Systematic Review and Quality Analysis of Studies on the Efficacy of Topical Diphenylcyclopropenone Treatment for Alopecia Areata

The document analyzed 26 studies on the use of topical diphenylcyclopropenone (DPCP) for treating alopecia areata (AA), with an average response rate of 53.75% among all participants. The studies included a range of patient numbers, with 5 studies having ≤20 patients, 7 studies with 21-40 patients, and 14 studies with >40 patients. For more severe cases like alopecia totalis (AT) and alopecia universalis (AU), the response rate was slightly lower at 47.65%. Adverse events were common, with eczematous reactions and lymphadenopathy being the most reported. The review pointed out several limitations such as language bias, absence of control groups, and inconsistent scoring systems. Despite these limitations, the authors found evidence of DPCP's efficacy for AA but called for more rigorous randomized controlled trials to confirm these findings.