IgE-mediated food allergy--extensive review of the literature

Adverse reactions to food, i.e. food allergy and intolerance have gained considerable attention. This overview focuses on the diagnosis and management of IgE-mediated food allergy that is believed to be responsible for most immediate-type food-induced hypersensitivity reactions. Clinically, these reactions are characterised by a variety of signs and symptoms that occur within minutes or hours after consumption of the offending food. Reactions may be limited or more generalised with involvement of the skin, nose, eyes, and/or lungs. In more severe cases, cardiovascular symptoms including hypotension, shock, cardiac dysrhythmias and death can occur. In food-allergic individuals, IgE is produced against naturally occurring food components, primarily glycoproteins that usually retain their allergenicity after heating and/or proteolysis. While adults tend to be allergic to fish, crustaceans, peanuts and tree nuts, children tend to be allergic to cow's milk, egg white, wheat and soy more frequently. "Emerging" food allergens include tropical fruits, sesame seeds, psyllium, spices and condiments. These allergies frequently represent a cross-allergy to an allergen derived from another source, e.g. pollens or natural rubber latex. The evaluation of IgE-mediated food allergy relies on a careful history, physical examination, appropriate skin testing or in vitro testing with food extracts, and/or double blind, placebo-controlled food challenges. Avoidance remains the mainstay of therapy. However, allergens may be "hidden" and labelling can be non-precise or misleading, thereby severely hampering prevention. Patients with severe allergies should keep at hand an emergency kit with adrenaline, an antihistamine and an injectable rapid onset-of-action corticosteroid. At present there is no evidence to support the use of immunotherapy, except for research purposes. Production of "hypoallergenic" food is hampered by incomplete methods for assessing the allergenic potential of such novel foods.