Kawasaki Disease

What is Kawasaki disease?

Kawasaki disease is an uncommon childhood illness that causes inflammation of the blood vessels. It most commonly affects children ages 18 to 24 months; it is less commonly seen in people older than age 8. It tends to be severe for several days, but then most children return to normal activities. After your child gets better, the doctor will usually watch him or her for heart problems.

The disease is not contagious and occurs most often in the late winter and early spring.

What causes Kawasaki disease?

Although a specific cause has not yet been identified, researchers suspect Kawasaki disease may be related to a virus or bacteria.

What are the symptoms?

Symptoms of Kawasaki disease include:

• A fever lasting at least 5 days.
• Red eyes.
• A body rash.
• Swollen, red lips and tongue.
• Swollen, red feet and hands.
• Swollen lymph nodes in the neck.

How is Kawasaki disease diagnosed?

Kawasaki disease can be difficult to diagnose. Although there is no specific test for Kawasaki disease, a diagnosis can be made if a child has a fever that lasts at least 5 days and also has 4 of the 5 other symptoms listed above. Less often, a diagnosis is made when a child has a fever that has lasted at least 5 days, two other symptoms from the list above, and some damage to the heart (coronary artery disease).

How is it treated?

Treatment for Kawasaki disease may include medicine given through a vein (intravenous, or IV, medicine) called immunoglobulin (IVIG) to reduce inflammation of the blood vessels, aspirin therapy to lower the risk of blood clots, and possibly blood thinners (anticoagulants) to prevent new blood clots.

Is Kawasaki disease serious?

Most children with Kawasaki disease get better and have no long-term effects, even if they do not receive treatment. However, treatment shortens the illness and greatly reduces the chances of having problems from Kawasaki disease.

About 20% of children who are not treated will have problems in the arteries that supply blood to the heart (coronary artery disease). Weakened coronary arteries may get enlarged or can narrow or develop blood clots. In very rare cases, this can lead to a heart attack.

The risk of heart attack is greatest within 1 year after the illness. However, studies in Japan indicate that children who develop coronary artery damage are more prone to having a heart attack as young adults.¹

The initial symptoms of Kawasaki disease are similar to many other infections or allergic reactions.

The first symptom usually is a sudden, high fever that may be 104°F (40°C) or higher. Unlike fever caused by common viruses, the fever from Kawasaki disease can last more than 10 days if the disease is not treated.

Other symptoms often occur within a few days after the fever. These symptoms include:

• Red, bloodshot eyes, usually without pus or discharge.
• A red body rash that varies in size, shape, and consistency. The rash rarely blisters and is usually most obvious in the torso or groin area.
• Red, swollen, cracked lips and a red ("strawberry") tongue and lining of the mouth.
• Firm, swollen hands and feet with shiny red palms and soles. The skin begins to shed and peel between 1 and 3 weeks after the fever starts. Peeling starts beneath the fingernails and toenails and slowly spreads to the palms and soles.
• Swelling of lymph nodes on one side of the neck. Swelling very rarely occurs on both sides of the neck.

Other symptoms may include:

• Irritability and tiredness.
• Joint swelling and pain. The pain sometimes is very severe; a child may refuse to move or put weight on his or her hands and feet.
• Abdominal pain, vomiting, and diarrhea.
• A rapid heart rate or changes in heart rhythm from heart inflammation.

Other conditions have symptoms similar to Kawasaki disease, including measles, Epstein-Barr infections, scarlet fever, drug reactions, toxic shock syndrome, and juvenile rheumatoid arthritis. It is important for a child with symptoms to see a health professional for diagnosis and proper treatment.

Initial diagnosis

There is no specific test for Kawasaki disease, so diagnosing the disease can be difficult. Doctors use specific criteria developed by the American Heart Association (AHA) to diagnose Kawasaki disease.

Routine lab tests may be done to rule out Kawasaki disease. These tests may reveal another condition, usually a bacterial or viral infection. The most common tests are:

• A complete blood count. This test counts the number of red blood cells and white blood cells.
• Urinalysis. This test can help determine whether illness is present.
• Sedimentation rate. This blood test can help determine whether inflammation is present.

If your doctor suspects Kawasaki disease, he or she may order a C-reactive protein blood test to look for inflammation and an echocardiogram to check for heart problems.

Follow-up tests

Children who have had Kawasaki disease need to have a follow-up exam at 2 to 3 weeks and at 2 to 3 months after the initial disease. Tests done during the exam will include:

• Blood tests to monitor how well the medications are working.
• An echocardiogram to check heart functioning and to detect aneurysms of the coronary arteries.

On rare occasions, other tests are used to see whether there is damage to the heart.

