It occurs in patients with retroperitoneal bleeding, usually due to acute haemorrhagic pancreatitis.
Named after London surgeon John Adrian Fox after he reported 2 fatal cases of non-traumatic ecchymosis in the upper outer aspect of the thigh as a diagnostic sign of retroperitoneal haemorrhage.
[1] Often incorrectly eponymously attributed to the American dermatologist George Henry Fox (1846–1937) despite JA Fox's paper being published in 1966.
Fox's sign at Whonamedit?
This medical sign article is a stub.