Allergic enteropathy is an inflammatory disease of the small intestine of an allergic nature that occurs when antigens enter the body that cause an excessive, increased reaction of the immune system. Most often, the disease develops in young children. Allergic enteropathy is manifested by diarrhea, bloating, intestinal colic, regurgitation, insufficient weight gain. Diagnostics includes an examination by a pediatrician and an allergist-immunologist, laboratory tests and allergological tests, intestinal examination. Treatment consists in stopping contact with the allergen, prescribing a hypoallergenic diet, antihistamines.
52.2 Allergic and alimentary gastroenteritis and colitis
Allergic enteropathy –gastrointestinal form of food allergy) is a lesion of the mucous membrane of the small intestine when allergens enter the gastrointestinal tract. Most often, the disease occurs in young children and is associated with the appearance of hypersensitivity to cow’s milk proteins, soy and other products used in the introduction of complementary foods and the transition from breastfeeding to artificial.
The prevalence of food allergies among children under the age of 3 years is about 6-8%, in 10-15 years – 3-4%. At the same time, hypersensitivity to cow’s milk protein was detected in 2-2.5% of young children, to chicken protein – in 1-1.5%. As a rule, along with allergic enteropathy, children have signs of allergic damage to other organs and systems (skin, respiratory tract, etc.).
There are more than 170 known products that, upon penetration into the gastrointestinal tract, can cause the appearance of a gastrointestinal form of food allergy (allergic enteropathy), and their allergic activity is due to the presence of animal or vegetable proteins, glycoproteins, less often polypeptides.
In children under one year of age, allergic enteropathy in most cases is caused by hypersensitivity to cow’s milk protein, which contains more than ten antigens, of which the most active are aS1-casein and γ-casein. In school-age children and adults, the development of allergic reactions with intestinal damage is more common when eating chicken egg protein, fish and seafood. The immune system often reacts to dietary fiber of plant origin entering the body: wheat, rye, oatmeal, buckwheat and rice groats, soy, as well as some vegetables (carrots, celery, tomatoes) and fruits (bananas, citrus fruits).
In the development of food allergies in children and adults, an essential role of hereditary predisposition is undeniable. This is evidenced by the presence of allergic diseases in the relatives of the patient, as well as common manifestations of allergies with skin lesions, bronchopulmonary system and the detection of hypersensitivity not only to food, but also to plant pollen, house dust, medicines and other allergens.
In the occurrence of allergic enteropathy, a decrease in the barrier function of the gastrointestinal tract (due to enzymatic insufficiency), a violation of IgA production also plays a role. Allergic reactions that develop when food antigens enter the gastrointestinal tract can be IgE-mediated, non-IgE-mediated, immunocomplex and cell-mediated. Allergic intestinal lesions are characterized by non-IgE-mediated (with proctocolitis) and cell-mediated (with allergic enteropathy) reactions.
Gastrointestinal allergy is manifested both by local signs of gastrointestinal tract damage (vomiting, intestinal colic, diarrhea) and various extra-intestinal manifestations of allergy (atopic dermatitis, eczema, bronchial asthma). The severity of the manifestation of certain clinical symptoms of the disease will vary depending on the age of the patient.
In young children, allergic intestinal damage is manifested by cramping abdominal pains of the type of intestinal colic, regurgitation and vomiting, bloating, loose stools 5-6 times a day. Sometimes intestinal bleeding may occur with a change in the color of feces. The general condition of the child is disturbed: anxiety appears, general weakness, pallor of the skin, sleep disorder, appetite, hypotrophy. Often allergic enteropathy at this age is accompanied by skin manifestations of the type of atopic dermatitis (dry damaged skin, polymorphic rash).
Timely elimination of the allergen from the diet leads to the cessation of symptoms after 2-3 days. If an allergic gastrointestinal lesion is caused by hypersensitivity to cow’s milk casein, the manifestations of enteropathy usually disappear by 2-3 years of life, even with regular consumption of dairy products.
