What Is Kawasaki Disease?

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ThermometerKawasaki disease (KD), although common among children of Japanese and Korean descent, can strike children of any ethnic group. This illness, if left untreated, can cause significant damage to the heart. This is why it is so important to be able to identify warning signs before coronary damage becomes too severe.

Learn how to spot Kawasaki disease in time for treatment to be most effective, in addition to its signs, symptoms, complications, statistics and treatment.

What Is Kawasaki Disease?

Kawasaki disease is a pediatric inflammatory condition that is also recognized by the names: Kawasaki syndrome, lymph node syndrome and mucocutaneous lymph node syndrome. This autoimmune disease is most common in children under the age of five and can cause significant damage and potentially death if left untreated for an extended time.

Named after Dr. Tomisaku Kawasaki of Japan, this disorder was first described by him in 1967 after first being observed in 1961. While this Japanese pediatrician was able to identify this mystery disease and the symptoms which characterize it, he – nor any other researcher, has been able to determine why KD develops.

COVID-19 Linked To Kawasaki-Like Symptoms In Children

15 children in the New York City area and a few in Europe have experienced symptoms similar to Kawasaki disease. These same kids also tested positive for COVID-19 (SARS-CoV-2) or its antibodies. The symptoms of this rare hybrid illness include a fever, rash and the types of swelling and inflammation that are often characterized by KD. While all the symptomatic children have survived (as of May 6, 2020), many were on ventilators or blood-pressure support.

Scientists are currently researching this unexpected connection. As of May 2020, only 2% of COVID-19 cases have been among children (per the CDC), and they experience mild symptoms compared to older populations. So, this appears to be a rare occurrence at the current time, but time will tell.

What Does Kawasaki Disease Do?

As KD sets in, the patient experiences inflammation of the medium-sized blood vessels in the body. Patients may also commonly experience swelling of the skin, lymph nodes, mucous membranes and the heart. When treated promptly, KD does not tend to affect the heart; however, when left unidentified and untreated for a long time, this illness can cause coronary artery aneurysms (in ~25% of untreated cases1). In such young children, these aneurysms are often fatal. Fortunately, with increased exposure to this disorder, many doctors can identify and begin treatment before the disease progresses to this point.


KD is estimated to affect 25 of every 100,000 children less than age 5 in the United States2, but rates of occurrence in foreign countries tend to vary. No one yet understands why this disorder develops or why it is more prevalent in children of particular descent, most specifically Japanese and Korean. Individuals of Afro-Caribbean origin are also at an increased risk for developing this autoimmune disorder. In more recent years, increasing numbers of children of Caucasian descent have been diagnosed with this disorder as well.

Currently, the highest rate of Kawasaki disease diagnosis exists within Japan, with a rate of occurrence at around 250 out of every 100,000 children under the age of five developing this disorder2. 250 is 10 times the number of children diagnosed within the United States. With these statistics holding steady, it’s estimated that more than 1 of every 150 children in Japan will develop this disorder. Of all diagnoses of this disorder made across the world, statistics show that boys are more commonly diagnosed than girls3.

What Is Kawasaki Disease? [VIDEO]

Here’s a video by the KD Foundation illustrating Kawasaki disease in detail and how it affects an individual’s body.

How Does KD Manifest?

Thankfully, there are many symptoms and signs of Kawasaki disease that can tip off parents and pediatricians before the disorder progresses.

High Fever

The primary symptom is a high fever that persists and does not respond to traditional fever-reducing medications. The fever that comes with Kawasaki disease often reaches 104 degrees Fahrenheit or higher and lasts as long as two weeks. Fevers this high can cause significant complications for young children. Such persistent high temperatures should always be treated by a medical professional.

Eye Redness

Eye redness often occurs as a symptom of Kawasaki disease when the tissue around the eye becomes swollen and irritated. This eye redness may be diagnosed as conjunctivitis, iritis or uveitis.

Mouth Swelling

As tissues become swollen and irritated, so do the mucous membranes in the mouth. This type of swelling can be particularly painful and is often accompanied by a variety of other symptoms affecting this area, including redness, swelling, cracking, peeling and fluid buildup in the lips.

