Kawasaki Disease: What it is & How to treat it

Named after Japanese paediatrician Tomisaku Kawasaki who first described it in 1967, Kawasaki disease (aka Kawasaki syndrome or mucocutaneous lymph node syndrome) is a relatively rare disease mostly affecting young children. It is one of the leading causes of acquired heart disease in children globally. 

Kawasaki Disease and COVID-19

In recent weeks, pediatric specialists have noticed an alarming number of children testing positive for COVID-19 presenting symptoms very similar to Kawasaki Disease. On April 27, the Paediatric Intensive Care Society UK (PICS) issued a statement about an urgent alert from the National Health Service England raising the alarm about the number of COVID-19 cases in children presenting symptoms consistent with toxic shock syndrome and Kawasaki Disease. 

What is Kawasaki Disease?

Kawasaki disease (KD) is a severe acute inflammation of blood vessels throughout the body characterized by a prolonged fever. It tends to occur more in early spring or winter. It was thought to be a rare disease which only affected Asian children. But in past decades, KD has become the leading cause of acquired heart disease in children in developed countries. The cause is unknown but could be a reaction by the immune system. Kawasaki disease is not contagious.

Kids under 5 are most commonly affected. Boys are roughly 1.5 times more likely to develop Kawasaki disease than girls. 

Children of Asian ethnicity, particularly Japanese, have greater risks. Children of parents or siblings with Kawasaki disease have a higher risk of developing it. 

Clinical criteria are used to diagnose Kawasaki disease. These include prolonged fever and other characteristic clinical signs.  However, such clinical criteria do not identify all children with KD, especially in those younger than 6 months of age. Doctors may need to rely on laboratory tests and echocardiogram (cardiac ultrasound) to assist in the establishment of a diagnosis. 

Without proper treatment, about 25% of children experience life-threatening complications which usually affect the heart and the coronary arteries, for example aneurysms (bulging of an artery wall), change in heartbeat pattern, inflammation of the heart muscles and heart attack. Timely initiation of treatment has significantly reduced the incidence of coronary aneurysm from 25% to ~4%.

Signs and symptoms of Kawasaki Disease

Your child will suddenly develop these symptoms which will last for 1-2 weeks. 

  • A fever of at least 38°C (100.4°F) persisting for 5 days or more. 
  • A pink rash on the trunk, limbs and groin
  • Conjunctivitis (redness in the whites of, usually, both eyes) without eye secretions.  
  • Red, dry, cracked lips. 
  • Red, bumpy tongue with whiting coating (strawberry tongue).  
  • Swelling in hands and feet with redness on palms and soles. Skin may feel hard and painful to touch. Peeling of skin at hands and feet may be observed within 2-3 weeks after onset of fever. 
  • Swelling and lumps in the neck glands. 

Most kids will present with irritability and fussiness. Some parents may notice swelling and redness around the previous BCG injection site.

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When should you see a doctor?

Visit your doctor quickly if your child shows symptoms, especially if your child is under the age of 6 months. It is important to receive treatment at the earliest (within 10 days from onset of fever) as it may reduce risks of developing serious body damage, including heart complications. 

Fever is the first indication of Kawasaki disease which makes it difficult to spot from that alone. See your doctor if your child has a fever lasting for more than 3 days or any of the following:

  • Red and swollen hands and feet 
  • Rash 
  • Bloodshot eyes (conjunctivitis) 
  • Swollen bumpy tongue (strawberry tongue) 
  • Swollen lymph nodes in the neck 

For atypical or incomplete clinical presentation of KD, doctors may arrange blood tests, urine tests and echocardiograms to guide the diagnosis and evaluate the severity of illness.

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How is Kawasaki Disease treated?

Your child will receive treatment in a hospital as soon as possible to minimize risks of developing serious complications. 

Intravenous immunoglobulin (IVIG)

IVIG is a biological product made from pooled donor plasma. The efficacy of IVIG administered in the acute phase of Kawasaki disease is well established to reduce the prevalence of coronary artery abnormalities. The exact mechanism of IVIG is unknown but it is thought to be related to its counter-inflammation effect. Symptoms should improve within 36 hours after injection. 

Around 10-20% of children with KD have persistent fever or symptoms after one dose of IVIG treatment. Your doctor may advise a second dose of IVIG or switching to other kinds of medicine.  

Aspirin

Aspirin is used for its counter-inflammation effects and ability to prevent blood clot formation. Use of aspirin is considered helpful and safe in children with Kawasaki disease, which is unlikely to be associated with Reye’s syndrome. Your doctor will give your child a high-dose oral aspirin during the acute phase of KD until the fever goes away. Low-dose oral aspirin will be prescribed for a few weeks afterwards or until coronary artery aneurysm subsides.

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Prevention 

There is no way to prevent Kawasaki disease. Children usually recover in 6-8 weeks if given an immediate and proper diagnosis and treatment. Most of them do not develop further or permanent problems from the disease. However, about 1-3% of those who had Kawasaki disease experience a recurrence. 

If a child develops persistent coronary artery abnormality after Kawasaki disease, long-term evaluation and treatment will be required. 

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Dr. Eddie Cheung 張蔚賢醫生 is a specialist in paediatrics. He received his paediatric training in Queen Mary Hospital and post-fellow paediatric cardiology training in Grantham Hospital/ Queen Mary Hospital. He is a Fellow of the Hong Kong College of Cardiology, the Vice President of Hong Kong Society of Paediatric Cardiology and Consultant of Hong Kong Association of Cleft Lip and Palate. He is currently working as Director of Paediatric Centre of HK Medical Consultants and serves as Infection Control Officer at the Hong Kong Adventist Hospital.

This article was independently written by Healthy Matters and is not sponsored. It is informative only and not intended to be a substitute for professional medical advice, diagnosis or treatment. It should not be relied upon for specific medical advice.