Dermatitis herpetiformis: titrate individually, starting adults at 50 mg daily, with correspondingly smaller doses in children. If full control is not obtained at 50 to 300 mg/day, higher doses may be tried. Reduce promptly to the minimum maintenance dose. Pruritus improves promptly in responders, then skin lesions clear. There is no effect on the gastrointestinal component. Acetylation rate and drugs affecting acetylation may alter dose requirements. A strict gluten-free diet may reduce/eliminate dapsone need: source average reduction time 8 months (range 4 months to 2.5 years) and elimination time 29 months (6 months to 9 years).
Leprosy: the source WHO/USPHS advice is combination with at least one other anti-leprosy drug to reduce secondary resistance. In multidrug programs, use 100 mg/day without interruption (smaller corresponding pediatric doses) for susceptible new/recrudescent disease or an incomplete 2-year monotherapy course. It lists USPHS Carville, LA, telephone 1-800-642-2477, and advises checking labeling for other drugs.
Bacteriologically negative tuberculoid/indeterminate disease: dapsone 100 mg/day plus rifampin 600 mg/day for 6 months, or supervised WHO rifampin 600 mg monthly. Continue dapsone until clinical activity is controlled, usually 6 further months, then 3 further years for tuberculoid/indeterminate and 5 years for borderline tuberculoid disease.
Lepromatous/borderline lepromatous disease: dapsone 100 mg/day plus rifampin 600 mg/day for 2 years, or supervised WHO rifampin 600 mg monthly. An optional third drug is clofazimine 50 to 100 mg/day or ethionamide 250 to 500 mg/day. Continue dapsone 100 mg/day for 3 to 10 years until all clinical activity is controlled and skin scrapings/biopsies are negative for 1 year, then an additional 10 years for borderline disease and lifelong for lepromatous disease.
Suspect secondary resistance after clinical/bacteriologic relapse with solid-staining bacilli in new lesions. Failure to respond to regular supervised therapy over 3 to 6 months, or assured adherence in the preceding 3 to 6 months, is described as clinical confirmation. The historical source recommends mouse-footpad sensitivity testing arranged with USPHS Carville; proven resistance requires other drugs.