Kawasaki Disease

Overview

Kawasaki disease is a rare illness that causes inflammation (swelling and redness) in blood vessels throughout the body. It mostly affects young children, usually under the age of five. The illness starts with a high fever that lasts several days, along with redness, a rash, and other changes you can see. The blood vessels most at risk are the coronary arteries, the tubes that supply blood to the heart muscle. Because of this, doctors treat Kawasaki disease quickly and in hospital. Most children recover fully when treated early.

It is uncommon. Around 8 to 10 in every 100,000 children under five develop it each year in the UK, and rates are higher in some parts of the world such as Japan and Korea. Because it is uncommon, many parents and even some doctors may not think of it at first. That is why knowing the signs is useful.

It mostly affects children between 6 months and 5 years old. Boys are slightly more likely to get it than girls. Children of East Asian heritage have a higher chance of developing it, and it can run in families. It is very rare in teenagers and adults.

Symptoms

Common symptoms

• A high fever that does not go away and lasts five days or longer
• Red, bloodshot eyes with no sticky discharge or pus
• Red, dry, cracked lips and a red, swollen tongue (sometimes called a 'strawberry tongue')
• A rash, often on the chest, tummy, or back, and sometimes in the nappy area
• Swollen, red hands and feet, with peeling skin on the fingers and toes later on
• Swollen, tender glands in the neck, usually on one side
• Being very irritable, unsettled, or hard to comfort

Symptoms in children

• Fever is usually the first sign and often lasts longer than with ordinary childhood illnesses
• Children may be much more grouchy and miserable than the fever alone would explain
• Peeling skin on fingers and toes often appears one to three weeks after the fever began
• Some children have joint pain, tummy pain, vomiting, or diarrhoea
• A few children develop a swollen, painful joint or a sore, red patch where a BCG vaccination scar is

Symptoms in older adults

• Kawasaki disease is very rare in adults and is usually considered only after other causes have been ruled out
• When it does happen in older people, signs can be similar: fever, red eyes, rash, and swollen glands
• Adults with a long-lasting fever and a rash should still be checked by a doctor

Causes

Main causes

• The exact cause is not known. Experts think it is triggered by an infection or something in the environment in a child who is genetically more likely to react this way.
• It is not caused by poor hygiene, bad parenting, or anything a family did or did not do.
• It is not contagious. Children do not catch it from each other, and your child does not need to be kept away from others because of Kawasaki disease itself.

Risk factors

• Age under 5 years, especially between 6 months and 2 years
• Being a boy
• East Asian heritage, or having family roots in Japan, Korea, or China
• A family history of Kawasaki disease in a parent or sibling
• Certain seasons, with more cases seen in winter and early spring

When to see a doctor

See a doctor urgently if:

• Your child has had a fever for five days or more
• Fever plus red eyes, red lips, a rash, or swollen hands or feet, even if the fever has lasted less than five days
• Your child seems very unwell, is hard to wake, or is not drinking
• Your child has chest pain, trouble breathing, or faints

Book a routine appointment if:

• Your child's skin is peeling on their fingers or toes after an illness
• You want to talk through follow-up heart checks or what to watch for at home
• You have questions about school, nursery, sport, or vaccines after recovery

Diagnosis

There is no single test for Kawasaki disease. A doctor makes the diagnosis by examining your child, asking about the illness, and looking for a pattern of signs: a fever lasting five days or more plus several typical features. Because it can look like other illnesses, doctors may check for infections too. Blood tests and a heart scan help confirm the picture and show whether the heart is affected.

Tests that may be done

• A physical examination looking at eyes, mouth, skin, hands, feet, and neck glands
• Blood tests to look for signs of inflammation, such as a raised white cell count or a marker called CRP
• A urine test to rule out other causes of fever
• An electrocardiogram (ECG), a painless recording of the heart's electrical activity
• An echocardiogram (echo), a painless ultrasound scan of the heart that shows the coronary arteries
• Sometimes a throat swab or other tests to rule out infections that can look similar

What to expect at your appointment

In hospital, your child will be checked over carefully and may have several tests, some repeated. The heart scan is the most important one, and it may be done again after a few weeks. Doctors may start treatment before every test result is back, because early treatment matters. It can feel frightening to hear the word 'heart', but staff will explain each step, and you can ask questions at any time.

