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Kawasaki disease

Published by Bupa's health information team, August 2008.

This factsheet is for parents of children who have Kawasaki disease, or for people who would like information about it.

Kawasaki disease affects the blood vessels in your child's body, causing them to become inflamed. It can affect any part of the body, and commonly affects the heart. This makes Kawasaki disease the most common cause of acquired heart disease in children in the UK.

Kawasaki disease is relatively rare and mainly affects children aged between six months and five years of age.

About Kawasaki disease
Symptoms of Kawasaki disease
Complications of Kawasaki disease
Causes of Kawasaki disease
Diagnosis of Kawasaki disease
Treatment for Kawasaki disease
Further information
Questions and answers
Related topics
Sources

About Kawasaki disease

Kawasaki disease is an inflammation of the blood vessels (arteries, and to a lesser extent veins) in your child's body (vasculitis). It's named after the Japanese doctor, Dr Tomisaku Kawasaki, who first identified it in 1967.

The disease mainly affects children in the developed world. The highest number of reported cases are in Japan, where there are 30 times more cases than in the UK. The exact cause of the disease is not known at present despite much research.

Most children make a full recovery from Kawasaki disease. However, associated heart complications mean that some children are left with long-term health problems or, very rarely, die because of damage to their heart.

Symptoms of Kawasaki disease

The main symptoms of Kawasaki disease are:

fever (high temperature) lasting longer than five days
conjunctivitis (an inflammation of the transparent layer that covers the white of the eye) affecting both eyes, but with no pus
blotchy, red rash mainly on the trunk of the body which can vary greatly in appearance
changes to the lips or mouth including reddened, dry or cracked lips, and a strawberry-coloured, inflamed tongue often with a sore throat
hands and feet become swollen, red and hard, especially the palms and soles, resulting in peeling skin on the fingertips and toes after several days, this may also affect the groin
large swollen lymph glands on your child's neck, you may feel swollen lumps on either side

Irritable or unreasonable behaviour, which is out of character for your child, is also a frequent symptom.

Other less common symptoms include:

runny nose
cough
sore tummy
vomiting
diarrhoea
painful or swollen joints
yellowing skin (jaundice)

Complications of Kawasaki disease

The most important complication of Kawasaki disease is damage to your child's heart. The arteries in the heart can become inflamed causing a coronary artery aneurysm. This is when a main blood vessel in the heart becomes damaged and swells due to the pressure of blood flowing through it. This creates a balloon-like bulge in the artery which can burst and be fatal. It's estimated that up to 30 percent of children develop a coronary artery aneurysm if Kawasaki disease is left untreated. This risk is greatly reduced by early treatment. The length of time your child's fever lasts is often an indicator of whether or not they will develop a coronary artery aneurysm.

Further damage to the heart can develop in the later stages of the disease as your child's body tries to heal itself. Complications can include:

thrombosis - a blood clot in an artery that can reduce or stop blood flow altogether, in the coronary arteries this can be extremely serious
stenosis - a blood vessel becomes narrowed restricting blood flow, and may cause a heart attack
damage to the heart muscle
heart attack

All these can lead to long-term health problems for your child, and in rare cases, can be fatal. Kawasaki disease very rarely affects other parts of the body, but if it does your child may develop other conditions such as meningitis or gallstones. Occasionally, neurological complications can occur including facial nerve palsy and fits (seizures).

Causes of Kawasaki disease

The cause of Kawasaki disease is not currently known, despite a lot of research. However, it does frequently occur in outbreaks during specific times of the year (late winter and early spring). Because of this it's thought that it may be due to an infection. It has also been suggested that some children may be genetically more susceptible to the infection than others.

Diagnosis of Kawasaki disease

Kawasaki disease can be difficult to diagnose as many of the symptoms are similar to other common childhood diseases, such as measles. Also, there are currently no tests available that can diagnose the condition.

Your GP will ask about your child symptoms and carry out an examination. If your child has had a fever for more than five days, there is no other disease present and has four or more of the main symptoms listed, he or she will make a diagnosis of Kawasaki disease. A fever lasting longer than five days is key to diagnosing Kawasaki disease, as most other childhood disease that are characterised by fever usually settle well before this.

Occasionally, children can have incomplete Kawasaki disease. This means not all the symptoms your doctor would expect to find are present. This may be because not all the symptoms are appearing at the same time, or because the disease has not yet fully developed. The number of these cases has increased in recent years, coupled with the dangerous complications associated with Kawasaki disease, GPs are very careful in making their diagnosis. Your GP may consider a diagnosis of Kawasaki disease even if your child has only two or three of the main symptoms listed above, but has had a fever for more than five days and no other cause for the fever can be found.

If your GP suspects that you child has Kawasaki disease, he or she will be urgently referred to a paediatrician, a doctor specialising in children's health.

The paediatrician will arrange for your child to have an echocardiogram to see if he or she has developed a coronary artery aneurysm. An echocardiogram is a test to see how well the heart is working. It uses an ultrasound probe, which is run over your child's chest to get a moving picture of the heart. Your child will also need to have further echocardiograms after two weeks, then six to eight weeks after diagnosis - although times may vary.

Treatment for Kawasaki disease

As a result of the serious complications associated with Kawasaki disease, treatment should be given as quickly as possible after a diagnosis has been made.

The aim of the treatment is to reduce the inflammation in your child's body to relieve symptoms and to prevent a coronary artery aneurysm from forming. This is done using aspirin and immunoglobulin at the hospital.

Aspirin

Your child will be given four doses of aspirin to take at regular intervals through the day. It's important that you follow your doctor's instructions precisely when giving your child medicines.

Once your child's fever has settled, the dose of aspirin can be reduced. However, he or she will need to continue taking it for a minimum of a further six weeks. The length of time your child will need to continue taking aspirin depends on whether or not his or her coronary arteries have been damaged. If there is damage, your child may need to take aspirin for a much longer period of time.

Immunoglobulin

Immunoglobulin is a specially concentrated antibody from blood donors which is used to give short-term protection against a disease which could cause further health complications. It has been shown to be extremely effective in treating Kawasaki disease, and has been shown to greatly reduce the likelihood of a coronary artery aneurysm.

Immunoglobulin is given as a single dose via an intravenous infusion over 12 hours. This means that the drug will be injected into your child's vein using a cannula (a small plastic tube) and an infusion pump.

The treatment is most effective if given within 10 days of the onset of the disease. The effectiveness of this treatment after this time is not clear, although Immunoglobulin is still given as it is still thought to be useful.

If your child does have lasting heart damage, he or she will need further long-term monitoring and treatment.

Further information

Kawasaki Support Group
024 7661 2178