Kawasaki disease

Kawasaki disease is a rare but serious illness. It usually affects younger children under the age of 5 years. The name of the disease comes from Tomisaku Kawasaki, the Japanese doctor who first described it in 1967.

Kawasaki disease causes high fevers that last at least 5 days. If left untreated, about 1 in 5 children with Kawasaki disease will suffer damage to their heart. It can also cause damage to other parts of the body.

The cause of Kawasaki disease is unknown. It is more common in Japan than most other countries. One theory is that a common virus or other common infection causes an over-reaction in the infection-fighting (immune) system of some children. Your child cannot 'catch' Kawasaki disease – it is not contagious.

If Kawasaki disease is not treated, it can last for 10 days or more. If the disease affects the heart, then the damage can be permanent.

Children of Asian and Pacific Island descent are at greater risk. Most children who get Kawasaki disease are under the age of 5 years.

The most striking feature of Kawasaki disease is a high fever that comes and goes for at least 5 days. Children are usually very irritable and easily upset.

Other symptoms of Kawasaki disease include:

• a rash on the body which is often worse in the groin area
• irritated red eyes
• an enlarged reddened tongue (sometimes called 'strawberry' tongue)
• reddened or dry, cracked lips
• redness and/or swelling of the hands and feet 
• swollen lymph nodes in the neck
• peeling of the hands and feet (usually later in the illness).

There are many other possible signs and symptoms including tummy pain, vomiting, diarrhoea, and joint pain and swelling.

If you think your child might have Kawasaki disease you should take them to your doctor straight away.

You should also see your doctor if you are not sure what's wrong but your child:

• looks unwell
• is not improving
• still has a fever after 5 days.

There is no single test that can diagnose Kawasaki disease. Your doctor will consider other possible illnesses as well. The diagnosis can be difficult to make. It is usually confirmed by a children's doctor (paediatrician) in hospital.

Kawasaki disease is usually diagnosed if your child has a fever for at least 5 days and at least 4 of the symptoms listed above. Babies with Kawasaki disease may not have as many of the symptoms as older children. The symptoms may not all be present at the same time. 

Blood tests may help make the diagnosis.

Once diagnosed with Kawasaki disease, your child will need an ultrasound scan of the heart (an echocardiogram) to check whether the disease has affected their heart. This is a safe and painless scan. It is similar to the ultrasound scan women have when pregnant.

If your child is diagnosed with Kawasaki disease, there is special treatment available. It is called immunoglobulin. This is a blood product made of concentrated antibodies from donated blood. Your child will receive it through a vein (intravenously).

Immunoglobulin is very effective at reducing the risk of heart damage. It works best when given within 10 days of the start of the illness. With treatment within 10 days, immunoglobulin reduces the chance of heart damage to 1 in 50. Without treatment the chance of heart damage is about 1 in 5.

Your child's doctor will prescribe aspirin in case there has been heart damage. Your child will keep taking aspirin at least until the ultrasound scan of the heart. Aspirin may increase the risk of Reye syndrome (a rare and serious illness linked to aspirin use in children with fever). See your doctor immediately if your child develops a fever while on aspirin. 

There is no way to prevent Kawasaki disease. Appropriate treatment given early enough in the illness will help prevent complications.

The major complication of Kawasaki disease is heart damage. The most common type of heart damage is caused by irritation or inflammation of the vessels that carry blood to the muscle of the heart. The treatment described above works by reducing the inflammation and preventing the damage.

If damage does occur, your child needs regular health checks by a doctor. After a few years, the heart damage heals in about half of all affected children.

There are other complicated treatments available for children with severe damage.