Prevention of food allergies in children at risk of developing atopy

Food allergies in children are the body’s response to eating a certain food. The most common type of response is that mediated by antibodies of the Ig E type. There is a cell-mediated immunological response that occurs later. An atypical condition is accompanied mainly by atopic dermatitis or disorders of the digestive system.

On the other hand, food can also cause a reaction if it comes into contact with the skin or comes into contact with the respiratory tract. In the first case, this can lead to dermatitis and urticaria; in the second - to problems associated with the respiratory system (asthma or rhinitis).

Types of food allergies

Currently there are several types:

1. For the white of a chicken egg. It develops during the production of Ig E immunoglobulins in the body, directed against egg whites. The most common risk factor is hereditary predisposition. Occurs mainly between the ages of 1 and 5 years. Characterized by redness of the skin, itching, hives, swelling of the lips and eyelids. Vomiting, abdominal pain and diarrhea may occur. Less commonly, respiratory manifestations occur, which may be accompanied by shortness of breath and difficulty swallowing. They are very serious, so the patient should see a doctor the moment they begin to occur.

2. For fish and seafood. Established by an immune response mediated by Ig E - antibodies specific to fish. It is observed in the first years after birth and coincides with the introduction of fish into the diet. May persist for decades or a lifetime. Symptoms appear after consumption and when inhaling fumes generated during cooking.

3. For milk. It has a hereditary basis, although environmental factors also participate in its development. Characteristic mainly in the first year of life. The severity of the clinical picture depends on the degree of sensitization and the amount of milk consumed. The most common manifestations are skin (70% of cases). There may also be abdominal pain, loose stools, vomiting, or trouble swallowing.

4. For vegetables and fruits. The most common cause is in patients over 5 years of age. About 33% of children cannot tolerate fruits and only 7% cannot tolerate vegetables. It manifests itself as itching, swelling of the lips and tongue, the appearance of red spots or scars on the skin, and dermatitis. Signs from the gastrointestinal tract and respiratory system may also appear.

5. For nuts, legumes and grains. In 50% of cases, the reactions are so severe that they can even lead to death. This species is the most dangerous when compared with others, because it develops at lightning speed.

Basics of disease prevention

Prevention begins during pregnancy, when it is necessary to avoid any allergens. If you suspect an allergy, you should consult a doctor - he may prescribe medications. The expectant mother should give up strawberries, citrus fruits, soy, fish, eggs, dairy products, and gluten.

When the baby is born, the nutrition of the nursing mother is important. It is necessary that she continue to follow the diet and not abuse the products listed above.

When selecting a mixture, a number of factors are taken into account:

• it should not contain cow's milk;
• children at risk are shown preventive and even therapeutic mixtures;
• When consuming goat and cow's milk, there can be a cross-allergy, so goat's milk should also be excluded.

If an older child is diagnosed with a food allergy, then you need to find out exactly what the immune reaction is to. The allergen must be removed from the diet, and also try to adhere to a gentle diet, that is, eliminate the potential allergens that we discussed in the “Treatment” section.

Causes

A child develops a food allergy due to:

• genetic predisposition;
• decreased protective functions of the intestinal mucosa;
• large amounts of food consumed, etc.

In circumstances where tolerance fails, the immune system produces an Ig E antibody response against the specific food. The process begins in the intestines (although it can also affect other areas, such as the respiratory system or skin).

When a patient consumes a “dangerous” product, the antigen associated with Ig E is detected on the surface of basophils and mast cells. At this time, they are activated, and histamine and other inflammatory substances are released.

Content

• Causes of food allergies Products that most often cause allergies

A food allergy is an increased sensitivity of a child’s body to any harmless food or ingredient.

In most cases, the cause of allergies is heredity. But at the same time, parents may be allergic to some foods, and the child may be allergic to others.

Allergies occur when the body produces antibodies to dietary proteins found in certain foods. An acute reaction can be life-threatening. However, most manifestations are mild. There are three most “allergic” food groups:

• Milk. This is the most common cause of food allergies in young children. Out of 100 children, every second or third cannot tolerate cow's milk. However, by age 4, 95% outgrow this intolerance. Source: R. F. Khakimova On the issue of food allergies in children Practical Medicine, May 2009, 3(35)
• Chicken egg white, crustaceans, nuts. They are in second place among the causative agents of allergies. Usually the disease does not disappear with age, but remains for life.
• Peanut. The most famous allergen. Peanuts are not a nut, but a legume, so often children who react to them do not have a negative response to cashews, almonds, etc.

