Kawasaki disease (KD), also known as Kawasaki syndrome, is an acute febrile illness of unknown etiology that primarily affects children younger than 5 years of age. The disease was first described in Japan by Tomisaku Kawasaki in 1967, and the first cases outside of Japan were reported in Hawaii in 1976.
Clinical signs include 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.
KD is a leading cause of acquired heart disease in the United States. Serious complications include coronary artery dilatations and aneurysms. The standard treatment, intravenous immunoglobulin and aspirin, substantially decreases the development of these coronary artery abnormalities.
KD occurs worldwide, with the highest incidence in Japan, and it most often affects boys and younger children. KD may have a winter-spring seasonality, and community-wide outbreaks have been reported occasionally.
CDC has maintained a KD surveillance system since 1976 and uses several data sources to track and better understand KD in the United States:
- CDC analyzes large hospital discharge databases to describe the incidence and epidemiology of KD in the United States. Because most children with KD are hospitalized, the hospitalization rate is a good estimate of KD incidence.
- CDC uses a passive KD surveillance system based on voluntary reporting of KD cases by health care providers and local and state health authorities. This system provides CDC with additional information, such as case symptoms and presence or absence of coronary artery abnormalities, that may not be available in hospital discharge data.
- CDC conducts special studies to further describe the incidence and epidemiology of KD in the United States.
In the continental United States, population-based and hospitalization studies estimate an incidence of KD ranging from about 9 to 20 per 100,000 children under 5 years of age. In the year 2016, approximately 5440 hospitalizations with KD were reported among children under 18 years of age in the US; 3935 of these children were under 5 years of age, for a hospitalization rate of 19.8 per 100,000 children in that age group.
For epidemiologic surveillance, CDC defines a case of KD as illness in a patient with fever of 5 or more days duration (or fever until the date of administration of intravenous immunoglobulin if it is given before the fifth day of fever), and the presence of at least 4 of the following 5 clinical signs:
- Cervical lymphadenopathy (at least 1.5 cm in diameter)
- Bilateral conjunctival injection
- Oral mucosal changes
- Peripheral extremity changes
Patients whose illness does not meet the above KD case definition but who have fever and coronary artery abnormalities are classified as having atypical or incomplete KD.