Dapsone induced methemoglobinemia in leprosy: A close mimic of 'happy hypoxia' in the COVID-19 pandemic.

Dermatological examination revealed a solitary, well defined, hypotrichic, hypohidrotic, annular plaque, 7 cm in diameter over the dorsum of the left foot which was hypoaesthetic to pain, touch and temperature. No satellite lesions or nerve to patch was present. Left posterior tibial nerve and superficial peroneal nerve were thickened and non tender.