Importance of chamber size for the outcome of atopy patch testing in children with atopic dermatitis and food allergy

Because the small backs of young children offer little space for atopy patch testing, it would be helpful to use smaller chambers. We therefore compared 6-mm chambers with the 12-mm chambers used in previous studies. We performed 55 double-blind, placebo-controlled food challenges in 30 children (17 boys, 13 girls) aged 3 to 58 months (median, 13 months). Sensitivity, specificity, positive predictive value, negative predictive value, and efficiency results show that the 12-mm chamber size yields much better results than the 6-mm chamber size. Therefore, 1,2-mm cups should be used for atopy patch tests with food, even in infants and small children.