Kawasaki disease: what it is, symptoms, causes and treatment

The NHS says Kawasaki disease is a rare condition that causes the blood vessels to swell. It says it is not usually serious but can lead to heart problems if it is not treated early.

Great Ormond Street Hospital says it causes swelling of the blood vessels throughout the body, with a high fever and rash, and it can affect the blood vessels supplying the heart muscle (the coronary arteries).

GOSH says it is rare in the UK and affects around eight in every 100,000 children under the age of five. Societi, the UK Kawasaki disease charity, says there are about 1,500 hospital admissions each year in the UK and calls it the leading cause of acquired heart disease in children in the UK.

The NHS says the main symptom is a high temperature that lasts for 5 days or more. Other symptoms may include:

• Swollen glands in the neck.

• A rash.

• The palms of the hands and soles of the feet turning bright red (this may be harder to see on brown or black skin).

• Red (bloodshot) eyes.

• Dry and cracked lips.

• Redness inside the mouth and on the tongue ("strawberry tongue").

• Being very irritable.

GOSH says the symptoms are like a lot of other more common childhood illnesses, and can come and go over days and weeks, with new ones appearing. It describes a fever over 38C for five days or longer, a rash especially on the chest, and palms and soles that turn bright red, become puffy and can peel.

Some children also have painful joints, tummy ache, diarrhoea and vomiting. Children can have Kawasaki disease without showing all the symptoms, often called atypical Kawasaki disease, which is more common in younger children.

Societi suggests that a persistent fever together with two or more of these other symptoms should make you think of Kawasaki disease.

The NHS says to ask for an urgent GP appointment or get help from NHS 111 if you or your child have symptoms of Kawasaki disease, and to call 111 if you need advice for a child under 5.

Because early treatment lowers the risk of heart problems, do not wait for all the symptoms to appear. Call 999 for any child who is very drowsy, struggling to breathe, or has chest pain.

No. The NHS says you cannot catch it from other people. GOSH says it is not contagious or catching and you cannot pass it on to another person, and that no specific bug (bacterium or virus) has been identified.

The NHS says there is no known cause. There is some evidence it may run in families, and it is more common in people from a Japanese or Korean background.

GOSH says it is probably due to a combination of factors. Some children may be genetically more likely to develop it, though no genetic change has been identified, and environmental factors such as infections and the way a child's body responds could play a part. It says links to COVID-19 have not been proven.

GOSH says children under five are most often affected, it is more common in boys than girls, and it can affect anyone of any ethnicity.

The NHS says there is no single test. A healthcare professional will ask about symptoms and examine the child, and may arrange a blood test, a urine test, and tests or scans to check the heart, including an ECG or an echocardiogram.

GOSH says in most cases doctors can diagnose it from the distinctive symptoms, and children usually need tests to find out whether other organs, in particular the heart, are affected.

The NHS says the main treatment is aspirin and medicine given into a vein, usually in hospital for a few days. If a child is at higher risk of getting seriously unwell, such as babies under 6 months or those with severe inflammation or a fever that does not go away, they may also be offered steroid medicine.

GOSH says treatment is usually high-dose immunoglobulin (IVIG) through a drip, with some children also needing steroids. It says aspirin liquid reduces the chance of blood clots. Most children start to feel better a few days after starting treatment, and the earlier treatment starts, the less likely long-term effects are.

The NHS says not to give aspirin to children under 16 unless it is prescribed by a healthcare professional.

The NHS says most people fully recover if it is diagnosed and treated early, but it can sometimes cause damage and swelling in the blood vessels in the heart. If you have complications, you may be more likely to get other heart problems later in life and may need regular check-ups.

GOSH says around 20 to 40 per cent of children develop problems in the blood vessels in the heart muscle, such as a coronary aneurysm, leaky valves or fluid around the heart, which can cause breathlessness and chest pain. If heart problems have not developed within a few weeks of diagnosis, they are unlikely to occur. A second attack is rare.

Children without heart problems usually recover fully and are back to normal within weeks. Those whose coronary vessels were affected need long-term follow-up with heart specialists, with ECG and echocardiogram checks. GOSH's page carries an older review date, so check the current advice with your own team.

The NHS says it usually affects children under the age of 5 but adults can get it too. GOSH says atypical Kawasaki disease is more common in younger children.

For babies under 6 months, the NHS lists them among those at higher risk of becoming seriously unwell, who may be offered steroid medicine.

Kawasaki disease is diagnosed and treated in NHS hospitals, usually by paediatric teams working with heart specialists. Private paediatric care is available, but treatment should not be delayed while arranging it.

The NHS points to Societi, the UK foundation for Kawasaki disease, for information and support.