Update on the use of dapsone in dermatology.

Dapsone (4,4'-diaminodiphenylsulfone) is the only remaining sulfone used in anthropoid therapeutics and is commercially available as an oral formulation, an inhaled preparation, and a 5% or 7.5% cream. Dapsone has antimicrobial effects stemming from its sulfonamide-like ability to inhibit the synthesis of dihydrofolic acid. It also has anti-inflammatory properties such as inhibiting the production of reactive oxygen species, reducing the effect of eosinophil peroxidase on mast cells and down-regulating neutrophil-mediated inflammatory responses. This allows for its use in the treatment of a wide variety of inflammatory and infectious skin conditions. Currently in dermatology, the US Food and Drug Administration (FDA)-approved indications for dapsone are leprosy, dermatitis herpetiformis, and acne vulgaris. However, it proved itself as an adjunctive therapeutic agent to many other skin disorders. In this review, we discuss existing evidence on the mechanisms of action of dapsone, its FDA-approved indications, off-label uses, and side effects.