About Kawasaki Disease
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.
The CDC standardized KD case report form is available as a pdf document for healthcare workers to submit a report. Healthcare workers who wish to submit a report can do so by completing either the print form print formpdf icon (i.e., print out and complete manually) or the electronic formpdf icon (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 404-471-8768.
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.
Kawasaki disease causes swelling (inflammation) in children in the walls of small to medium-sized blood vessels that carry blood throughout the body. Kawasaki disease commonly leads to inflammation of the coronary arteries, which supply oxygen-rich blood to the heart.
Kawasaki disease was previously called mucocutaneous lymph node syndrome because it also causes swelling in glands (lymph nodes) and mucous membranes inside the mouth, nose, eyes and throat.
Children with Kawasaki disease might have high fever, swollen hands and feet with skin peeling, and red eyes and tongue. But Kawasaki disease is usually treatable, and most children recover without serious problems if they receive treatment within 10 days of onset.
To receive a diagnosis of Kawasaki disease, a child usually will have a fever greater than 102.2 F (39 C) for five or more days and at least four of the following signs and symptoms.
- A rash on the main part of the body or in the genital area
- An enlarged lymph node in the neck
- Extremely red eyes without a thick discharge
- Red, dry, cracked lips and an extremely red, swollen tongue
- Swollen, red skin on the palms of the hands and the soles of the feet, with later peeling of skin on fingers and toes
The symptoms might not occur at the same time, so it’s important to let your child’s health care provider know about a sign or symptom that has gone away.
Other signs and symptoms that might develop include:
- Abdominal pain
- Joint pain
Children with a high fever for five or more days who have fewer than four of the above signs and symptoms might have what’s known as incomplete Kawasaki disease. Children with incomplete Kawasaki disease are still at risk of coronary artery injury and still require treatment within 10 days of the onset of symptoms.
Kawasaki disease can have symptoms similar to that of multisystem inflammatory syndrome in children, which has occurred worldwide in children with COVID-19. Children with these symptoms will likely be checked for COVID-19, as well.
When to see a doctor
If your child has a fever that lasts more than three days, contact your child’s health care provider. Treating Kawasaki disease within 10 days of when it began may greatly reduce the chances of lasting damage to the coronary arteries supplying the heart muscle.
No one knows what causes Kawasaki disease, but scientists don’t believe the disease is contagious from person to person. Some think that Kawasaki disease happens after a bacterial or viral infection, or that it’s linked to other environmental factors. Certain genes might make children more likely to get Kawasaki disease.
Three things are known to increase a child’s risk of developing Kawasaki disease.
- Age. Children under 5 years old are at highest risk of Kawasaki disease.
- Sex. Boys are slightly more likely than girls to develop Kawasaki disease.
- Ethnicity. Children of Asian or Pacific Island descent, such as Japanese or Korean, have higher rates of Kawasaki disease.
Kawasaki disease tends to occur seasonally. In North America, it usually occurs in the winter and early spring.
Kawasaki disease is a leading cause of acquired heart disease in children in developed countries. However, with treatment, few children have lasting damage.
Heart complications include:
- Inflammation of blood vessels, usually the coronary arteries, that supply blood to the heart
- Inflammation of the heart muscle
- Heart valve problems
Any of these complications can damage the heart. Inflammation of the coronary arteries can lead to weakening and bulging of the artery wall (aneurysm). Aneurysms increase the risk of blood clots, which could lead to a heart attack or cause life-threatening internal bleeding.
For a small percentage of children who develop coronary artery problems, Kawasaki disease can cause death.