A migrant worker from Central America with diffuse lepromatous leprosy presents with large, star-shaped necrotic ulcers on the lower limbs without preceding nodules. Biopsy shows necrotizing vasculitis with thrombosis of dermal vessels and heavy bacillary load. Which reaction pattern is this?
- A Lucio phenomenon ✓
- B Erythema nodosum leprosum
- C Type 1 reversal reaction
- D Histoid leprosy
Correct answer: A. Lucio phenomenon
Explanation
The Lucio phenomenon occurs in diffuse lepromatous leprosy (Lucio-Latapi type), seen mainly in Mexico and Central America. It presents as geometric, stellate necrotic ulcers caused by necrotizing vasculitis and thrombosis of small dermal vessels, without the tender erythematous nodules of erythema nodosum leprosum. It does not respond well to thalidomide, unlike ENL, and management relies on clofazimine and systemic corticosteroids.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.