Post-transfusion purpura: case report.
Post-transfusion purpura (PTP) is a rare bleeding disorder of platelet alloimmunization that perhaps occurs as an anamnestic reaction. Most commonly, it is observed in PlA1-negative subjects previously sensitized with PlA1 platelet antigen either through PlA1-positive pregnancy or PlA1-positive transfusion. PTP appears with sudden severe thrombocytopenia, purpura, and often life-threatening hemorrhage within 5-10 days of blood transfusion. It is believed to be self-resolving. Yet inactivity risking dangerous bleeding can be disastrous. Treatment with intravenous immunoglobulin, corticosteroids, exchange transfusion, and plasmapheresis has been reported with variable success. No single modality, however, is effective in all cases. Not more than 150 cases of PTP seem to have been reported. We present two such cases. Both were multiparous PlA1-negative women given a blood transfusion for the first time. Corticosteroid therapy failed in both. One responded to intravenous immunoglobulin, while for the other plasmapheresis was the only life-saving modality. One of them subsequently required a blood transfusion for surgical intervention, which could be given uneventfully.