Symptoms of food allergies in children

It appears in the first two hours after eating if the diet includes a dangerous factor. One or more organs are affected, including the skin, gastrointestinal tract, mucous membranes, respiratory and cardiovascular systems. The severity of the course depends on the reactivity of the affected organ, the general well-being of the patient and the characteristics of the factor causing the atypical response.

Main features:

• Skin manifestations. Urticaria is the appearance of a small rash. Accompanied by redness, itching and peeling. It is localized mainly on the face and neck, hands, forearms and elbows. It may become complicated when a bacterial infection occurs.
• Respiratory manifestations. Rhinitis is accompanied by nasal congestion, profuse watery discharge and repeated sneezing. In rare cases, a sore throat and coughing may occur.
• Airway involvement. In patients with asthma, bronchospasm may be present in the context of anaphylaxis (severe systemic condition). Anaphylaxis is dangerous because, if left untreated, it can be fatal.
• Damage to the gastrointestinal tract. Accompanied by diarrhea, abdominal pain, nausea and vomiting. The stool undergoes changes and most often becomes liquefied.

Other symptoms include itching in the mouth and throat, as well as in the eye area. Possible difficulty swallowing, dizziness, fainting, swelling of the eyelids, face, lips and tongue.

What are the reasons for the development of food allergies in children of the first year of life?

Firstly, the reasons may be a violation of the gastrointestinal tract (GIT). When a baby is born, most of its organs are at the “ripening” stage. For example, the production of enzymes in the gastrointestinal tract is reduced. That is, the pancreas has not yet learned to produce in the required quantities such enzymes as trypsin (necessary for the breakdown of proteins), amylase (for the breakdown of carbohydrates), lipase (for the breakdown of fats), gastric juice contains few proteases (break down protein), etc. .

In addition, the composition of the microflora in newborn babies is disturbed. More precisely, it has not yet fully formed. Thus, it turns out that many large molecules (what any food product consists of), once in the tummy of a newborn baby, simply cannot be digested. That’s why we don’t feed babies up to a certain age with fruits, cottage cheese and meat. What happens to these molecules? Due to the increased permeability of the intestinal mucosa (also a feature of the newborn), these molecules penetrate into the blood vessels (they permeate all the intestinal walls). They produce antibodies called IgE. “Sensitization” occurs - increased sensitivity to certain macromolecules. That is, the body became acquainted with these macromolecules, developed antibodies, and the next time they met, the antibodies would react to the re-entry of the same macromolecules. An allergic reaction will develop. Food sensitization can develop from the first days or months of a child’s life.

Risk factors for the development of allergic reactions in children may be hereditary predisposition and environmental problems (primarily maternal smoking during pregnancy). Preeclampsia in the mother (and therefore hypoxia - oxygen starvation - of the fetus) and infectious diseases suffered by the mother during pregnancy (and antibiotic treatment carried out in connection with this) also play a negative role.

What nutritional disorders of mother and child can lead to the development of food allergies?

Firstly, it is the nursing mother’s excessive consumption of cow’s milk, cottage cheese, and highly allergenic foods (chocolate, nuts, strawberries, oranges, red fish and caviar). Secondly, early transfer of the child to mixed or artificial feeding, especially with the use of unadapted milk formulas and the administration of whole cow's milk in the first year of the child's life (as the main food product). Clinical manifestations of food allergies are extremely varied :

• Allergic skin lesions (atopic dermatitis, Quincke's edema, urticaria, strophulus - infantile pruritus).
• Gastrointestinal disorders (regurgitation, nausea, vomiting, colic, flatulence, diarrhea, constipation, unstable stool).
• Respiratory disorders (bronchial asthma, allergic rhinitis).

Studies have shown that in children of the first year of life who suffer from allergies, hypersensitivity to cow's milk proteins is most often detected (85%). Moreover, it is known that among children in the first year of life, an allergy to cow's milk proteins occurs in 0.5-1.5% of breast-fed infants, and up to 2-7% in bottle-fed infants. Among patients with atopic dermatitis, 85-90% of children are allergic to cow's milk proteins.

