Generally, the causes of fever and high platelet count in babies mainly include the following situations: first of all, due to the symptoms caused by children suffering from Kawasaki disease, after the occurrence of Kawasaki disease will cause fever, high platelet count, accompanied by lymph node enlargement and prune tongue and other symptoms. Some children may even have dilated coronary arteries, so coronary artery ultrasound can be done in time. If the child is diagnosed with Kawasaki disease, medications such as gammaglobulin need to be applied in time for treatment. Secondly, due to the symptoms caused by viral infections, some of the children will have fever and high platelet count after viral infections. The high platelet count at this time is temporary, and the platelet level will naturally return to normal after the viral infections are controlled.