Hen egg allergy is very common in infants with eczema and usually outgrown by age 6 with a few children retaining their egg allergy into adulthood. The egg white or albumin is more allergenic than the yolk and heat or cooking damages the allergen making it less allergenic. Some children will therefore tolerate cooked but not raw egg, whereas other more severely allergic children will react to all traces of egg. Early onset of egg allergy is associated with asthma at age 18 months. Fortunately the Measles (MMR) vaccine no longer contains any egg so is not contraindicated in egg allergic children. However the Influenza and Yellow Fever vaccines are grown on chick egg embryo’s and therefore may be a problem for egg allergic children.
A new ImmunoCAP f233 blood test can now determine whether hen’s egg allergy is likely to be severe and persists into adulthood. Once the IgE skin prick test or blood RAST testing show a positive allergy result for eggs, a further test for raised antibodies to the heat-stable egg protein Ovomucoid (Gal d 1) is very useful for determining if egg allergy will persist.
Ref: Ando H, Moverare R, Kondo Y et al Utility of ovomucoid-specific IgE concentrations in predicting symptomatic egg allergy. J Allergy and Clin Immunology 2008:122;583-8.
