What is Kawasaki disease?

Kawasaki disease affects small and medium-sized arteries in the body. Arteries carry blood from the heart to the rest of the body. Children with this disease have inflammation (swelling) in the walls of arteries. Because the disease also causes 1 or more lymph nodes in the neck to be enlarged, it is also known as mucocutaneous lymph node syndrome.

Kawasaki disease is rare. It usually affects children between the ages of 6 months and 5 years.

What is the cause?

No one knows what causes Kawasaki disease. Some experts think it may be caused by a virus or a bacteria. Others think that chemicals or pollutants may cause it. It does not appear to spread from person to person. Since it is rare for more than one child in the same family to get Kawasaki disease, it does not appear to be genetic.

What are the symptoms?

The symptoms include:

• a fever for 5 or more days
• a skin rash
• swollen, dry, cracked lips
• red, swollen tongue
• red ("bloodshot") eyes
• swollen lymph nodes in the neck
• swelling and redness of the hands and feet. Sometimes the skin of the hands and feet peels, especially around the tips of the fingers and toes.

How is it diagnosed?

Your child's health care provider first needs to check for other diseases that have similar symptoms. If your child has had a fever for many days and also has 4 or 5 of the other symptoms listed above, then your provider will probably diagnose your child with Kawasaki disease. A diagnosis of "atypical Kawasaki syndrome" may be made if your child has a fever and fewer than 4 of the symptoms.

Your child will have tests of the blood and urine. X-rays, electrocardiography (EKG), and echocardiography (a test to show a picture of the heart) may be done to confirm the diagnosis. Some children will also have a lumbar puncture to test a small amount of spinal fluid.

What are the complications of Kawasaki disease?

When untreated, Kawasaki disease can cause many serious problems including:

• Swelling of the heart muscle. The swelling can make the heart pump blood poorly.
• Problems with the coronary arteries. Coronary arteries are the blood vessels that carry blood to the heart muscle. Weak, bulging areas, called aneurysms, can form in the artery. Blood can clot in an aneurysm and eventually block blood flow. When blood flow to the heart is blocked, the heart muscle can be damaged. About 20% of people who have Kawasaki disease will get coronary artery aneurysms.
• Other problems include joint swelling (arthritis), poor digestion, diarrhea, and gallbladder problems. Children with Kawasaki disease can also be very irritable.

What is the treatment?

At first, your child will need to stay in the hospital. If the disease is diagnosed while the child still has a fever, the complications of Kawasaki disease can usually be prevented. Your child will get antibodies through a vein (IV). This treatment greatly reduces the risk of heart problems, especially coronary artery aneurysms.

If your child develops a coronary artery aneurysm, your child will need to start some long-term treatments. This includes taking aspirin to prevent blood clotting. Your child will need to be seen regularly by a pediatric heart specialist (cardiologist).

If your child gets influenza or chickenpox while taking aspirin, a serious complication called Reye's syndrome could develop. Call your health care provider if your child is exposed to either of these diseases. Your provider will consider if getting the chickenpox vaccine is safe for your child. Also, if your child is taking aspirin, he or she should get a yearly flu shot.

As your child improves, tests should show that the inflammation is going away. It is very rare for a child to get Kawasaki disease more than once.

Antibody treatments may interfere with how well the MMR and chickenpox (varicella) vaccines work. If your child gets IV antibodies, he should not get either of these vaccines for 11 months.

When should I call my child's health care provider?

Call immediately if:

• You think your child has Kawasaki disease and he is acting very sick.
• Your child was recently diagnosed with Kawasaki disease (1 to 2 months) and has chest pain, high fever or a return or worsening of the rash.
• Your child is taking aspirin and gets either chickenpox or influenza.

Call during office hours if:

• Your child is taking aspirin and he or she needs to get a flu shot. It is best to get the shot just before flu season. Flu season usually begins in November.
• You would like more information about Kawasaki disease.