We investigated 17 patients with Henoch-Schönlein purpura (HSP) and describe as yet unreported abnormal results of blood coagulation tests. In parallel to the activity of the disease, D-dimer concentrations in plasma were found to be significantly increased in 15 of the 17 patients; almost 50% of all patients showed values higher than 10 times the upper limit of the normal range. In 11 patients, plasma concentrations of thrombin-antithrombin complex (TAT) and prothrombin fragments 1 and 2 (F1+2) were examined; six of them showed abnormal results. The pathologic values were correlated to the activity of the disease, but abnormalities were also found in milder cases of HSP. These findings probably reflect local reactions within inflamed blood vessels rather than a systemic activation of coagulation and hyperfibrinolysis. Clinicians should be aware of these laboratory findings in order not to confuse common cases of HSP with purpura necroticans, a very severe type of vasculitis in which signs of disseminated intravascular coagulation (DIC) have been reported. Our findings suggest that an activation of coagulation including hyperfibrinolysis secondary to the endothelial damage is a typical feature of the common types of HSP.
