Thrombocytopenia: a complication of Kawasaki disease.

Thrombocytopenia was observed in 10 (2.0%) of 486 children with Kawasaki disease. In nine of the ten, the minimal platelet count of 94,000 +/- 38,000 (SD)/mm3 was seen on day 6.8 +/- 2.2 (SD) of illness and the platelet counts were elevated to the normal level in 1-2 weeks. Thrombocytopenia in the nine appeared to be caused via coagulation-mediated platelet consumption, while the remaining child was diagnosed as having idiopathic thrombocytopenic purpura. One of the two who had severe coagulation-mediated thrombocytopenia of less than 50,000/mm3 developed coronary aneurysms persisting over 1 year.