Kawasaki disease affects children. It is also known as Kawasaki syndrome or mucocutaneous lymph node syndrome. Kawasaki disease leads to swelling (inflammation) of the body’s tissues and if left untreated, can lead to inflammation of the heart and the coronary arteries. This inflammation can lead to long-term heart problems such as blood clots, aneurysms, or a heart attack.

Kawasaki disease most often affects the coronary arteries, usually by weakening their walls. If an artery’s wall is weakened, the pressure of blood passing through it forces the artery to bulge outward, forming what you might think of as a thin-skinned blister. This is called an aneurysm. If a blood clot forms in the aneurysm, it can block the artery, leading to a heart attack. In rare cases, the aneurysm may burst.

Kawasaki disease may also cause inflammation of the heart muscle (called myocarditis) or the sac surrounding the heart (called pericarditis). It can also lead to abnormal heart rhythms (arrhythmias).

For most children, the heart problems go away after 5 or 6 weeks, and there is no lasting damage. In some children, the coronary arteries are damaged forever.

Who is at risk for Kawasaki disease?

Kawasaki disease usually affects children younger than 5 years old. It occurs more often among boys. It is also more common in people of Asian descent, but it can occur in any racial or ethnic group. Kawasaki disease is not contagious, but doctors think some sort of germ or virus causes the disease because it can occur in outbreaks (usually in the late winter or spring).

About 2,500 children are diagnosed with Kawasaki disease in the United States each year, but less than 1% will die of complications from the disease. It is very rare for more than one child in a family to develop Kawasaki disease and it rarely recurs.

What are the symptoms of Kawasaki disease?

The signs and symptoms of Kawasaki disease may include

• A very high fever (up to 104 degrees) that lasts for at least 5 days
• Irritability
• A red rash on the back, chest, and stomach area
• Red (bloodshot) eyes
• Swollen fingers and toes
• Swollen glands in the neck
• A coated and swollen tongue that looks like the surface of a strawberry (called strawberry tongue)
• Red, dry, and cracked lips
• A sore throat
• Joint pain and swelling

Because many of these signs and symptoms can also look like the symptoms of measles, scarlet fever, strep throat, or allergies, it is important that you take your child to a doctor right away. In as many as 20% of children, Kawasaki disease affects the heart, including damage to the coronary arteries or the heart muscle itself.

How is Kawasaki disease diagnosed?

Doctors will ask about the child’s symptoms and perform a physical exam. Blood tests, including a complete blood count (CBC), may be performed. Other diagnostic tests can let doctors see if there is damage to the heart or the coronary arteries.

• Electrocardiography (ECG or EKG), which is used to check for an irregular heartbeat (arrhythmia) and stress on the heart.
• Echocardiography, which is used to see valve function, heart wall motion, heart size, and coronary artery size.
• A nuclear stress test, which uses a harmless radioactive substance that is injected into the bloodstream to show how blood flows through the arteries.

How is Kawasaki disease treated?

High-dose aspirin can help decrease aneurysm formation and help to reduce the fever, rash, and the joint swelling and pain. Aspirin also thins the blood, which can stop blood clots from forming. If given early enough, a medicine called intravenous gamma globulin can sometimes decrease the risk of damage to the coronary arteries.

Children with no lasting damage to the heart or coronary arteries should recover completely. They will need to see a doctor who treats children with heart problems (a pediatric cardiologist) regularly for about a year.

Children who have mild damage to the coronary arteries will need to see a pediatric cardiologist regularly for at least a year. After that time, the doctor may want to see the child every 3 to 5 years for a check-up and to monitor the exercise your child can safely do.

Children with severe damage to the coronary arteries will need to see a pediatric cardiologist regularly and have follow-up tests, such as electrocardiography or echocardiography, until they are about 10 years old. After that, they may need to go back to the doctor for a stress test every year to monitor the heart and determine which physical activities they can safely do.

Surgery or a percutaneous coronary intervention may also be used to treat any long-term effects of Kawasaki disease.