Leishmaniasis Masquerading as Lepromatous Leprosy: A Rare Dermatological Diagnostic Pitfall.

Dermal leishmaniasis, particularly postkala-azar dermal leishmaniasis (PKDL), is an uncommon entity that may closely mimic lepromatous leprosy in endemic regions. Both conditions present with chronic, symmetric nodular or plaque-like lesions, leading to frequent diagnostic confusion, especially when peripheral nerve thickening is absent. We report a 71-year-old male with a 15-year history of diffuse erythematous nodules and scaly plaques over the palms and dorsum of the feet, repeatedly managed as lepromatous leprosy without clinical improvement. The absence of peripheral nerve thickening and a negative slit-skin smear prompted further evaluation. Skin biopsy demonstrated macrophages packed with Leishmania donovani (LD) bodies, and polymerase chain reaction (PCR) targeting the ITS-1 gene confirmed LD. The patient was initiated on miltefosine 50 mg twice daily for 12 weeks (standard regimen). At 4-week follow-up, lesions showed approximately 30% flattening, and at 12 weeks, more than 60% regression was noted, without adverse effects. This rare case of a 71-year-old male with >15 years of misdiagnosis highlights that chronic diffuse nodular dermatosis without nerve involvement should prompt consideration of PKDL even in the absence of documented prior visceral leishmaniasis. Accurate diagnosis using histopathology and PCR prevents prolonged inappropriate therapy and reduces the risk of community transmission.