Eliciting doses of positive challenge test in cow's milk allergy are related to cow's milk specific IgE levels

Abstract

BackgroundIngestion of small amounts of cow's milk (CM) can elicit adverse reactions in patients with IgE-mediated CM allergy. Knowing the dose eliciting allergic reactions and the factors affecting it can be of great help in avoiding these reactions. ObjectiveTo analyse the eliciting doses of positive challenge test in patients with CM allergy and to determine its association with the level of CM specific IgE. MethodsNinety-eight positive challenge tests in 56 children, median age of 11 months (3-80) with IgE-mediated CM allergy were retrospectively analysed. Open oral challenge tests were carried out by gradually increasing doses of milk (2-100ml). The relationship between challenge test doses and CM specific IgE levels were studied. Results18 % of the challenge tests were positive with 2ml, 24 % with doses between 5 and 10ml, and the other 58 % with doses between 25 and 100ml. An inverse association between the doses of the positive challenge test and the level of CM specific- IgE was found, 13.9kU/L (0.54−>100kU/L) when the challenge test was positive with the smaller dose (2ml); and 1.73kU/L (<0.35− 76.4kU/L) with doses above 2ml (p=0.0001). The median age of the patients was 13 months (6-49) when the challenge test was positive with 2ml vs 9 months (3-80) with doses above 2ml (p=0.048). ConclusionThe CM specific IgE level and patient's age should be considered in the assessment of the eliciting doses of positive challenge test in CM allergy.