Atopy patch test in children with atopic dermatitis

Abstract

BackgroundAtopic dermatitis is frequently associated with food and/or aeroallergen allergy. ObjectiveTo evaluate atopy patch tests (APTs) and skin prick tests (SPTs) in children with atopic dermatitis, using allergen extracts from locally lyophilized foods (cow's milk, egg white, egg yolk, wheat, soy, and shrimp), Dermatophagoides pteronyssinus, Dermatophagoides farinae, and American cockroach. MethodsThis study was a prospective, self-controlled study in children with atopic dermatitis. APTs, SPTs, and oral food challenge tests were performed in the cases with written informed consent. ResultsFifty-six children with atopic dermatitis were enrolled. According to the Severity Scoring of Atopic Dermatitis Index, moderate atopic dermatitis was the most common severity (49.1%) followed by mild (20%) and severe atopic dermatitis (13.2%). APT results were positive for food allergens in 49% of participants; SPT results were positive in 54.7%. The sensitivity, specificity, positive predictive value, and negative predictive value of APTs for foods were 40%, 90.2%, 65.2%, and 76.6%, respectively. For SPTs, those values were 40%, 93.9%, 75%, and 77.3%, respectively. APT results for D farinae, D pteronyssinus, and American cockroach were positive in 33.9%, 35.8%, and 21.8% of participants, respectively. SPT results for these allergens were positive in 28.3%, 24.5%, and 9.4% of participants, respectively. No serious complications occurred. ConclusionAPTs with locally prepared lyophilized allergen extracts were safe and had high specificity, median positive predictive value, and low sensitivity for evaluation of suspected food allergy in children with atopic dermatitis. Trial Registrationclinicaltrials.gov Identifier: NCT01164293