What is Kawasaki disease?
Kawasaki disease is a form of vasculitis, or blood vessel inflammation, that primarily affects children. The inflammation of the blood vessels causes symptoms, including swelling of the hands and feet, redness in the whites of the eyes, swelling and redness of the mouth and lips, and a diffuse rash on the skin. High fever and swelling of the lymph nodes in the neck also are characteristic of this illness. While most children completely recover, the main threat from Kawasaki disease comes from its effect on the heart and its blood vessels (the coronary arteries).
How often does it occur?
Kawasaki disease is fairly uncommon in the U.S. However, Kawasaki disease, together with acute rheumatic fever, are leading causes of acquired heart disease in children in the U.S. and Japan.
Who is affected by Kawasaki disease?
Kawasaki disease occurs more often in Japan than in any other country, but in the U.S. Kawasaki disease can occur in any racial or ethnic group.
Most children who develop Kawasaki disease are under age five. The average age child seen with the illness is two years old. It occurs in boys more often than in girls.
What causes Kawasaki disease?
It is not clear what causes Kawasaki disease. Scientists believe a virus or bacteria may be responsible, but current research is still underway. Kawasaki disease does not appear to be contagious, nor does it appear to be hereditary.
Why is Kawasaki disease a concern?
Kawasaki disease can be a very uncomfortable illness, since it causes fever, as well as irritation and inflammation in many tissues of the body. However, these symptoms usually run their course and resolve within a few weeks. The main concern with Kawasaki disease is heart and blood vessel involvement.
The coronary arteries are the blood vessels that provide the heart muscle with an oxygen-rich blood supply. Kawasaki disease can weaken the wall of one or more of the coronary arteries, causing it to bulge or balloon out. This weakened area is called an aneurysm.
Blood clots can form in the ballooned area and possibly block the blood flow through the coronary artery. When this happens, the heart muscle will no longer receive an adequate supply of oxygen-rich (red) blood, and the heart muscle can be damaged.
The illness may also cause the heart muscle (myocardium) to be irritated and inflamed, as well as the membrane covering the heart (pericardium). Irregular heart rhythms and heart valve problems may also occur with Kawasaki disease.
In most cases, the effects on the heart caused by Kawasaki disease are temporary, and resolve within 5 or 6 weeks. However, coronary artery problems may sometimes persist for longer periods.
What are the symptoms of Kawasaki disease?
The following are the most common symptoms of Kawasaki disease and generally lasting 10 to 14 days.
However, each child may experience symptoms differently. Symptoms may include:
- Moderate-to-high fever (101.0° F to 104.0° F [38.3°C to 40.0°C]) that lasts for at least five days
- Swollen lymph glands in the neck
- Spotty, bright red rash on the back, chest, abdomen and/or groin
- Bloodshot eyes
- Sensitivity to light
- Swollen, coated tongue
- Dry, red, cracked lips
- Red, swollen palms of hands and soles of feet
- Peeling skin around the nail beds, hands or feet
- Swollen, painful joints.
The symptoms of Kawasaki disease may look like other conditions or medical problems. Always consult your child’s health care provider for a diagnosis.
How is Kawasaki disease diagnosed?
Your child’s health care provider will take a medical history, and perform a physical exam. Several of the above mentioned symptoms need to be present for your child’s health care provider to consider Kawasaki disease as the cause for the illness.
Diagnostic tests may also include:
- Electrocardiogram (ECG). A test that records the electrical activity of the heart, shows abnormal rhythms (arrhythmias or dysrhythmias), and detects heart muscle damage. Learn more about electrocardiograms.
- Echocardiogram (Echo). A procedure that evaluates the structure and function of the heart by using sound waves recorded on an electronic sensor that produce a moving picture of the heart and heart valves. Learn more about echocardiograms.
- X-ray. A diagnostic test, which uses invisible X-ray energy beams to produce images of internal tissues, bones, and organs onto film. Learn more about X-rays.
- Complete blood count (CBC). A measurement of size, number, and maturity of different blood cells in a specific volume of blood. The health care provider will look for an elevation in the numbers of white blood cells which normally multiply in the presence of infection and may notice elevated platelet levels with Kawasaki disease as well. Learn more about blood tests.
- Erythrocyte sedimentation rate (ESR or sed rate). A measurement of how quickly red blood cells fall to the bottom of a test tube. When swelling and inflammation are present, the blood’s proteins clump together and become heavier than normal. Thus, when measured, they fall and settle faster at the bottom of the test tube. Generally, the faster the blood cells fall, the more severe the inflammation.
- Urinalysis. Testing of a urine sample for protein, red blood cells, white blood cells, or casts to indicate kidney disease associated with several rheumatic diseases.
How is Kawasaki disease treated?
Specific treatment for Kawasaki disease will be determined by your child’s health care provider based on:
- Your child’s age, overall health and medical history
- Extent of the disease
- Your child’s tolerance for specific medications, procedures, or therapies
- Expectations for the course of the disease
- The family’s opinion or preference.
Once the diagnosis of Kawasaki disease is made, your child’s health care provider may prescribe aspirin to help decrease the inflammation that the illness produces, as well as to prevent clots from forming in the small coronary arteries. However, always check with your child’s health care provider before giving your child aspirin. Some children benefit from an intravenous (IV) medication called gamma globulin that may decrease the risk of the heart being affected. Your child may need to stay in the hospital for a few days if IV gamma globulin is prescribed.
What is the long-term outlook after having Kawasaki disease?
Most children have a full recovery after Kawasaki disease resolves. If an aneurysm of the coronary arteries (heart’s arteries) is detected, echocardiograms will be repeated periodically, sometimes for several years after the illness. Follow-up with a pediatric cardiologist may be needed. Additional treatment may be necessary, including blood thinners in order to prevent clots from forming within the dilated (aneurysmal) coronary arteries. Some heart problems may not be evident right away, so it is important to keep follow-up appointments with your child’s health care provider, even if your child is feeling well.
There is a risk for early coronary artery disease after having Kawasaki disease, including early heart attacks because of microscopic damage to the coronary arteries. Thus, preventive measures such as heart-healthy living habits and regular follow-up with a cardiologist should be continued throughout the lifespan.
It is important to speak with your child’s about his or her specific long-term outlook.