Rowell N
Br J Dermatol. 1977 Jun;96(6):615-21. doi: 10.1111/j.1365-2133.1977.tb05205.x.
Four patients presenting with painful persistent cyanosis or gangrene of the fingers were found to have anomalies of arterial circulation of the hands and fingers. Investigations for systemic disease were negative. It is postulated that variations in the normal arterial anatomy predispose to digital ischaemia and that trauma, the contraceptive pill or infection may precipitate small thromboses and give rise to clinical ischaemia. Angiography should be undertaken in all patients presenting with persistent ischaemia of the fingers and toes, when the peripheral pulses are present and systemic disease has been excluded.