Subclinical sensitization with diphenylcyclopropenone is sufficient for the treatment of alopecia areata: Retrospective analysis of 159 cases

Abstract

Contact immunotherapy with diphenylcyclopropenone (DPCP) is presently considered the treatment of choice for extensive alopecia areata. However, a major concern with contact immunotherapy is that it causes various adverse effects (AEs) that contribute to discontinuation of treatment. We investigated whether a modified DPCP treatment protocol can promote hair regrowth with fewer AEs. All patients were sensitized with 0.1% DPCP and began treatment with 0.01% DPCP. Thereafter, the DPCP concentration was slowly increased according to the treatment response and AEs. This was a retrospective review of DPCP treatment with modified protocols in 159 patients with alopecia areata. Of the 159 patients, 46 (28.9%) showed a complete response and 59 (37.1%) showed a partial response. No patients had AEs after sensitization. During the treatment, only 3 patients (1.9%) showed severe AEs, and 55 showed moderate AEs; however, all were well controlled with antihistamines alone or antihistamines and medium-potency topical steroids. There was no association between treatment response and AEs. Sample size, subject composition, and the retrospective study design represent potential limitations. A modified DPCP treatment protocol with subclinical sensitization could induce a favorable therapeutic response and result in fewer AEs.