Kawasaki disease causes inflammation of blood vessels throughout the body.
The cause of Kawasaki disease is unknown but may be associated with an infection.
Children typically have fever, rash, and a red strawberry tongue, and some develop heart complications that rarely can be fatal.
The diagnosis is based on established criteria.
With prompt treatment, nearly all children recover.
Children are given high doses of immune globulin and aspirin.
Kawasaki disease causes inflammation in the walls of blood vessels (vasculitis) throughout the body. Inflammation of blood vessels in the heart causes the most serious problems. The inflammation also can spread to other parts of the body such as the pancreas and kidneys.
Most children with Kawasaki disease are between 1 and 5 years of age, although infants and older children and adolescents can be affected. Roughly one and one half times as many boys as girls are affected. The illness is more common among children of Japanese descent.
Several thousand cases of Kawasaki disease are estimated to occur in the United States every year. Kawasaki disease occurs year-round but most often in spring or winter.
The cause of Kawasaki disease is unknown, but evidence suggests a virus or other infectious organism triggers an abnormal immune system response in genetically predisposed children.
Symptoms of Kawasaki Disease
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Within 5 days, a red, often patchy rash usually appears over the trunk, around the diaper area, and on mucous membranes, such as the lining of the mouth or vagina. The rash may look like hives or may look like the rash caused by measles or scarlet fever. The child has a red throat; reddened, dry, cracked lips; and a red tongue that looks somewhat like a strawberry. Also, the palms and soles turn red or purplish red, and the hands and feet often swell.
The skin on the fingers and toes begins to peel about 10 days after the illness starts. The lymph nodes in the neck are often swollen and slightly tender. The illness may last from 2 to 12 weeks or longer.
Complications of Kawasaki disease
If children are not treated, heart problems may develop, usually beginning 1 to 4 weeks after the illness starts. A few children develop the most serious heart problem, a bulge in the wall of a coronary artery (coronary artery aneurysm). These aneurysms can rupture or provoke a blood clot, leading to a heart attack and sudden death. Treatment greatly reduces the risk of heart complications.
Other problems may include painful inflammation of the tissues lining the brain (meningitis), ears, eyes, liver, joints, urethra, and gallbladder. These symptoms eventually resolve without causing permanent damage.
Diagnosis of Kawasaki Disease
Established criteria
Electrocardiography and ultrasonography of the heart
Laboratory tests
Doctors diagnose Kawasaki disease when children have at least 4 out of 5 defined symptoms (see sidebar How Do Doctors Diagnose Kawasaki Disease?).
Blood tests and cultures of the blood and throat are also done to rule out other disorders that cause similar symptoms (such as measles, scarlet fever, juvenile idiopathic arthritis, and multisystem inflammatory syndrome in children [MIS-C]).
Doctors who specialize in treating children's heart disorders (pediatric cardiologists) or infectious diseases are often consulted.
Once Kawasaki disease is diagnosed, children have electrocardiography (ECG) and ultrasonography of the heart (echocardiography) to look for coronary artery aneurysms, leaking heart valves, inflammation of the sac that surrounds the heart (pericarditis), or inflammation of the heart muscle (myocarditis). Sometimes abnormalities do not appear right away, so these tests are repeated 2 to 3 weeks, 6 to 8 weeks, and perhaps 6 to 12 months after symptoms began. If ECG or echocardiography test results are abnormal, doctors may do a stress test. If an aneurysm is seen during echocardiography, children may have heart catheterization.
Treatment of Kawasaki Disease
High doses of immune globulin and aspirin
Treatment for Kawasaki disease is started as soon as possible. Treatment given within the first 10 days of symptoms significantly reduces the risk of coronary artery damage and speeds the resolution of fever, rash, and discomfort.
aspirin is lowered but still given for at least 8 weeks from the beginning of illness. If there are no coronary artery aneurysms and signs of inflammation are gone, aspirin may be stopped. However, children with coronary artery abnormalities require long-term treatment with aspirin.
Because aspirin use slightly increases the risk of Reye syndrome in children who have influenza or chickenpox, doctors make sure to give children on long-term aspirin therapy the recommended annual influenza vaccination. All children should also receive the varicella (chickenpox) vaccineaspirin to lessen the risk of Reye syndrome.
Children with large coronary aneurysms may be treated with medications that prevent the blood from clotting (anticoagulants).
Prognosis for Kawasaki Disease
With treatment, children recover completely if their coronary arteries are not affected. For children with coronary artery problems, the outcome varies with the severity of the disease. However, with early treatment, almost no children with Kawasaki disease in the United States die.
Without treatment, some children die. Of the children who die, death nearly always occurs in the first 6 months but can occur as long as 10 years later.
About two thirds of the aneurysms go away within 1 year. Large aneurysms are more likely to remain. However, even when aneurysms go away, children have an increased risk of heart problems in adulthood.
