Diphencyprone in the treatment of long-standing alopecia areata.

Thirty-six patients with alopecia areata of 1-54 years duration entered a study of treatment with the contact allergen diphencyprone for 8 months. Following sensitization the diphencyprone was applied to one half of the scalp at weekly intervals, the other half acting as a control. Once hair growth was established on one side, the other side was treated. Seven patients did not continue treatment and one patient showed spontaneous regrowth. Of the remaining 28 patients who persisted with treatments, fourteen (50%) regrew hair on the treated side; eight (29%) had a cosmetically acceptable result with the regrowth of terminal hair over the whole scalp. No statistically significant differences were found in age or duration of alopecia between those who regrew and those who did not. We have found diphencyprone to be an effective stimulator of hair growth in patients with severe and long-standing alopecia areata.