Three doses of dapsone causing methemoglobinemia in leprosy: A report of two cases

Dear Editor, Dapsone (4,40-diaminodiphenylsulfone)—the oldest known antibiotic with anti-inflammatory and immunomodulatory activity, is widely prescribed for various dermatological conditions as Dermatitis herpetiformis, neutrophilic dermatoses, etc. and forms a backbone of treatment in Hansen's disease. There are various well-known idiosyncratic as well as pharmacologically expected side effects of the drug including methemoglobinemia which is a rare, dose-dependent adverse effect and has usually been described in the literature post long-term drug usage over weeks to months or with high daily doses (2 mg/kg). We hereby report two rare cases of Hansen's disease who developed dapsone-induced methemoglobinemia within only 3 days of therapy. A 16-year-old boy presented to the emergency department with sudden onset bluish discoloration of fingers, tongue and lips (Figure 1 A and B) along with mild headache of one-day duration. There was no history of dyspnea, prolonged cold or heavy metal exposure, dysphagia,