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. The standard treatment with intravenous immunoglobulin and aspirin substantially decreases the development of these coronary artery abnormalities.

KS occurs worldwide, with the highest incidence in Japan, and it most often affects boys and younger children. KS may have a winter-spring seasonality, and community-wide outbreaks have been reported occasionally. In the continental United States, population-based and hospitalization studies have estimated an incidence of KS ranging from 9 to 19 per 100,000 children younger than 5 years of age. Approximately 4248 hospitalizations with KS, of which 3277 (77%) were for children under 5 years of age, were estimated among children younger than 18 years of age in the United States in the year 2000. In 2009, the estimated number of hospitalizations with KS was 5447 (standard error [SE]=297); 4040 (SE=227) for children <5 years of age.

CDC uses hospital discharge data, a passive KS surveillance system, and special studies to describe the incidence and epidemiology of KS in the United States. The KS surveillance system has been maintained by CDC since 1976 and is based on voluntary reporting of KS cases by health care providers and local and state health authorities. A standardized case report form is used to collect information on patients.

The KS case report form is available as a pdf document for health-care workers to submit a report. Health-care workers who wish to submit a report can do so by completing either the print form (i.e., print out and complete manually) or the fillable form (i.e., enter the data directly on the computer and then print out the completed form. Note: You may not be able to download and save the completed form if your computer’s software does not allow this feature.) The completed form should be sent to the mailing address provided on the form or sent by fax to (404) 639-3838.

For epidemiologic surveillance, CDC defines a case of KS 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:

• Rash
• Cervical lymphadenopathy (at least 1.5 cm in diameter)
• Bilateral conjuctival injection
• Oral mucosal changes
• Peripheral extremity changes.

Patients whose illness does not meet the above KS case definition but who have fever and coronary artery abnormalities are classified as having atypical or incomplete KS.