Kawasaki Disease

Kawasaki disease is an acute childhood illness that causes inflammation of the blood vessels in many areas of the body. If not treated early, it can cause damage to the coronary arteries, which supply the heart with oxygen.

With early treatment, most children begin to feel better in a few days, with a low likelihood of long-term heart issues. Most children are back to normal health in about six to eight weeks.

Kawasaki disease is the most common form of acquired heart disease in the United States and Japan. It is most common in children under age 5, although children of any age can develop it. Boys are 1.5 times more likely to develop the disease than girls.

There’s no definitive test for Kawasaki disease, and its symptoms often resemble those of other childhood diseases.

The disease is not contagious (spread from person to person). Outbreaks have been reported in waves within geographical areas, and the disease tends to occur more frequently in winter and early spring.

The symptoms of Kawasaki disease usually appear in phases, and can change or evolve over time.

Symptoms of classic Kawasaki disease include:

• High fever
• Rash
• Redness or swelling of the hands, followed by peeling skin on the fingers or toes
• Bloodshot eyes (both eyes), without drainage
• Red, cracked lips
• Strawberry tongue (a red, swollen tongue)
• Enlarged lymph node in the neck

Some children with Kawasaki disease may also have the following associated symptoms:

• Irritability
• Joint pain or temporary arthritis
• Diarrhea or vomiting
• Abdominal pain

Despite decades of research, the causes of Kawasaki disease are still unknown. We suspect there could be multiple reasons that people develop this condition.

Because no bacteria or virus has been proven to cause Kawasaki disease, some experts believe that Kawasaki disease is an immune reaction that children may have to a variety of infectious agents. Genetic susceptibility may play a role.

Kawasaki disease occurs more often in Japan than in any other country. Children of Asian or Asian-American heritage have a higher risk of Kawasaki disease regardless of where they live — although Kawasaki disease can occur in any racial or ethnic group.

There is no specific test for Kawasaki disease. One challenge in diagnosing Kawasaki disease is distinguishing it from other childhood diseases with similar symptoms.

To be diagnosed with classic Kawasaki disease, a child must have a high fever for at least five days, as well as four of the five classic symptoms.

It is possible to have Kawasaki disease without having all of the symptoms. Such cases are called incomplete or atypical Kawasaki disease. This is most common in infants younger than 6 months.

To arrive at a diagnosis, the doctor will start by taking a full medical history and conducting a thorough physical exam.

Diagnostic tests may include:

• Electrocardiogram (ECG or EKG)
• Echocardiogram (cardiac ultrasound)
• Blood tests

The standard treatment for Kawasaki disease is IVIG (intravenous immunoglobulin). It is most effective in preventing long-term heart damage when started within 10 days of the onset of illness. IVIG can shorten the duration of the fever and decrease the risk of developing an abnormal enlargement of the coronary vein (aneurysm). Because IVIG is given intravenously (through a vein), your child will need to stay in the hospital during treatment and until their fever goes away.

Your child’s clinician may also recommend high doses of aspirin to control inflammation and fever.

Most children respond to their first treatment with IVIG. Some children continue to have a fever despite IVIG treatment, and may need additional treatment.

If your child develops coronary problems from Kawasaki disease, they may need to take blood-thinning (anticoagulant) medications — either on a short-term or lifelong basis — to reduce the risk of a clot in the coronary vein.

Most children make a full recovery after Kawasaki disease, especially when diagnosed and treated early. Your child may be tired and irritable for a few weeks after they come home and may not feel 100 percent better until six to eight weeks after the illness.

After having Kawasaki disease, the frequency of follow-up and types of testing will be based on your child’s specific needs. If your child never developed coronary artery enlargement, they will not need long-term follow up by a cardiologist.

If your child developed an aneurysm from Kawasaki disease, they will need cardiology follow up. Testing may include echocardiograms and other types of imaging.

Aneurysms may also occasionally occur in other arteries, such as those supplying the arms, legs, or kidneys. These aneurysms rarely cause symptoms, and are generally seen only in patients who have giant coronary aneurysms.

The experienced team members of the Boston Children’s Hospital Kawasaki Disease Program provide coordinated care for children with Kawasaki disease — during the illness’ acute phase and for short- and long-term follow up.

Each year, our program — staffed by expert cardiologists, rheumatologists, and a pediatric nurse practitioner — treats more than 65 patients who have confirmed or suspected Kawasaki disease. We follow more than 1,500 children and young adults who have had Kawasaki disease in our outpatient Heart Center.

The Kawasaki Disease Program serves as a national and international resource for parents and physicians. We provide families with a wealth of information and support — and we help pediatricians and other specialists to confirm and treat this hard-to-diagnose illness.