The detection of clinically relevant contact allergens with a standard screening tray of 28 allergens

Abstract

A standard method for diagnosing allergic contact dermatitis in the United States is the thin-layer rapid use epicutaneous (TRUE) test (TRUE Test™), which consists of three panels containing 20 individual allergens and eight allergen mixes. Previous studies had raised concern regarding the adequacy of the initial two-panel TRUE Test™ system (16 individual allergens and seven allergen mixes) in fully assessing patients with possible allergic contact dermatitis. We sought to investigate the effectiveness of the current three-panel TRUE Test™ as the sole diagnostic tool for detecting allergic contact dermatitis. This study was a retrospective analysis of 2088 patients who underwent patch testing between 1995 and 2010. Study groups were analysed to determine whether positive reactions were to allergens and/or mixes present in the TRUE Test™ panels. Of the 2088 patch-tested patients, 1385 had at least one positive reaction. Among these 1385 patients, 27.6% were fully evaluated by use of only the TRUE Test™ series, 49.9% were partially evaluated, and 22.5% did not have any of their allergens detected. On assessment for clinical relevance, similar percentages were observed. In our study, the current TRUE Test™ series of 28 allergens would have completely identified allergens in only 27.6% of patients. Broadening the standard panel to include common allergens causing >50% of allergic contact dermatitis cases in a given geographical location and aim testing allergens on the basis of the patient's history will increase the test's sensitivity.