For the KD patients with fever persisted or relapsed 24 hours after the ending of IVIG infusion, they will be randomized into two group: IVIG group (I) and IVIG + prednisolone group (P). The KD patients in the P group will have in addition to IVIG, oral prednisolone 2mg/kg/day for at least 5 days. The difference in the response rate and percentage of coronary involvement will be compared between I and P groups.