Topical Treatment of Alopecia Areata

The study compared the effectiveness of dinitrochlorobenzene (DNCB), a contact allergen, and croton oil, a primary irritant, in treating alopecia areata in 22 patients. Results showed that 63% of patients without spontaneous hair regrowth experienced hair regrowth after DNCB application, while none responded to croton oil. Patients initially treated with croton oil regrew hair when later treated with DNCB, indicating that a contact allergen was necessary for therapeutic success. Despite concerns about DNCB's mutagenicity, patient acceptance of the induced contact dermatitis was excellent, prompting the search for other contact allergens for topical immunotherapy.