DAPSONE INDUCED METHAEMOGLOBINEMIA IN A CASE OF BORDERLINE TUBERCULOID LEPROSY

Dapsone, a sulfone antibiotic, is widely used in the treatment of leprosy. One of its uncommon but potentially serious adverse effects is acquired methemoglobinemia. We report a case of a 15-year-old female diagnosed with multibacillary borderline tuberculoid leprosy who developed symptomatic methemoglobinemia while on multidrug therapy including dapsone. She presented with breathlessness, chest pain, and headache, with oxygen saturation of 88% on room air. Arterial blood gas revealed methaemoglobin level of 16.9%. The patient responded well to intravenous methylene blue therapy with normalization of methaemoglobin levels. Dapsone was identified as the most likely precipitating factor. This case highlights the importance of clinical suspicion, timely diagnosis, and prompt treatment of dapsone-induced methemoglobinemia to prevent morbidity.