Kawasaki disease is an uncommon illness that mostly affects children under five years of age.

It is caused by inflammation of blood vessels throughout the body, including those of the heart (the coronary vessels). This inflammation is known as vasculitis. There have been many theories about what causes this, but no single theory is generally accepted as being correct. It is thought that an infection of some sort causes Kawasaki disease, although this has not been proven. Kawasaki disease is not contagious to other children.

There is no simple test for Kawasaki disease. The diagnosis is made by recognising the symptoms and signs of Kawasaki disease in a child who has a persistent fever with no other likely explanation. Blood tests may be helpful. An echocardiogram (ultrasound of the heart) is performed to look for any changes in the coronary (heart) arteries. This is a safe and painless test; it is similar to the ultrasound examination that is used to look at the baby when a woman is pregnant.

Signs and symptoms

The disease usually begins with a high fever (over 39ºC) which continues for at least five days.

Many, but not all, children also develop other symptoms such as:

• large, swollen glands in the neck
• a rash that often peels later on in the illness
• red, shiny or dry, cracked lips
• red, lumpy (strawberry looking) tongue
• red eyes (conjunctivitis) without discharge
• swollen, red hands or feet
• an unusual nappy rash
• joint pains
• extreme irritability (especially in young children).

Other diseases can be confused with Kawasaki disease. They may require different treatment.

The most important part of Kawasaki disease is that it may cause inflammation of the arteries that supply blood to the heart, which can result in an aneurysm (an air bubble in the artery) that can cause heart problems in the future. This occurs in about 25 per cent of patients if they do not receive treatment.

Treatment

The treatment for Kawasaki disease is intravenous (into a vein through a drip, also called IV) gammaglobulin. This is made from donated blood transfusions and contains concentrated amounts of antibodies.

Large doses of intravenous gammaglobulin are usually effective in stopping the fever and other symptoms of Kawasaki disease, and seem to help prevent coronary artery problems as well.

Some parents worry about their child being given blood products. It is important to understand that the risks of this are very low, yet the risks from untreated Kawasaki disease are quite high.

Most children will also be given aspirin for a few weeks after the onset of Kawasaki disease. Aspirin helps to prevent problems with the coronary arteries.

Your child may have to stay in hospital for a few days until the illness begins to settle. Once you go home, it may take three or four weeks for your child to be fully back to normal. Don’t be alarmed if your child gets some peeling of the skin on the hands, feet or groin area – this is very common in the second week of the illness.

Care at home

A small number of children develop problems with either the heart muscle or the coronary arteries. The heart problems appear in the first phase of the illness and this is why the initial echocardiogram is performed. If the test is negative it is very unlikely that problems will develop later, but a further test is usually done after about six to eight weeks.

A small percentage of children will have a recurrence of the symptoms weeks or months later. If this happens, consult your child’s paediatrician.

If your child has Kawasaki disease they will need to be followed up long-term by their GP (family doctor) and a paediatrician.

If your child is due a routine MMR (measles, mumps, rubella) immunisation, this should be delayed until 11 months after the gammaglobulin treatment. 

The vast majority of children with Kawasaki disease recover and live normal lives.

Key points to remember

• The disease starts with a high fever that lasts five days or more.
• It is treated with intravenous gammaglobulin and aspirin.
• Strict follow-up is required by your GP and paediatrician.
• Most children with Kawasaki disease recover completely.