Treatment

Children with suspected Kawasaki disease are usually cared for in hospital. The aim of treatment is to calm the inflammation quickly and protect the coronary arteries. Treatment is most effective when it starts within the first 10 days of the fever, so it is not something to wait and see about.

Self-care at home

• Keep giving your child plenty to drink; small, frequent sips help if they are off their food
• Offer soft, cool foods if their mouth is sore, and use lip balm for cracked lips
• Give comfort and rest; children with Kawasaki disease are often very unsettled
• Keep a simple note of temperatures and symptoms to share with the medical team
• Follow the hospital's advice about when to return for follow-up heart checks
• Do not give medicines for children without checking with a doctor or pharmacist, especially medicines that contain aspirin or ibuprofen-type painkillers, as these can matter for heart-related conditions

Medical treatments

Treatment is given in hospital. The main treatment is a medicine given through a drip into the vein over several hours, which helps to calm the inflammation and lower the chance of damage to the heart arteries. Children often need a second course. Doctors may also give medicines to ease fever and pain and to help prevent blood clots while the arteries are inflamed. Some children need extra medicines if the first treatment does not work. Heart specialists will monitor your child with scans and decide how long any medicines should continue. Your child may also be offered pain relief and fluids.

When is surgery considered?

Surgery is not needed for most children. In a small number of cases where the coronary arteries have been damaged, a heart specialist team may recommend procedures to widen or bypass narrowed arteries. This is rare, and it usually happens later, after careful monitoring. In the early stages, the focus is on medicines and heart scans rather than surgery.

Living with this condition

Most children are back to their usual selves within a few weeks of treatment, though tiredness and irritability can linger. Skin may peel on the hands and feet, and this is a normal part of recovery. Your child will usually need follow-up appointments with a heart specialist, often starting a few weeks after leaving hospital and continuing for months or sometimes years. These checks are a safety net, not a sign that something is wrong.

Lifestyle tips

• Return to nursery or school when your child feels ready and the medical team agrees
• Encourage normal play and activity, building up gradually after the illness
• Keep up with routine childhood vaccinations; ask your doctor about timing if your child was very unwell
• Note any new symptoms, such as chest pain, breathlessness, or unusual tiredness, and mention them at check-ups
• Keep a copy of your child's hospital summary, as it is useful for future appointments and travel

Diet and exercise

There is no special diet for Kawasaki disease. Offer a normal, balanced range of foods and plenty to drink, and expect your child's appetite to come back gradually. Once your child feels well, normal play, running about, swimming, and sport are encouraged. If the heart arteries were affected, the heart team will tell you whether any activities should be limited, and for how long.

Mental health and emotional wellbeing

A hospital stay, tests, and follow-up appointments can be upsetting for both children and parents. It is normal to feel anxious, especially when the heart is involved. Children may be clingy or worried for a while, and siblings can feel left out. Talk to your child's medical team about any worries, and ask if a play specialist, nurse, or psychologist can help. Parents often find it helps to talk to someone too.

Prevention

Kawasaki disease cannot currently be prevented, because the exact cause is unknown. What you can do is know the warning signs, especially a fever lasting five days or more, and seek medical advice early. Early treatment greatly lowers the risk of heart problems.

Vaccines

There is no vaccine for Kawasaki disease. It is not spread from person to person, so keeping your child away from others will not prevent it. Children should still receive their routine childhood vaccinations as usual, unless a doctor advises otherwise.

Screening programmes

There is no screening test for Kawasaki disease before symptoms appear. After treatment, heart scans and check-ups act as monitoring so any changes in the coronary arteries can be found and managed early.

Complications

If left untreated

• Damage to the coronary arteries, including widening or bulging of the artery wall (called an aneurysm), is the main concern
• Inflammation of the heart muscle or the sac around the heart
• Heart valve problems, which are uncommon
• Changes in heart rhythm
• Without treatment, the risk of heart artery damage is much higher than with early treatment

Long-term outlook

The outlook is good for most children. When treatment is given early, the great majority recover fully with no lasting heart problems. A small number have some damage to the coronary arteries and will need ongoing heart checks, sometimes for many years. With regular follow-up and good care, most of these children live full, active lives. Knowing the signs and acting quickly gives your child the best start.

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