Kawasaki disease

A fever lasting five days or more in a young child, with a rash and red eyes. Treatment within ten days protects the heart.

What it is

An inflammatory condition of blood vessels, affecting mainly children under five, with no known cause.

It matters because of the heart. Untreated, around a quarter of children develop aneurysms of the coronary arteries, which can cause heart attacks in childhood or later life. Treated with intravenous immunoglobulin within ten days of the fever starting, that risk falls to around 5 per cent or less.

**The window is what makes this urgent.** Every day of delay after day ten increases the risk, so recognising it early is the entire clinical task.

There is no diagnostic test. It is recognised from a pattern: fever lasting five days or more, plus several characteristic features. The difficulty is that each feature individually looks like a common childhood virus, and children are frequently sent home more than once before anybody assembles the picture.

Incomplete Kawasaki disease, with fewer features, is common in babies under one, who are also at the highest risk of heart complications. A prolonged unexplained fever in an infant should raise it.

All children need an echocardiogram at diagnosis and follow-up scans afterwards.

Signs you might notice

Fever lasting five days or more, often high and not responding well to paracetamol or ibuprofen. This is the essential feature.

Plus several of:

Red eyes without discharge or stickiness.

Red, cracked lips, and a bright red swollen tongue, sometimes called strawberry tongue.

A rash, which can take many forms, often on the trunk and in the nappy area.

Red, swollen hands and feet, followed a couple of weeks later by peeling skin on the fingers and toes.

A swollen lymph node in the neck, usually one-sided.

An extremely irritable child, out of proportion to how they usually are when unwell. Parents consistently describe this and it is a real feature.

See a doctor urgently for any fever lasting five days in a young child, and say the words Kawasaki disease.

How it can affect day-to-day life

The single most useful thing a parent can do is count the days of fever and say the number out loud at every appointment. Day five is the trigger.

Being sent home once with a viral illness does not mean it is not this; the diagnosis often only becomes recognisable as days pass. Going back is the right thing.

Aspirin is used in Kawasaki disease, one of the very few situations where it is given to children, and that is deliberate and correct.

Live vaccinations must be delayed for around 11 months after immunoglobulin treatment, because it interferes with the response. That has to be recorded and communicated to the GP.

Follow-up echocardiograms matter, and families sometimes drop out of them once the child seems well. Coronary changes can appear or evolve after discharge.

There is a related condition, PIMS-TS, seen after COVID infection in children, which shares features and is managed by the same specialists.

Supporting someone well

Count the fever days and say the number. Five days or more in a young child needs medical assessment.

Say Kawasaki disease. It prompts the right examination.

Go back if the fever continues, even if you have already been seen.

Look for the combination: eyes, lips and tongue, rash, hands and feet, neck lump, extreme irritability.

Ask for an echocardiogram at diagnosis, and keep every follow-up appointment.

Record the date of immunoglobulin treatment and tell the GP, so live vaccines are correctly delayed.

Continue aspirin as prescribed, and ask what to do if the child gets chickenpox or flu while taking it.

Ask about long-term heart follow-up before discharge.

Where to get help

A GP practice or A and E urgently for a young child with fever for five days or more.

The paediatric team, and paediatric cardiology for echocardiograms.

Societi, the UK Kawasaki disease foundation, provide information and support.