Food allergy.

Food allergies are immunologic reactions to food allergens or food components. Several distinct clinical entities fall under this term, including immediate-in-time allergic reactions, which are IgE-dependent and involve mast cells and basophils, and delayed-in-time reactions to foods, such as food-induced enterocolitis, which involve additional effector systems. Most food allergies are precipitated by a small number of foods. The diagnosis of these diseases depends on history, physical examination, specific diagnostic assays, and oral food challenge. The differential diagnosis of these diseases is extensive. Treatment of food allergies relies on identification of the food substance that induces the reaction and subsequent avoidance measures. When an individual inadvertently consumes food to which he or she is sensitized, pharmacologic treatment is available.