Egg allergy

Egg allergy
Fried chicken egg
Classification and external resources
ICD-9-CM	V15.03
MeSH	D021181
[]

Egg allergy is a type of food allergy. It is a hypersensitivity to dietary substances from the yolk or whites of eggs, causing an overreaction of the immune system.

Prevention may be partly achieved through early introduction of the eggs to the diet of babies. It is usually treated with an exclusion diet and vigilant avoidance of foods that may be contaminated with egg. The most severe allergy reaction is called anaphylaxis and is an emergency requiring immediate attention and treatment with epinephrine.

Egg allergy appears mainly in children and are the second most common food allergy in children in the United States. Most children outgrow egg allergy by the age of five, but some people remain allergic for a lifetime.

Giving eggs to babies early in life appears to decrease the risk of later allergies.

Most people who are allergic to hen's eggs have antibodies which react to one of four proteins in the egg white:ovomucoid, ovalbumin, ovotransferrin, and lysozyme; ovomucoid, also called Gal d 1, is the most common target of immune system attack. The egg yolk contains several potential antigens: livetin, apovitillin, and phosvitin.

A person who reacts only to a protein in the egg yolk may be able to easily tolerate egg whites, and vice versa. Some people will be allergic to proteins in both the egg white and the egg yolk. Egg yolk allergies may be somewhat more common in adults. A small number of people who are allergic to eggs will develop an allergy to chicken or other poultry meats.

Egg whites, which are potent histamine liberators, also provoke a nonallergic response in some people. In this situation, proteins in egg white directly trigger the release of histamine from mast cells on contact. Because this mechanism is classified as a pharmacological reaction, or "pseudoallergy", the condition is considered a food intolerance instead of a true IgE-based allergic reaction.

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