Food allergy prevalence has increased during the last years, affecting 15-20% of children, in this case,
egg allergy affects from 0.5-2.5%. Most of the egg
allergic reactions are type I or
IgE mediated
antibodies against
egg proteins. Five major
proteins have been identified:
ovomucoid (Gal d1), ovoalbumin (Gal d2),
ovotransferrin (Gal d3),
lysozyme (Gal d4) and
albumin (Gal d5).
Ovomucoid protein, which is found in the egg white, is heat resistant and
enzyme resistant. This
protein is the most allergenic and the most common in egg composition. Clinical diagnosis requires a detailed questionnaire. Skin prick test or
Ige specific diagnosis are made as first choice. Skin prick tests are quick and useful to determine the presence of
IgE specific
antibodies to egg. Specific
IgE for egg can be measured using standarized
IgE studies in vitro, making a quantitative measure. Traditionally with the clinical history a diagnosis can be made. Standarized oral double blinded-placebo controlled challenge continues to be the gold standard for
food allergy diagnosis. The identification and elimination of
egg proteins from the diet is the primary treatment and the only one validated to this food, but there are more studies needed to stablish protocols for each specific egg
allergen before the oral inmunotherapy becomes a routine practice.