Kawasaki syndrome (KS) is an acute febrile illness of unknown etiology that primarily affects children younger than 5 years of age. KS was first described in Japan by Tomisaku Kawasaki in 1967, and the first cases outside of Japan were reported in Hawaii in 1976. KS is characterized by fever, rash, swelling of the hands and feet, irritation and redness of the whites of the eyes, swollen lymph glands in the neck, and irritation and inflammation of the mouth, lips, and throat. Serious complications of KS include coronary artery dilatations and aneurysms, and KS is a leading cause of acquired heart disease in the United States.