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Bleeding tendency and disease activity in Henoch–Schönlein purpura: Comment

Dear Editor, We read with interest the article “A case of Henoch– Schönlein purpura temporarily improved by hemodialysis” by Tsuboi et al. They showed a temporary reduction of purpura by hemodialysis in their patient and the Rumpel–Leede test also improved concurrently. However, they could not explain the possible mechanisms. Bleeding tendency in Henoch– Schönlein purpura (HSP) is determined by an abnormal platelet aggregation, endothelial injury, and an altered coagulation–fibrinolysis system. Elevated plasma levels of von Willebrand factor are a wellrecognized feature of vasculitis and have been taken as an indication of endothelial cell damage. Also, a reduced factor XIII activity is closely related to bleeding tendency during the acute phase of HSP, although HSP is classically described as a systemic vasculitis without known platelet or clotting abnormality. At present, persistent purpura, severe abdominal symptoms, and decreased factor XIII activity have been reported to be associated with the renal involvement of HSP. These parameters were not measured in their evaluations, but might have influenced the development or disappearance of purpura before and after hemodialysis or peritoneal dialysis. Therefore, it would be helpful to measure von Willebrand factor or factor XIII activity concurrently as well as symptoms when we assess a disease activity in patients with HSP, and further studies are necessary to elucidate the impact of hemodialysis or peritoneal dialysis on these parameters.