Benzoyl peroxide: lack of sensitization.

A prospective study of 445 patients using benzoyl peroxide, observed regularly over a 12-month period, uncovered only a very low incidence of moderate or severe local reaction. There was, however, a significant level of mild primary irritant dermatitis which settled with continued use. In only 6 patients was there severe local reaction; one patient was lost to follow-up but in the 5 patients patch tested, only one had a contact allergic dermatitis. The study indicates the overall cutaneous safety of benzoyl peroxide.