Food allergy in early childhood

Etiology and clinical presentation

The leading factor in the development of food allergy in the first year of life is cow's milk protein (CMP). Key causative allergens include α-lactalbumin, β-lactoglobulin, and the casein fraction (αS1-casein). As complementary foods are introduced, the spectrum of allergens may expand.

The disease is characterized by marked symptom polymorphism. In infants, dermato-gastrointestinal syndrome predominates, including:

• Cutaneous manifestations: atopic dermatitis, erythema in natural skin folds, treatment-resistant diaper dermatitis, and various exanthems.
• Gastrointestinal disorders: regurgitation, vomiting, flatulence, unstable stools (alternation of diarrhea and constipation), as well as the appearance of pathological impurities in the stool (mucus, blood).

In older children, the clinical picture transforms: dermato-respiratory syndrome (a combination of skin and respiratory tract lesions) comes to the forefront.

Classification of foods by allergenic potential

The basis of treatment is an elimination hypoallergenic diet, implying the complete exclusion of foods with high sensitizing activity, as well as purine bases and extractive substances. All foods are divided into three groups:

1. High potential (strict elimination):
2. Animal proteins: whole cow's milk, chicken eggs, fish, caviar, any seafood.
3. Cereals: wheat, rye.
4. Vegetables, fruits, and berries (brightly colored and exotic): tomatoes, carrots, strawberries, wild strawberries, raspberries, citrus fruits, pomegranate, persimmon, melon, pineapple, kiwi, mango, bananas.
5. Other: honey, nuts, mushrooms, cocoa, chocolate.
6. Moderate potential:
7. Beef, chicken.
8. Oats, buckwheat, rice, soy, beans, peas.
9. Beets, potatoes, apricots, peaches, black currants, blueberries, cranberries, lingonberries, rose hips, dark red cherries.
10. Low potential (basis of the hypoallergenic diet):
11. Fermented dairy products.
12. Hypoallergenic meat: rabbit, turkey, horse meat, lean pork.
13. Cereals: corn, millet, pearl barley.
14. Vegetables (green/white): all types of cabbage (white cabbage, cauliflower, broccoli), zucchini, cucumbers, greens.
15. Fruits and berries (light-colored): green apples and pears, yellow plum, white/yellow sweet cherry, white/red currant.

Management tactics and nutritional support

Sensitization can occur even during exclusive breastfeeding via antigens in the mother's milk. In this case, the nursing mother is prescribed a strict elimination diet.

Important: A prophylactic hypoallergenic diet for pregnant women (even those in risk groups) is not recommended, as it disrupts the development of oral tolerance in the fetus.

If the mother's diet is ineffective, partial restriction of breast milk is used with supplementation by specialized formulas. In formula-fed infants, tactics depend on the severity of the allergy:

• Mild and moderate forms: formulas based on partially hydrolyzed protein. They are used in a 3–6 month course, followed by a return to standard adapted formulas.
• Severe forms: formulas based on extensively hydrolyzed protein or amino acid formulas (containing no intact protein). They provide a rapid effect, but their prolonged use is undesirable due to the risk of central nervous system developmental delay and impaired formation of oral tolerance.

In case of a high risk of allergy, goat's milk-based formulas can serve as an alternative, as they have a different antigenic structure that reduces the risk of cross-reactions.

Dietary features in the first year of life and beyond

The first year of life requires strict adherence to the animal protein quota — at least 90% of total protein intake. It is a critically important source of essential amino acids for the rapid development of the central nervous system.

The use of plant-based (soy) formulas is strictly limited. They lack a complete amino acid profile and may be prescribed no earlier than 5–6 months. In addition, there is a high risk of developing combined sensitization to CMP and soy proteins.

During the introduction of solid foods, the functional maturation of the gastrointestinal tract must be taken into account. The criterion for transitioning from homogenized food to textured dishes containing small pieces is the eruption of 4 teeth (usually at the age of 9–10 months).

After 1 year, breastfeeding is recommended to be continued whenever possible. For formula-fed children, the transition is made to stage 3 formulas (specialized formulas for children over one year old) which are enriched with vitamins and minerals, but contain a reduced protein quota to adapt to the child's metabolism.

Class and exam questions

What else to study on this topic

• Key CMP allergens: structure of α-lactalbumin and β-lactoglobulin.
• Immunological mechanisms of oral food tolerance development.
• Criteria for choosing between extensively hydrolyzed and amino acid formulas.
• Differential diagnosis of gastrointestinal syndrome in food allergies.

Other topics in "Chapter 3. Adaptation, Early Childhood Nutrition, Rickets"

Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.