PT - JOURNAL ARTICLE AU - Maria Chicco AU - George Filobbos AU - Nicholas Francis AU - Paul Ziprin TI - A mysterious postoperative rash AID - 10.1136/bcr-2017-223999 DP - 2018 May 15 TA - BMJ Case Reports PG - bcr-2017-223999 VI - 2018 4099 - http://casereports.bmj.com/content/2018/bcr-2017-223999.short 4100 - http://casereports.bmj.com/content/2018/bcr-2017-223999.full AB - This case report describes the development of a rash in a patient admitted with large bowel obstruction secondary to carcinoma of the sigmoid colon. The patient underwent a Hartmann’s procedure and right hemicolectomy for a metastatic deposit at the terminal ileum. On postoperative day 3, the patient developed a bullous haemorrhagic rash on the thighs, flanks and abdomen, associated with a sharp drop in platelet count. Suspicion of heparin-induced skin necrosis was raised, and prophylactic enoxaparin was switched to fondaparinux. Skin biopsy results later confirmed the diagnosis. Clinical suspicion of heparin-induced skin necrosis is essential and should prompt a switch between prophylactic agents, in order to prevent potentiation of this life-threatening side effect.