Although dapsone (Avlosulfon) is most often used as an antimicrobial agent, it has important antiinflammatory properties in many noninfectious skin diseases. The mechanism of action of dapsone in skin disease is not clear. Most of the cutaneous diseases for which it is effective manifest inflammation and are characterized by an infiltration of neutrophils; the drug’s antiinflam-matory effect may arise from its inhibition of intracellu-lar neutrophil reactions mediated by myeloperoxidase and hydrogen peroxide or from its scavenging of reac-tive oxygen species, which inhibits inflammation.
Dapsone is approved for the treatment of an au-toimmune blistering skin disease, dermatitis herpeti-formis. This intensely pruritic eruption is characterized histologically by a dense dermal infiltration of neu-trophils and subepidermal blisters. Other skin diseases in which dapsone is helpful are linear immunoglobulin A (IgA) dermatosis, subcorneal pustular dermatosis, leukocytoclastic vasculitis, and a variety of rarer erup-tions in which neutrophils predominate, including some forms of cutaneous lupus erythematosus.