A 19-year-old girl presents with recurrent tender dusky-red nodules on the back of both calves that ulcerate in winter and heal with depressed scars. She has a strongly positive Mantoux test. Biopsy shows lobular panniculitis with fat necrosis and caseation. What is the diagnosis?
- A Erythema nodosum
- B Erythema induratum of Bazin ✓
- C Nodular vasculitis unrelated to tuberculosis
- D Polyarteritis nodosa, cutaneous type
Correct answer: B. Erythema induratum of Bazin
Explanation
Erythema induratum of Bazin is a tuberculid presenting as recurrent nodules on the posterior calves of young women that ulcerate and heal with scarring. Histology shows lobular panniculitis with fat necrosis and often caseous necrosis, with a strongly positive tuberculin test. It is distinguished from erythema nodosum by location, ulceration, scarring, and the panniculitis pattern; erythema nodosum is septal, affects the shins, and resolves without scarring. Many cases respond to antitubercular therapy.
Reference: Rook's Textbook of Dermatology, 9th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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