ANALYSIS OF PATCH TEST RESULTS FOR INDIVIDUAL INGREDIENTS IN PATIENTS WITH ALLERGIC CONTACT DERMATITIS CAUSED BY 10% EFINACONAZOLE NAIL SOLUTION

Abstract

Ten percent efinaconazole nail solution (EFCZ solution) is a new topical triazole antifungal drug, and we sometimes encounter patients with allergic contact dermatitis (ACD) caused by EFCZ solution in our outpatient clinic. However, no previous reports have summarized the patch test (PT) results obtained for individual ingredients in several patients with EFCZ solution-induced ACD. This study aimed to 1) confirm the causative agent of EFCZ solution-induced ACD based on PT of individual ingredients and 2) analyze the optimal concentration and vehicle for such PT on the basis of previous studies. We clinically diagnosed eight patients with EFCZ solution-induced ACD from Sep. 2014 to Aug. 2021, and performed 48-hour closed PT using EFCZ solution and its ingredients. Readings were done on days (D) 2, 3, and 7 according to the International Contact Dermatitis Research Group criteria. Six of the 8 patients underwent PT with EFCZ solution, and all showed + to +++ reactions on D3. The results for the main component, EFCZ, were + to +++ on D3 in all patients. Two patients were patch tested with both 10% EFCZ in ethanol and 10% EFCZ in petrolatum, which produced similar reactions. One patient had an allergic reaction to ethanol. The causative agent of EFCZ solution-induced ACD was EFCZ in all patients. For PT, we recommend EFCZ solution as is, its 10-fold dilution and 1% and 0.1% EFCZ in petrolatum.