A Mexican immigrant with long-standing diffuse infiltration of the entire body skin, loss of eyebrows, and no discrete nodules suddenly develops multiple dusky, painful, ulceronecrotic plaques over his arms and trunk. Biopsy shows necrotising vasculitis with thrombosis of dermal vessels. Which statement about this entity is correct?
- A It represents erythema nodosum leprosum in Lucio latapi leprosy and may not respond to thalidomide ✓
- B It is a type 1 reaction and responds best to thalidomide
- C It indicates upgrading from borderline to tuberculoid spectrum
- D It is caused by Mycobacterium ulcerans and treated with rifampicin and clarithromycin
Correct answer: A. It represents erythema nodosum leprosum in Lucio latapi leprosy and may not respond to thalidomide
Explanation
This is the Lucio phenomenon (erythema necroticans) occurring in diffuse lepromatous leprosy of Lucio and Latapi, described originally in Mexico. Histologically it shows necrotising vasculitis and thrombosis rather than the neutrophilic microabscesses of typical ENL. Clinically it often responds poorly or incompletely to thalidomide, unlike classic ENL, and systemic corticosteroids are required. It is a type 2 reaction, not a reversal (type 1) reaction, and M. ulcerans causes Buruli ulcer, an entirely separate condition.
Reference: Harrison Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.