The Efficacy, Safety, and Recurrence Rate of Diphenylcyclopropenone Topical Immunotherapy for Alopecia Areata: A Systematic Review and Meta-Analysis

This systemic review and meta-analysis of 40 studies involving 3,002 patients found that diphenylcyclopropenone topical immunotherapy is effective for treating alopecia areata, with an overall hair regrowth rate of 69% and complete regrowth in 23% of cases. Patients with alopecia totalis or universalis had a lower regrowth rate (42%) compared to those with other types of alopecia areata (75%). Common side effects included mild (36%) and severe (31%) contact dermatitis, regional lymphadenopathy (22%), hyperpigmentation (22%), and hypopigmentation (7%). The recurrence rate was 37%. Despite these side effects, the treatment is considered effective and the side effects acceptable.