Food allergies in infants

Food allergy in infants: Mechanisms, symptoms, and modern approach

Food allergy is an inadequate reaction of a child's immune system to proteins found in certain foods. In infants, especially during the first 6–8 months of life, this condition is fairly common due to the immaturity of both the immune and digestive systems. It is important to understand that this is not simply a \"sensitive tummy\", but a complex immunological process that requires careful diagnosis. In most breastfed children, the allergy develops to proteins that entered the milk from the mother's diet. This does not mean that feeding must be stopped, only that dietary adjustment is needed.

Why does the immune system \"mistake\"?

The basis of food allergy is a dysfunction of the immune system. An infant's gut has increased permeability, and its immune system is still \"learning\" to distinguish safe substances from harmful ones. In allergy‑prone children, the immune system mistakenly identifies certain food proteins as threats and begins producing antibodies against them (usually IgE). Upon subsequent contact with that protein, histamine and other inflammatory mediators are released, causing various symptoms.

Most common food allergens for infants:

• Cow's milk protein (CMP): This is the #1 allergen in children during the first year of life.
• Chicken eggs.
• Soy.
• Wheat (gluten).
• Nuts and peanuts.
• Fish and shellfish.

Genetics plays a key role. If parents have any allergic conditions (not necessarily food‑related), the risk of a child developing an allergy increases significantly. More details can be found in the article about infant eczema, which is often the first manifestation of allergy.

How does food allergy manifest in infants?

Symptoms can be highly varied and affect different body systems. They may appear immediately, or several hours or even days after exposure to the allergen.

• Skin manifestations (most common): Atopic dermatitis (eczema), hives, swelling of the lips or eyelids.
• Gastrointestinal manifestations: Severe vomiting, frequent regurgitation, diarrhea (often with mucus or streaks of blood), intense colic and abdominal pain.
• Respiratory manifestations (less common): Runny nose, nasal congestion, wheezing, cough.

It is important to understand that food intolerance (for example, lactose intolerance) and allergy are different conditions. Intolerance is related to enzyme deficiency and does not involve the immune system.