Also, babies have a high sensitivity to chicken egg protein (62%), gluten (53%), banana proteins (51%), and rice (50%). Less common are sensitization to buckwheat proteins (27%), potatoes (26%), soybeans (26%), even less often to corn proteins (12%), various types of meat (0-3%). It should be noted that the majority of children (76%) have polyvalent sensitization, that is, an allergy to three or more food proteins.

Products with different allergenic potential:

Diagnostics

As early as possible, it is necessary to establish and eliminate the cause of the disease - allergenic products . To do this, the allergist collects an allergic history (finds out who and what in your family had an allergic reaction), instructs you to keep a food diary (gradually reintroducing all foods, write down what the baby ate - what kind of reaction, after 3-5 days new product, etc.). Skin tests can be performed to accurately determine the allergen. They make cuts on the skin, drop “its own” allergen onto each one and wait to see what the reaction will be. This study is carried out only in the remission phase (not the acute phase) against the background of an elimination diet (from “elimination” - exception) - only low-allergenic foods are consumed.

In the acute period of the disease, the most accessible tests for diagnosing food allergies are immunological methods. They are called RAST, PRIST, MAST, ELISA. These studies are carried out in vitro (in a test tube) and allow the determination of specific antibodies (IgE and IgG4 classes) in the blood. The use of these laboratory diagnostic methods makes it possible to detect food hypersensitivity in young children, including infants, to the proteins of the most common foods: cow's milk, chicken eggs, fish, peanuts, soy and wheat.

An open oral provocation test with “suspected allergens” can be performed (carried out only when clinical remission is achieved). This test is good for its reliability, but is dangerous (up to the development of anaphylactic shock) and therefore can only be performed in specialized clinical centers.

Against the background of food allergies, hypersensitivity to other types of allergens (other food products, pollen, dust, herbal medicines, etc.) often develops. This is due to the similarity of the antigenic structure and the development of cross-reactions. That is, our body confuses 2 allergens that are similar in structure (antigenic structure). In this case, the antibodies developed to the first allergen (potato) begin to react to another allergen (tomato). This is called "cross-reaction". As a result, an allergic reaction to another product develops.

Possible cross-reactions between different types of allergens:

Diet therapy is the basis of treatment for children with food allergies

The basic principles of constructing a hypoallergenic diet are the elimination (exclusion) from the diet of foods with high sensitizing activity, causally significant, cross-reacting, irritating the mucous membrane of the gastrointestinal tract, containing preservatives, food colorings, emulsifiers, stabilizers, etc. and adequate replacement of excluded products with natural ones and specialized products.

Hypoallergenic industrial products:

• specialized mixtures based on milk protein hydrolysates (medicinal, therapeutic and prophylactic purposes, which can be consumed from birth);
• specialized mixtures based on soy protein isolate (consumed mono from 6 months of age);
• hypoallergenic dairy-free porridges;
• hypoallergenic monocomponent berry, fruit and vegetable purees (from 5-6 months);
• hypoallergenic monocomponent canned meat: horse meat, turkey, lamb, etc. (from 9-10 months);
• specialized water for baby food.

Despite the fact that an allergy to cow's milk proteins can be detected in children who are breastfed, it is important to preserve mother's milk as completely as possible in their diet, which, in addition to the main nutrients, vitamins and minerals, contains the protective factors necessary for the adequate development of the child (secretory IgA), hormones, enzymes, growth factors. Nursing mothers need to follow a special diet.

Products and dishes excluded, limited and used in hypoallergenic diets for nursing mothers:

Currently, for hypersensitivity to cow's milk proteins, mixtures prepared on the basis of milk protein hydrolysates (casein and whey proteins) are widely used.

Distribution of mixtures based on hydrolysates depending on their clinical purpose:

A positive effect should be expected no earlier than 3-4 weeks from the start of using specialized mixtures.

It is important to note that the level of tolerance (“resistance”, absence of allergy) to cow’s milk proteins (CMP) is achieved in 80-90% of children by the age of 3 years, but 10-20% of children cannot tolerate CMP at the age of 3 years, and in 26% manifestations of milk allergy can persist for up to 9-14 years.

When introducing complementary foods, it is necessary not to rush into deadlines and strictly follow all the rules of complementary feeding. This is a gradual introduction (starting with 1/4 tsp), we introduce only 1 product for 5-7 days, and only then try to introduce the next one.

