Borderline tuberculoid leprosy misdiagnosed as erysipelas: A case report and literature review.

Leprosy is a disabling infectious disease caused by Mycobacterium leprae. This article reports the case of a 51-year-old woman who presented with a 20-day history of erythema, swelling, numbness, and pain in her right upper limb, which showed no improvement following initial treatment for erysipelas. Subsequently, based on a positive repeat skin smear for Mycobacterium leprae, the diagnosis was revised to leprosy, with definitive confirmation provided by histopathological examination and a positive acid-fast stain. This case highlights the critical diagnostic pitfall in paucibacillary leprosy, where an initially negative smear can delay diagnosis, underscoring the need for repeat testing and histopathological correlation when clinical suspicion persists.