Association between hyperflexibility of the thumb and an unexplained bleeding tendency: is it a rule of thumb?

A bleeding tendency manifested by petechiae and ecchymoses is one of the most common causes for referral of patients to haematology clinics. Vessel wall pathology is not usually considered to be a cause for deranged haemostasis, although coexistence of increased capillary fragility and joint hypermobility have been reported. We determined the frequency of thumb hyperextensibility and scored the findings in a series of 44 patients referred because of ecchymoses and petechiae, as well as 261 control children and their mothers. All 44 patients had normal coagulation studies. Thumb flexibility score was +4 in 30 patients, +3 in eight patients, +2 in five patients and +1 in one of the index patients. In the control group, only one of 261 had a +4, and three had a +3 score, and two of 260 mothers had a +4 score. Ecchymoses were not observed in any of these subjects, nor in the +1 patients. Based on clinical presentation and normal coagulation studies, we suggest that our patients had an underlying subtype of Ehlers-Danlos syndrome. In view of the dramatically high occurrence of thumb hyperextensibility in patients with unexplained mild bleeding tendency, costly haemostatic and coagulation studies on such patients may not be necessary.