Kawasaki disease is an acute systemic vasculitis of unknown cause first described in Japan in 1967. It affects children younger than 10 years, predominantly those younger than 3 years. Children of Asian ancestry are more commonly affected than white children. The diagnosis is made when 4 of the following 5 signs or symptoms are present with fever for at least 5 days: polymorphous rash; conjunctival injection; oral mucosal changes; cervical lymphadenitis; and erythema, swelling, or desquamation of the hands and feet. Various symptoms may be seen also, among them pronounced irritability, arthralgia, and abdominal pain. No diagnostic test exists, and clinicians must carefully exclude diseases that mimic Kawasaki disease. In addition to the above clinical findings, Kawasaki disease causes aneurysm formation in medium-sized arteries, particularly the coronary arteries. Found in about a fourth of patients, these lesions may persist, scar with stenosis, or resolve angiographically. The treatment consists of administering high-dose aspiring and intravenous immune globulin, with the goal of relieving acute illness and minimizing sequelae. Although most respond rapidly, almost 10% of children do not improve clinically with treatment. Complications of Kawasaki disease include myocardial infarction, which may occur during acute illness or later, as a result of coronary abnormalities.