Allergy and Asthma: Food Allergies.

Food allergies are immune-mediated allergic adverse reactions that occur after exposure to specific foods. The most commonly recognized food allergies are immunoglobulin E (IgE)-mediated reactions (eg, urticaria, angioedema, anaphylaxis) that result from exposure to milk, egg, peanut, tree nuts, shellfish, fish, wheat, or soy. However, other foods can cause food allergies. Oral allergy syndrome is a common but underrecognized condition characterized by transient oropharyngeal symptoms that result from ingestion of uncooked fruits or vegetables. Non-IgE-mediated food allergies manifest with more delayed symptoms than IgE-mediated food allergies, and predominately cause gastrointestinal symptoms. Food allergies often are overreported because they may be confused with food intolerances or nonimmunologic adverse food reactions (eg, lactose intolerance, food poisoning, caffeine intolerance). Food allergies are diagnosed using IgE skin tests, IgE serum tests, or oral food challenge tests. These allergies are best managed by avoidance of the food or foods related to the allergy because they require ingestion rather than contact to precipitate symptoms. Injectable epinephrine should be prescribed for patients at risk of anaphylaxis. Careful food label reading and food preparation, awareness, and education are keys to prevention.