A case of acute thrombocytopenic purpura following rubella vaccination is reported. A 3-year-old boy developed purpura on the 22nd days after rubella vaccination. His platelet count was 34×103/μl. Platelet-associated IgG was elevated, but the amount of megakaryocytes in bone marrow aspirates was within the normal range, suggesting immune mechanism-associated thrombocytopenia. He recovered spontaneously within one month. Thrombocytopenic purpura is a well-documented complication of natural rubella infection. Attention should be paid rubella vaccination-associated thrombocytopenia, though it seems to be less frequent than after natural infections.
