions, pylorospasm, spastic constipation, anal itching, and perianal eczema.

The first signs of food allergy begin to appear within a few minutes after the allergen enters the digestive system. It often happens that the delay in the symptomatic picture stretches out for several hours. Although much more often, food allergy manifests itself instantly. It proceeds according to several principles:

• skin dermatitis or urticaria;
• rhinitis;
• intestinal dyspeptic disorders;
• Quincke's edema;
• anaphylactic shock.

The last two principles of rapid development, in cases of food allergies, are very rare, only when the child's body is very weakened. Most often, food allergies cause skin reactions and gastrointestinal disorders.

There is a complex form of food allergy - cross-allergy, which occurs at once to several allergens belonging to different groups. For example, there may be a food allergy to carrots, which occurs according to the principle of dermatitis. To relieve itching and rash, the herb celandine is used in the form of a decoction, which is added when bathing. As a result, an even greater number of allergic symptoms are obtained. This is a variant of the development of cross-allergy. In this example, the allergens are carrots and celandine.

Diagnosis of food allergies

It is very useful for pregnant women to get into the habit of keeping a food diary, which will reflect the main products consumed throughout the pregnancy. With the birth of the child, the records of the mother's diet continue, and data on those products that are starting to be included as complementary food for the child are added there. Having such a diary will significantly ease the situation if a food allergy appears and it will not be difficult to determine the allergen. With or without a diary, express tests are carried out to establish an accurate diagnosis, an allergological anamnesis is collected, several allergological tests are taken.

Severe food allergies are easier to diagnose in adults. In the absence of obvious symptoms, as well as in most children, diagnosis is difficult, and such digestive disorders must be differentiated from functional gastrointestinal disorders.

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Food Allergy Treatment Methods

The main objective of treatment is to eliminate the cause that causes food allergies and further eliminate the entry of this type of allergens into the body. A course of treatment is carried out with antihistamines, with the simultaneous intake of sorbents, which help quickly remove allergic toxins from the body, while enhancing the effect of antihistamines.

A strict diet that excludes even the slightest content of products belonging to the "allergenic risk group". Food allergies are also treated with immunostimulants, which are prescribed to increase the body's resistance functions.

When a diagnosis of food allergy is suspected, the relationship of symptoms to food intake is assessed using skin or IgE-specific radioallergosorbent tests. Positive test results do not prove clinically significant allergy, but negative results exclude it. If skin test responses are positive, the food is removed from the diet; if symptoms begin to subside, the patient is advised to eat the food again (preferably in a double-blind test) to see if symptoms reappear.

An alternative to skin testing is to remove foods that the patient believes cause allergic symptoms, prescribe a diet of relatively nonallergenic foods, and eliminate the usual allergens. No other foods should be consumed except those recommended. Pure foods should be used. Many commercially prepared foods contain undesirable substances in large quantities (e.g., commercially produced rye bread contains wheat flour) or in trace amounts: flour for dusting or fat for baking or frying, making it difficult to identify the undesirable products.

Allowed foods in elimination diets ¹

Product	Diet No. 1	Diet #2	Diet #3
Cereals	Rice	Corn	-
Vegetables	Artichokes, beets, carrots, lettuce, spinach	Asparagus, corn, peas, zucchini, green beans, tomatoes	Beets, lima beans, potatoes (white and sweet), green beans, tomatoes
Meat	Mutton	Bacon, chicken	Bacon, beef
Flour products (bread and biscuits)	Rice	Corn, 100% rye (regular rye bread contains wheat)	Lima beans, potatoes, soybeans
Fruits	Grapefruit, lemon, pear	Apricot, peach, pineapple, plum	Apricot, grapefruit, lemon, peach
Fats	Cottonseed, olive oil	Corn, cotton	Cotton, olive
Drinks	Black coffee, lemonade, tea	Black coffee, lemonade, tea	Black coffee, lemonade, juice of permitted fruits, tea
Other products	Cane sugar, gelatin, maple sugar, olives, salt, tapioca pudding	Cane sugar, corn syrup, salt	Cane sugar, gelatin, maple sugar, olives, salt, tapioca pudding

¹ Diet No. 4: If the patient follows one of the proposed diets, and the symptoms do not disappear, then following this diet is questionable, and it is necessary to limit yourself to basic foods.

If no improvement is observed within one week, another diet should be used. If symptoms subside, one new product is added in large quantities for more than 24 hours or until symptoms recur. In another method, the patient takes a small amount of the new product being tested in the presence of a doctor, and the patient's reaction is recorded. An increase or relapse of symptoms after taking a new product is the best confirmation of an allergic process.

When evaluating the effectiveness of an elimination diet, the physician should take into account that food sensitization may resolve spontaneously. Neither oral desensitization (complete removal of the allergen for a period of time, followed by administration in very small amounts with a daily small increase in the portion) nor sublingual tablets with food extracts have been proven effective. Antihistamines are of limited value, except for acute generalized reactions with urticaria and angioedema. Oral cromolyn has been used successfully. Long-term glucocorticoid therapy is used in symptomatic eosinophilic enteropathy. The use of humanized monoclonal IgG1 antibodies directed against the SN3 region of IgE shows good results in the treatment of peanut allergy.

Prevention of food allergies

There is no set of measures, strictly adhering to which, you can forever protect yourself from such an unpleasant condition as food allergies. But there are basic rules for maintaining a healthy lifestyle, the observance of which helps the body "get used to" independently fighting any negative factors coming from the external environment. From an early age, it is useful to harden, play sports and eat not only meat, but also vegetable dishes, among which much attention should be paid to fresh vegetables. Diversifying your diet with porridge from different grains and cereals, taking vitamin complexes during the off-season - that's all you need to ensure that the body receives all the necessary tools, both for building strong walls of organs, blood vessels and tissues, and for resisting threats.

Food allergies, in light of the low environmental indicators of the environment and the high content of chemicals in food products, are, unfortunately, not uncommon. However, with careful attention to your health, timely visits to doctors, you can not only avoid serious manifestations of any allergic reactions, but also completely avoid encountering them.