A 36 year old unemployed man with a history of depression and heavy alcohol consumption presented to the local accident and emergency department with injuries to both feet. The previous night he had been drinking heavily. He had attempted to return home but did not make it and had spent the entire night sleeping outside in a snow drift.

He was otherwise fit and well with no allergies, and the only drug that he took regularly was citalopram for his depression.

On arrival, he was systemically well with a normal core temperature. Bilateral foot injuries were noted (figure⇓). The more severely affected right foot had a dusky ischaemic appearance, with a clear temperature change at the level of the ankle joint and absent distal pulses. The toes of the left foot were also dusky and cool, with blistering over their dorsal aspect. The distal pulses were weakly palpable in this foot. The patient had no other injuries and all other systems examinations were normal.