[Orthostatic purpura: report of two cases].

Two patients with orthostatic purpura were reported. Case 1: A 47-year-old man was admitted to our institution because of multiple purpuric eruptions over the legs after the long periods of sitting or standing. Bleeding time was 4.0 min. Platelet aggregation induced by ADP was disaggregated and no aggregation was observed when induced by collagen and epinephrine. He was diagnosed as having release abnormality of the platelets caused by glutathione administered for treatment of liver damage for several years. Purpura, however, appeared even though platelet function became normal after discontinuing glutathione. Purpura proved to be induced by the long periods of sitting or standing. Case 2: A 37-year-old woman was admitted to our hospital because of purpuric eruptions over the legs for three years. Bleeding time was 2.0 min. Platelet aggregation induced by ADP, epinephrine, collagen and ristocetin was normal. Purpura was caused by long periods of standing without movement. Wearing elastic pantyhose showed reduced appearance of the purpura. Biopsy specimens from both patients revealed no abnormal findings. Both patients had no abnormal results in coagulation studies. Purpura seemed to be caused by the increased capillary pressure after the prolonged periods of standing. No case report concerning orthostatic purpura or mechanical purpura has been published.