Lesson of the month 2: Non-uraemic calciphylaxis - an unexpected differential diagnosis for a necrotic ulcer

Calciphylaxis is an uncommon cause of skin necrosis seen almost exclusively in patients with end-stage renal disease. We present an unexpected diagnosis of calciphylaxis in a patient with normal renal and parathyroid function. The patient presented with a month-long history of painful bilateral necrotic leg ulcers, resistant to conventional treatment. She developed severe sepsis requiring admission to the intensive care unit, and despite escalation of antibiotic therapy and meticulous wound care management, eventually died. A biopsy confirmed a diagnosis of calciphylaxis. We suspect that warfarin therapy may have contributed to the development of this condition. Through this case we aim to raise awareness of calciphylaxis as a differential diagnosis of non-healing necrotic skin ulcers, especially in patients with known risk factors including established warfarin therapy.