A woman with spreading erythema after caesarean section

A 26 year old woman presented to the emergency department six days after having a caesarean section with an area of spreading erythema extending from her wound site over the infra-umbilical abdomen (fig 1). She had a body mass index of 30 and gestational diabetes, and during labour had experienced premature rupture of membranes. She reported that the area of erythema had doubled in size over the preceding 12 hours and an area of dark bruising had appeared over the last four hours. The wound had become increasingly painful, despite regular analgesia, with a pain score of …