You are correct. Histopathology confirmed the dx of calciphylaxis, a rare and often fatal disease associated with progressive cutaneous ulceration. It’s characterized by skin arteriole calcification and thrombosis with subcutaneous inflammation. Multiple factors contribute, such as disorders of calcium and PO4 metabolism and the probable deficiency of vascular calcification inhibitors such as fetuin-A. Although calciphylaxis predominantly occurs in patients with end-stage renal disease, it’s been reported in those without renal failure who have hyperphosphatemia, in those with RA (a probable comorbidity), and with prednisolone consumption (a possible risk factor, but the potential confounding by indication or other drugs should be considered).

This patient was treated by control of PO4 and calcium levels, with IV sodium thiosulfate 3x/wk. The skin ulcers and pain resolved gradually.

Archives of Disease in Childhood 2022;107:1137