Coumarin-induced skin necrosis. Incidence, mechanisms, management and avoidance.

Coumarin-induced tissue necrosis is a complication of oral anticoagulant therapy characterised by necrosis of the skin and underlying tissue. This occurrence of microvascular thrombosis associated with the administration of an anticoagulant has perplexed the medical and pharmaceutical community since the condition was first recognised in 1943. While the condition is rarely seen, it is of major clinical interest and raises a number of questions concerning pathological mechanisms and patient management. Although some cases occur in patients with hereditary disorders predisposing to thrombosis, the condition remains a mystery in terms of which patients will develop the condition, why the skin and underlying fatty tissues are the target of the microvascular thrombosis, and what the proper approach to a patient with coumarin-induced necrosis should be both in terms of acute management and long term anticoagulant therapy.