This child shows the characteristic "strawberry tongue" seen in Kawasaki disease.

Kawasaki disease is a rare condition where the body’s immune system attacks the body’s own tissues. This results in inflammation of blood vessels (including the coronary arteries, which supply blood to the heart) and of the heart muscles. 

Kawasaki disease occurs most frequently in Japan and affects boys more often than girls. Most children with Kawasaki disease are under 5 years of age. It is a poorly understood disease and the cause of it is unknown.

Symptoms of Kawasaki Disease

When Kawasaki disease attacks tissues in various parts of the body, it may lead to:

•  High fever for more than 5 days
•  Skin rash that is not itchy, followed by peeling of the skin around the fingers  and toes 
•  Swelling and redness of the hands and feet
•  Inflammation and redness of the white portion of the eyes - “bloodshot” eyes (conjunctivitis) 
•  Redness of the tongue with prominent bumps on the back surface (this appearance is known as a “strawberry tongue”)
•  Cracked lips
•  Enlarged lymph nodes (lymphadenopathy)
  

The fever is usually over 102°F and can last from several days to a couple of weeks. It is typically not responsive to fever reducers, such as acetaminophen (Tylenol) or ibuprofen (Motrin). Children can be very irritable due to the increased inflammatory process in the body. This is sometimes accompanied with headaches, vomiting or abdominal pain. Some children can have fever for less than 5 days, but not all the classic symptoms of Kawasaki disease. They can be diagnosed with “atypical Kawasaki disease.”

Progression and Possible Complications of Kawasaki Disease

If Kawasaki disease is not treated promptly, the heart may be affected in several ways:

• The heart muscles and valves may function abnormally.
• Fluid may build up in the sac surrounding the heart.  
• The coronary arteries (which supply blood to the heart muscle) may become enlarged and dilated (aneurysm) and eventually develop blood clots. (This occurs in only a small portion of patients.) A blood clot that clogs an artery can cause heart attack or stroke.

Treatments for Kawasaki Disease

There are no tests that can specifically diagnose Kawasaki disease. Blood tests can help suggest this diagnosis. Once Kawasaki disease is diagnosed, treatment should begin immediately to prevent the heart from being affected. Heart-related complications usually occur several days after other symptoms. Rapid recovery from early symptoms is expected following treatment. However, without treatment, patients usually recover eventually, but they continue to have an increased risk for heart problems.

Two drugs are used to treat Kawasaki disease. The first, immunoglobulin (IVIG), must be given through an IV (intravenous) line in the first week or so of illness. This significantly reduces risks to the heart arteries. The condition typically improves within 24 hours after IVIG. This medication can be repeated once if the child does not demonstrate significant improvement.

The other, aspirin, is given initially in high doses to reduce the inflammation. The dosage is then reduced and continued for at least 6 weeks and possibly months to years if heart disease is suspected.

Other drugs, such as acetaminophen (Tylenol) are not effective. The goal of treatment is to prevent the heart arteries from being affected. If they are affected, serious conditions, such as heart attack, may occur. It is not believed that the use of aspirin in this situation results in an increased risk of Reye’s syndrome.

Examining the coronary arteries using ultrasound (echocardiography) is critical. It should be done once the diagnosis is made and usually at least 6 weeks later. If a child has problems with the heart arteries, the patient will need long-term follow up with his or her cardiologist.