Timing for introducing complementary foods to children in the first year of life with food allergies (compared to healthy children):

*Taking into account individual tolerance of products

Possible complications

The danger is that this condition gradually worsens if no measures are taken over time:

1. First, against the background of sensitization, the body develops dermatitis.

2. Then the respiratory system is damaged in the form of atopic rhinitis.

3. If the antigen is not excluded, then bronchial asthma manifests itself.

The most dangerous complication is anaphylactic shock. It develops rapidly – ​​1-3 minutes after contact with the antigen. It is characterized by bronchospasm, laryngeal edema and collapse, which can be fatal if not treated promptly.

How dangerous the disease is: possible complications

In children under one year old, allergies combined with vomiting and diarrhea lead to severe dehydration, which is extremely dangerous for babies. Anaphylactic shock, Quincke's edema, suffocation, and bronchospasm are also possible. All of these conditions are potentially fatal at any age.

Sources:

1. R F. Khakimova. On the issue of food allergies in children // Practical Medicine, May 2009, 3(35)
2. A.N. Pampura, O.V. Yudina, Yu.G. Mukhina, M.G. Ipatova. Achievements and problems in diagnosing food allergies in children // Difficult Patient, 2007, vol. 5, no. 10
3. O.V. Trusova, I.V. Makarova, A.V. Kamaev, N.L. Lyashenko. Nutrition of children with food allergies // Pediatrician, 2021, v. 8, special issue

Grek Elena Anatolyevna Clinic

Author of the article

Grek Elena Anatolyevna

Doctor of the highest qualification category

Specialty: allergist

Experience: 23 years

The information in this article is provided for reference purposes and does not replace advice from a qualified professional. Don't self-medicate! At the first signs of illness, you should consult a doctor.

Diagnosis of food allergies in children

In many cases, people confuse a specific reaction of the body with individual intolerance. There are definitely some similarities between them, but we are talking about different pathologies. Excessive sensitivity appears after eating as a response of the body, while with intolerance the protective functions do not interfere. The main causes of intolerance are usually metabolic disorders of certain substances.

If signs of hypersensitivity appear, you should immediately consult a doctor. The specialist will take a detailed medical history to try to determine which factors are “dangerous” and establish a temporal relationship between food intake and the appearance of symptoms.

Skin tests can sometimes help diagnose a specific reaction. A positive result does not necessarily mean that sensitivity is present, but a negative result indicates that the patient is unlikely to be sensitive to such food. After receiving a positive skin test, an allergist may need to perform oral monitoring to make a definitive diagnosis.

Methods for diagnosing the disease

To make an accurate diagnosis, the doctor examines the medical history and conducts laboratory tests.

Tests to detect food allergies:

• skin tests (scarification test, prick test, patch test);
• immunological methods (RAST, ELISA). Source: A.N. Pampura, O.V. Yudina, Yu.G. Mukhina, M.G. Ipatova Achievements and problems in diagnosing food allergies in children // Difficult Patient, 2007, vol. 5, no. 10

At SM-Clinic you can undergo all these studies and get results in the shortest possible time.

There are contraindications to performing skin tests:

• exacerbation of an allergic disease;
• taking antihistamines (the test will be non-indicative);
• if the child has ever experienced anaphylactic shock.

Treatment of food allergies

Currently, the only remedy against the negative effects of the provoking factor is the exclusion of the dangerous substance from the diet. This recommendation seems simple, but far from reality. A proper diet requires constant monitoring to avoid exposure to present and hidden antigens that appear in processed foods. It is recommended to study the composition when dishes are prepared outside the home to avoid accidental contact with antigens. Unfortunately, not everyone succeeds in eliminating contact.

In recent decades, special treatment methods have begun to be developed aimed at changing the immune response and acquiring oral tolerance. These methods are known as oral desensitization or allergy vaccines, which may show promise for specific reactions to milk, peanuts, and eggs. To get individual treatment recommendations, contact your pediatrician or allergist.

Prevention measures

Complete recovery is possible only with early identification of factors and their exclusion from the diet. By following nutritional recommendations, relapses of the disease can be prevented. Some children experience spontaneous recovery as oral tolerance increases. Many people “outgrow” the disease, but you shouldn’t count on it.