Behçet's disease (BD), first described in 1973, is characterised by recurrent oral and genital ulcers as well as eye inflammation. Other features of this chronic multisystem inflammatory disease include neurological, cardiovascular, pulmonary, gastrointestinal, musculoskeletal, and dermatological involvement.1

Venous or arterial thrombosis occurs in 25% (10–37%) of patients.2 Venous thrombosis is more common than arterial thrombosis (88% v 12%).3 Deep and superficial venous thrombosis of the legs predominates.4-7

Arteritis is treated with a combination of corticosteroids and cytotoxic agents. Anticoagulants and antiplatelet agents are used for deep venous thrombosis, though there has never been a properly controlled study to justify this treatment in BD.8

The thrombin-antithrombin complex (TAT) is a marker of intravascular thrombin formation. Prothrombin fragments 1+2 (PF1.2) are peptide fragments generated when prothrombin is activated to thrombin. TAT and PF1.2 are both biological markers of thrombin generation and thus correlate with thrombotic risk.9 ,10

Several studies have shown increased levels of PF1.2 and TAT in patients with BD.11 ,12 These alterations probably reflect the activation of the coagulation cascade in these patients and are not the cause of the thrombosis.

Vasculitis, the main pathological process in BD, can partially explain the thrombotic phenomena.13 Why such thrombosis is not so common in other vasculitides, and why it occurs in only about 25% of patients with BD, is still unclear.

As knowledge about the cause of venous and arterial thrombosis is growing, it is now clear, that thrombosis may result from a combination of hereditary and acquired abnormalities. It is speculated that a combination of abnormalities of procoagulants, anticoagulants, and fibrinolytic factors, together with the vasculitis and the endothelial injury, accounts for the clinical thrombosis in this subgroup of patients with BD.

The present review is a critical summary of the …