What is ​​Kawasaki Disease and How to Manage It

​Kawasaki disease is an illness that usually affects children less than 4 years old, though older children may get it too.

In Kawasaki disease, also known as mucocutaneous lymph node syndrome, small- and medium-sized arteries in different parts of the body get inflamed. Lymph nodes are also affected.

Kawasaki disease is named after the Japanese doctor Tomisaku Kawasaki who first described the disease in 1967.

There is no special test that can diagnose Kawasaki Disease. A diagnosis of Kawasaki disease is mainly based on the following clinical signs and symptoms:

• High fever for at least 5 days
• Red eyes (conjunctivitis)
• Red, cracked lips and red-coloured, swollen tongue
• Skin rash
• Swollen lymph nodes in the neck
• Swollen and red palms of hands and soles of feet, peeling of the skin of the extremities can occur later
• Other symptoms include abdominal pain, joint pain, diarrhoea and vomiting.

At a later stage of the illness, the patient may present skin peeling on the toes and fingers, especially at the tips.

Symptoms of Kawasaki disease will usually resolve with treatment or with time. However, in some patients, complications, especially those related to the heart, may develop.

The cause of Kawasaki disease is unknown though doctors believe the inflammation could be due to the body’s overreaction to a viral or bacterial infection. Most patients have a complete recovery and go on to lead normal and healthy lives.

“The incidence of Kawasaki disease in Singapore is estimated at 51.4 per 100,000 children ≤ 5 years of age,” says Clinical Associate Professor Tan Teng Hong, Senior Consultant, Cardiology Service, KK Women’s and Children’s Hospital (KKH), a member of the SingHealth group.

“KKH sees an average of 120 new cases per year of which about half are below the age of 21. The younger the age group, the higher the incidence, and more than 90 per cent of our patients with Kawasaki disease are 5 years old or younger,” adds A/Prof Tan.

Age is not the only risk factor for Kawasaki disease. Asians have been found to be more prone to this inflammatory disease than Caucasians.

Among Asian countries, Japan has a higher incidence than countries such as China and Taiwan, which have a rate similar to Singapore. The incidence of Kawasaki disease in Japan is above 200 per 100,000 children ≤ 5 years of age while in the USA, it is 19.6 and in Australia it is 5.5 per 100,000 children ≤ 5 years of age.

Patients with Kawasaki disease can develop heart complications such as mild dilatation of the coronary arteries. These abnormalities, usually diagnosed in the first two weeks of the illness, are likely to resolve spontaneously within a few weeks or months.

However, some patients may suffer from more serious complications such as coronary aneurysm, which can result in further heart problems.

“About 30 per cent of patients develop coronary abnormalities and about 5 per cent develop coronary aneurysm, which is a more significant and long-term problem,” says Clin Assoc Prof Tan.

“Coronary aneurysm can lead to coronary insufficiency due to blockage, decreased cardiac function (weak heart), abnormal heart rhythms (arrhythmia) or sudden death,” he added.

Other potential heart complications, though less common, include acute myocarditis (inflammation of the heart muscle), valve leakage, pericardial effusion, arrhythmias (abnormal heart rhythms) and acute myocardial infarction (heart attack).

“Children who are younger, who show atypical presentation of Kawasaki disease, who are resistant to intravenous immunoglobulins, or those who have had recurrent Kawasaki disease, will have a higher risk of developing heart problems,” says Clin Assoc Prof Tan.

Kawasaki disease treatment generally entails hospitalisation for 3-7 days.

Your child may be given high doses of aspirin to lower the fever. Aspirin will also help with the rash and prevent your child's blood from clotting too easily. The dose of aspirin will be reduced after the fever comes down and may be continued for several weeks to reduce the risk of heart problems.

Your child may also be given a special medicine derived from blood called immunoglobulin or IVIG, which will help reduce the risk of developing heart problems.

IVIG can only be given in the hospital and will be given over several hours through your child's veins. There may be some redness, swelling or infection developing at the drip site. The doctors and nurses will check the drip site regularly to monitor for these complications.

After Kawasaki disease treatment, the patient will require follow-up heart ultrasound scans (echocardiograms) to ensure there are no complications from the disease.