Platelet and coagulation studies in Ehlers-Danlos syndrome.

Fifty-one patients with Ehlers-Danlos syndrome were investigated for abnormalities of platelets and coagulation. Thirty-eight were examined prospectively and 13 retrospectively. A bleeding history was taken from all patients; only four (8%) gave no history of a bruising or bleeding tendency. Nine patients (18%) had significant haemostatic abnormalities of whom four (8%) had a platelet release defect, three (6%) had a factor XI deficiency and two (4%) had a factor XIII deficiency. Additionally 16 patients (31%) had mild abnormalities of uncertain significance of whom four (8%) had prolonged bleeding times (three in association with platelet aggregation abnormalities), 13 (26%) had platelet aggregation abnormalities and two had a positive Hess test. Twenty-four patients (47%) had normal tests for haemostasis of whom 20 (39%) had a bleeding diathesis and four (8%) had no such tendency. Results were analysed according to the type of Ehlers-Danlos syndrome, but there was no pattern to the abnormalities. The high frequency of a bleeding tendency in Ehlers-Danlos patients with normal tests for haemostasis (83%) supports the conventional explanation for this clinical feature, that defects in the structural integrity of skin and blood vessels lead to easy bruising.