A 17 year old presented with a painful, erythematous lesion to the dorsum of his right foot following minor trauma. The lesion was cold, 5 cm in diameter with a well-defined edge surrounding scattered petechiae (figure 1). He was unable to move his foot or weight bear due to pain. C-reactive protein and plain x-rays were normal.
The patient has chronic kidney disease (CKD) stage 5 due to IgA nephropathy and had received haemodialysis for 16 months. Serum calcium, phosphate and parathyroid hormone (PTH) were raised at 2.56 mmol/l, 3.32 mmol/l and 19.5 pmol/l. Compliance with diet and medication was inconsistent.
A clinical diagnosis of calciphylaxis was made. The patient was treated with daily dialysis sessions, cessation of both vitamin D analogues and calcium-based phosphate binders and instigation of Cinacalcet. He required opiate analgesia. The lesion improved with control of his calcium-phosphate product.