Dinitrochlorobenzene treatment of alopecia areata.

Forty-two patients with alopecia areata were treated with local applications of dinitrochlorobenzene (DNCB); We used DNCB in two forms, an acetone solution applied weekly or a cream used every day, employing a wide range of DNCB concentrations. The concentration used was varied at the time of each application to produce a contact dermatitis. Seven patients experienced complete and lasting hair regrowth, 17 had poor results, and in 18 patients the treatment was a failure. Acquired tolerance to DNCB was observed in six patients; in five it was abolished by the administration of cimetidine. Certain factors such as the delay in appearance and the intensity of the sensitization reaction influence the hair regrowth. Poor prognostic criteria for treatment effect included a history of previous systemic corticosteroid therapy, atopy, and the presence of alopecia areata in close relatives.