Challenge test is the gold standard test in egg allergy but it can cause severe reactions. It would be very useful to establish a cut–off point in skin prick test (SPT) and specific-IgE antibodies that would separate allergic from tolerant patients. The objective was to validate the SPT and the specific-IgE antibodies in children with egg allergy.

A transversal study of 30 children. A medical history, SPT and specific-IgE antibodies to egg white, egg yolk, ovoalbumin (OVA), ovomucoid (OVM), ovotransferrin and lisozime were performed. A SPT ≥3 mm and a specific-IgE antibodies ≥0,35 Ku/l were considered positive. Double-blind, placebo-controlled food challenge test (DBPCFC) with egg yolk, cooked egg white and raw egg white and complete egg boiled was done. All the parents signed up an informed written consent. The next exclusion criteria were considered:

DBPCFC in 30 children being positive in 22 (73%).

The egg white had the greatest diagnostic efficacy. Clinical history, SPT >=3 mm and specific-IgE antibodies >=1Ku/l to egg white were the cut-off points with the highest positive predictive value. SPT >=6mm to egg white had a probability 3 times higher of having a positive challenge test.