Painful skin lesion in a patient on haemodialysis: a diagnosis not to miss.

An 81-year-old man was admitted under the care of a plastic surgery team with a 10-day history of a painful left lower leg skin lesion after a punch biopsy of a naevus. His background history includes end-stage kidney disease secondary to hypertensive nephropathy, on intermittent haemodialysis via fistula. Other significant background history includes stroke, hypertension and ischaemic heart disease with coronary artery stents. There was no history of warfarin use. He was initially treated with a 5-day course of oral antibiotics with no improvement. He was referred to the hospital where he was admitted under the plastic surgery team who had completed the punch biopsy for intravenous antibiotics for presumed cellulitis. During his admission, the nephrology service were consulted to prescribe routine inpatient haemodialysis. Further history taking and wound review identified a 10-day history of an extremely painful skin lesion with an eschar and surrounding dusky, purpuric skin. Given the disproportionate pain and black eschar which are not in keeping with cellulitis, a diagnosis of calciphylaxis was made. He was commenced sodium thiosulfate on haemodialysis.