[Food allergies in early childhood. 1. General concepts, etiopathogenesis, and main clinical features].

Abnormal immune reactions to food antigens are a rather common event during infancy. Adverse reactions to milk proteins occur in 2.5% of suckling infants. Both IgE and non IgE-mediated allergic mechanisms may be involved in the pathogenesis of food allergy. IgE mediated allergic responses are the most dramatic and the most often diagnosed types. Non IgE mediated food allergy is usually more difficult to diagnose and its clinical course is more chronic. Food induced allergic reactions mediate a variety of symptoms, involving the gastrointestinal and respiratory tract and the skin. A limited number of foods are responsible for the vast majority of allergic reactions: cow milk proteins, egg, fish and peanuts are the main causes. The vast majority of infants with formula-protein intolerance will outgrow their symptoms by the third year of age. Eliminating the food allergens is the only means of dealing with the problem. In part I of this series, immunopathogenic mechanisms and clinical disorders are described.