Interaction of topical sulfacetamide and topical dapsone with benzoyl peroxide.

A recent study demonstrated evidence of a yellow-orange discoloration of the skin and hair when topical dapsone gel was combined with benzoyl peroxide. This phenomenon had previously been observed by one of us (A.B.F.) when sulfasalazine was combined with benzoyl peroxide. To investigate these interaction phenomena, topical dapsone gel and sulfacetamide sodium lotion were combined with various topical acne treatments, including benzoyl peroxides, clindamycin phosphate, and retinoids. Products containing benzoyl peroxide produced an orange-brown discoloration when mixed with either sulfacetamide or dapsone. Knowledge of the chemical reaction between benzoyl peroxide and sulfacetamide and dapsone will help minimize the occurrence of this interaction on our patients' skin.