In school-age children, adolescents and adults, the picture of the disease becomes more erased and is characterized more often by dull pain in the navel area, flatulence, unstable stool (constipation or diarrhea), decreased appetite, nausea. Extra-intestinal manifestations of allergies are rare. At the same time, allergens that cause allergic enteropathy at this age can sometimes be not only food products, but also medications, plant pollen, household dust, etc.
Clinical manifestations of allergic enteropathy are nonspecific and occur in gastroenteritis and enterocolitis of various etiologies (including those caused by infectious agents of viral and bacterial nature, helminths, protozoa, alimentary factors, poisoning with chemicals, inedible and poisonous products). To establish the correct diagnosis, it is necessary to carefully collect an allergological history, conduct a clinical examination of the patient (consultation of an allergist-immunologist, gastroenterologist), perform the necessary laboratory and instrumental studies.
The analysis of the allergological history makes it possible to identify the presence of hereditary burden (allergic diseases in relatives). As a rule, a sick child had skin or respiratory allergy symptoms observed earlier or present at the time of examination. The appearance of clinical signs of allergic enteropathy (abdominal pain, vomiting, diarrhea) is associated with the ingestion of a food allergen (cow’s milk, eggs, fish, peanuts, etc.). The condition improves significantly after the exclusion of a problematic food product from the diet.
In a laboratory study, eosinophilia (an increase in the number of eosinophils) is detected in the blood test. Fecal analysis (coprogram) reveals an increased content of erythrocytes, eosinophils, neutrophils. Histological examination of biopsies of the mucosa of the small intestine reveals signs of inflammation (edema and hemorrhage), infiltration of its own plate by lymphocytes, mast and plasma cells. In some cases, partial atrophy of the villi is detected. When conducting a specific allergological study, the content of total IgE, as well as specific IgE and IgG is determined, skin allergy tests with a set of food allergens are used.
Differential diagnosis of allergic enteropathy is carried out primarily with gluten enteropathy, in which there are no extra-intestinal manifestations of allergy, antigliadin IgA antibodies and antibodies to transglutaminase are detected.
Therapeutic measures include allergen elimination and the appointment of a hypoallergenic diet, the use of antihistamines and anti-inflammatory drugs, enterosorbents, enzymes and membrane stabilizers, symptomatic treatment of individual manifestations of the disease.
If breastfeeding is carried out, it is necessary to draw up a strict hypoallergenic diet for the mother with the exception of potential food allergens and individually intolerant foods. Children who are on artificial feeding are prescribed special therapeutic mixtures with whey and casein protein hydrolysates, as well as mixtures based on goat’s milk. The timing of the introduction of complementary foods to children with allergic enteropathy is postponed to 5-6 months of life, while hypoallergenic cereals (buckwheat, rice, corn), single-component vegetable purees, meat (veal, horse meat, pork, rabbit, turkey) are used. Cow’s milk, cottage cheese, fish and eggs are completely abandoned in the first year of life, peanuts are excluded for up to three years. Older children and adults follow an individually selected hypoallergenic diet for at least six months.
From antihistamines in the first year of life, it is recommended to use dimethinden (in drops), chloropyramine (in tablets), cetirizine (in drops), as well as ketotifen. Loratadine can be used from a year old, and fexofenadine hydrochloride and ebastine can be used from six years old. Enterosorbents are usually applied for one to two weeks during the period of exacerbation. According to the indications, enzymes (pancreatin), preparations containing bifidobacteria and lactobacilli, symptomatic agents (defoamers, antiemetics) are prescribed.
Prognosis and prevention
Switching to an elimination diet leads to regression of enteropathy symptoms. Serious health consequences usually do not develop. Prevention of allergic enteropathy consists in the observance by a pregnant and nursing mother of a hypoallergenic diet, breastfeeding up to 4-6 months of life, the introduction of complementary foods to the child no earlier than the fourth month of life, the exclusion of potential allergens from the diet at an older age and in adults.