A 66-year-old woman had a 41⁄2 year history of urticarial vasculitis confirmed by skin biopsy.1 She was on long-term prednisolone 10mg/day; she had recently received a short course of colchicine. She presented to casualty with acute swelling of the left calf, which was tender, warm and firm but not, at this stage, discoloured. A deep venous thrombosis was suspected. No investigations were done at this stage (d-dimers were not available in the hospital). She was treated with low molecular weight heparin and was asked to return the next day for Doppler studies. However, her general condition proceeded to worsen. Swellings occurred in her other leg and in both upper limbs. She began to feel light-headed and she fainted. On return to casualty, it was observed that all of the limbs now showed both swelling and frank bruising which was widespread and appeared to be of deep origin. Figure 1 shows her condition a day after admission. She denied bleeding from the skin or gastrointestinal tract. Her pulse was 120min71 and regular; the blood pressure was 118/66 mmHg lying, 92/44 standing. Routine blood tests showed Hb, 5.0 g/dL; white blood count 116109/L; MCV, 86 fl; platelets, 2006109/L; ESR, 65 mm; the urea and electrolytes and liver tests were all normal. At this point, the diagnosis was not clear. A simple DVT it was not. Although there was a spontaneous bruising problem, the platelet count was normal, and in any case this was not the kind of superficial skin bruising seen in thrombocytopenia. Tests of coagulation were performed. The prothrombin and thrombin times were normal but the