• An electrocardiogram (ECG or EKG) may be used to identify problems with the heart's electrical function.
• A chest X-ray helps check heart size and the chance of heart failure.
• A coronary angiogram may be done if the echocardiogram reveals problems with the coronary arteries.
• A stress test may be done to see how the heart responds to exercise.

Kawasaki disease is treated with medications. Long-term care may be needed and might include continued medication, limited physical activity, and repeated testing.

Early treatment of Kawasaki disease prevents most blood vessel and heart damage. If children with Kawasaki disease are hospitalized and treated within 10 days after the first signs of illness, the risk of heart disease and aneurysms greatly decreases.

Kawasaki disease is best treated by a pediatrician or cardiologist.

Medications

Medications used to treat Kawasaki disease include intravenous immunoglobulin (IVIG), aspirin, and possibly anticoagulants.

Intravenous immunoglobulin (IVIG). Intravenous immunoglobulin (IVIG) is used to reduce inflammation of blood vessels. IVIG usually is given in 1 dose through a vein, over 8 to 12 hours. The treatment usually requires that the child stay in the hospital for at least 24 hours. After IVIG treatment, the illness usually improves very quickly. IVIG works best if it is given before the tenth day of fever. Occasionally, a second dose of IVIG is needed because the first dose did not reduce the fever and inflammation.

Aspirin therapy. At first, high-dose aspirin is used to relieve inflammation and fever. If there are no complications, smaller daily doses are then given for 2 to 3 months to lower the risk of dangerous blood clots. Because of the risk of Reye's syndrome, aspirin should be given only under the guidance of a doctor. If the child is exposed to or develops chickenpox or flu (influenza) while taking aspirin, talk with a doctor right away. For more information, see the topic Reye's Syndrome.

Anticoagulants. Anticoagulants may be used if the child has a large aneurysm. Anticoagulants help prevent new blood clots.

After initial treatment, the child's fever and inflammation should improve, but the child may still be irritable, not have an appetite, and not be very active. The child may also develop deep lines across his or her fingernails (Beau's lines). It may be several weeks before the child feels completely well.

Follow-up treatment

If echocardiogram results from follow-up exams are normal, the child probably will not need further care.

However, if these test results show changes in the coronary arteries, long-term care of the disease may be needed. This care may include:

• Repeated exams and tests every year or every 3 to 5 years, depending on the child's risk for heart problems.
• Continued low-dose aspirin therapy, sometimes combined with other medications that lower the risk of blood clots.
• Limited physical activity.
• Annual flu shot (influenza vaccine(What is a PDF document?)).

What to think about

Treatment with immunoglobulin (IVIG) sometimes interferes with the effectiveness of immunizations against measles, mumps, rubella (MMR)(What is a PDF document?), and chickenpox(What is a PDF document?). MMR and chickenpox immunizations should be postponed for 11 months in children who have received IVIG treatment.

Home treatment generally is not appropriate for children with Kawasaki disease. Treatment starts in the hospital and then is followed by long-term aspirin therapy, which may be given at home.

If your child has symptoms of Kawasaki disease, seek medical attention immediately. Early diagnosis and treatment often prevent life-threatening problems.

If your child has been diagnosed with Kawasaki disease, it is important to follow up with your doctor. An echocardiogram may be done at 2 to 3 weeks and 6 to 8 weeks after the illness to check for aneurysms.

Seek emergency care if your child has been diagnosed with heart problems (coronary artery problems) and has chest pain, is short of breath, faints, or has a lack of energy.

Online Resource

Organizations

• Fever, Age 3 and Younger
• Fever, Age 4 and Older
• Rash, Age 11 and Younger
• Reye's Syndrome

Citations

1. Barron KS, et al. (1999). Report on the National Institutes of Health workshop on Kawasaki disease. Journal of Rheumatology, 26(1): 170–190.

Other Works Consulted

• Mandell BF (2006). Kawasaki disease section of Systemic vasculitis syndromes. In DC Dale, DD Federman, eds., ACP Medicine, section 15, chap. 8. New York: WebMD.

• Newburger JW, et al. (2006). Kawasaki disease. In FD Burg et al., eds., Current Pediatric Therapy, 18th ed., pp. 497–503. Philadelphia: Saunders.

• Oates-Whitehead RM, et al. (2003). Intravenous immunoglobulin for the treatment of Kawasaki disease in children. Cochrane Database of Systematic Reviews(4). Oxford: Update Software.

• Shulman ST (2004). Kawasaki disease. In R Feigin et al., eds., Textbook of Pediatric Infectious Diseases, 5th ed., vol. 2, pp. 1055–1074. Philadelphia: Saunders.

• Sneller MC, et al. (2005). Kawasaki disease section of The vasculitis syndromes. In DL Kasper et al., eds., Harrison's Principles of Internal Medicine, 16th ed., vol. 2, p. 2012. New York: McGraw-Hill.