Livedoid Vasculopathy — SCE Dermatology MCQ

Correct answer: D — Livedoid vasculopathy

The correct answer is D, livedoid vasculopathy. This condition produces painful, punched-out stellate ulcers on the lower leg (classically medial ankle or gaiter area) that heal with atrophie blanche, ivory-white scarring with surrounding telangiectasia, plus livedo racemosa from impaired dermal perfusion. Livedoid vasculopathy is a thrombo-occlusive process, not a true vasculitis, so biopsy shows fibrinoid thrombosis and hyalinisation of dermal vessel walls with minimal or no inflammatory infiltrate, distinguishing it from vasculitic ulcers. This combination of clinical morphology (stellate ulcer, atrophie blanche, livedo) and histology (thrombosis without vasculitis) is the recognised diagnostic pattern for this disorder, and management centres on antiplatelet or anticoagulant therapy rather than immunosuppression. Why the other options are wrong: A. Calciphylaxis: causes retiform purpura and necrotic ulcers typically in patients with end-stage renal disease and vascular calcification, with biopsy showing calcification of small vessels rather than fibrinoid thrombosis alone, and it lacks the classic atrophie blanche scarring. B. Polyarteritis nodosa: is a true necrotising vasculitis of medium-sized vessels, producing tender subcutaneous nodules, livedo and ulcers, but biopsy shows transmural inflammatory vasculitis, which the stem explicitly excludes. E. Venous leg ulcer: occurs over the gaiter area with associated venous eczema, haemosiderin staining and lipodermatosclerosis, but ulcers are typically shallow and irregular rather than punched-out stellate lesions, and histology shows venous stasis changes, not dermal vessel thrombosis. C. Pyoderma gangrenosum: presents with a rapidly enlarging ulcer with a violaceous, undermined border and purulent base, often with pathergy; histology shows neutrophilic infiltration, not fibrinoid vascular thrombosis. Key point: Punched-out leg ulcers with atrophie blanche and biopsy showing fibrinoid vessel thrombosis without vasculitic inflammation is diagnostic of livedoid vasculopathy, a thrombotic (not inflammatory) vasculopathy treated with antiplatelet or anticoagulant therapy.

Reference: DermNet NZ, Atrophie Blanche (2023), https://dermnetnz.org/topics/atrophie-blanche