Navigating the mysteries of erythema nodosum leprosum masquerading as Lucio’s phenomenon: a case report

In leprosy patients, circulating immune complexes, vasculitis, or T-cell-mediated reactions cause inflammatory responses, leading to purpuric and ulcerative skin lesions, including the vasculo-necrotic Lucio phenomenon (LP) simulating necrotic erythema nodosum leprosum (ENL). In this study, we report a 73-year-old man presenting with purpuric lesions on his upper and lower extremities, transforming to bullous, ulcerative lesions, and eschar. Slit skin smear showed a bacteriological index of +2.5 and a morphological index of 14.2%. The patient was diagnosed with multibacillary leprosy with LP. Skin biopsies were consistently indicative of lepromatous leprosy (LL) with ENL reaction. The patient was started on antileprosy treatment with daily administration of Clarithromycin, Ofloxacin, and Clofazimine. Methylprednisolone was started after ten days of antileprosy treatment due to erythematous nodular lesions and fever. The patient improved significantly after steroid medication. This case emphasizes the importance in recognizing different manifestations of necrotic ENL to appropriately diagnose and treat patients.