Strawberry Tongue

Strawberry tongue is another oral sign of KD. However, it is such a recognizable symptom that it is often identified alone. Strawberry tongue is the term used to describe a tongue with extreme swelling and deep red color.

Lymph Node Swelling

The swelling of lymph nodes is also common with Kawasaki disease, often leading parents to think that their child has a simple infection when, in fact, the condition is much more severe.

Skin Rash

A skin rash is commonly noted in the beginning phases of KD. This rash can take different shapes and appearances and is often difficult to pinpoint. This rash usually starts during the first five days of a fever.

Skin Peeling

Another common sign of Kawasaki disease is skin peeling. It usually happens on the hands, feet and anal regions, with the palms, soles and nails as the most likely affected areas. Skin peeling is often a more advanced sign of KD.

Systemic Symptoms

As the progression of Kawasaki disease continues, internal organs may begin to be affected by the inflammation that is visible on the outside of the body. Some internal symptoms of this disease include pneumonitis, myocarditis, pericarditis, aseptic meningitis, valvulitis, lymphadenitis and hepatitis.

Systemic symptoms are an advanced sign of this autoimmune disorder, and all of these symptoms are serious, requiring immediate medical attention. Most systemic symptoms can be addressed by medical professionals and will eventually relent. The exception to this rule is when the coronary artery is affected. This damage can be significant and can lead to death by a heart attack. The good news is that in most cases, it’s caught before substantial damage to internal systems.

Joint Pain

As swelling occurs with KD, patients may begin to experience swelling within the joints, causing significant pain, particularly in children. This type of joint pain or arthritic symptom is generally experienced symmetrically over the body.


The combination of symptoms that present with Kawasaki disease frequently cause irritability. One can reduce these feelings by making the patient feel as comfortable as possible during treatment.


Tachycardia, also known as a rapid heartbeat, if often seen in patients.

Beau’s Lines

Beau’s lines are deep horizontal grooves or ridges that run across the fingernail. It is important to note that these lines move horizontally rather than vertically like they do naturally as an individual ages.

Difficulty Breathing

The swelling that is characteristic in Kawasaki Disease can often cause difficulty in breathing.


When left untreated for an extended time, difficulties tend to arise from the disease. These can be avoided in most cases by treating the condition as soon as symptoms develop. If treated within ten days, most severe complications such as heart problems will not develop. Usually, KD symptoms disappear completely after two to three days of treatment. Please note that no case of Kawasaki disease is “by the book” and progression can be much slower or much faster than “average.”

Swelling Of The Heart

One of the most concerning side effects of untreated Kawasaki disease is the swelling of coronary arteries, the lining of the heart, the valves of the heart, the muscle of the heart itself and the membrane that surrounds the heart. This type of swelling in such a crucial organ can contribute to a number of undesired effects such as arrhythmia and an inability of the heart to function normally resulting from heart valve concerns.


Another concern that results from untreated Kawasaki disease is the inflammation of blood vessels that can affect the crucial vessels within the body like those that supply blood to major organs.

Can Doctors Test For Kawasaki Disease?

Doctors do not have a test at the moment that can detect Kawasaki disease and instead they must focus on the observable symptoms to make a diagnosis. When symptoms characteristic of this disease such as strawberry tongue are present it can be much easier to identify than when symptoms are more “generic.”  Like many disorders and diseases that pose something of a mystery to the medical community, diagnosis of Kawasaki disease is dependent for the most part on ruling out other potential causes for symptoms.

If a doctor suspects the presence of Kawasaki disease various tests will be performed to monitor its potential progress in addition to ruling out other common diseases.  One of the most important tests performed in suspected cases of Kawasaki disease is heart function monitoring. Monitoring of the heart function allows the doctor to determine whether the disease has advanced so far that heart function has been compromised. Heart function monitoring is less of a diagnostic procedure and more of a monitoring procedure. Diagnostic procedures include urinalysis and blood tests to rule out other diseases such as an allergic reaction to a drug, scarlet fever, Rocky Mountain spotted fever, measles or rheumatoid arthritis.

In order to diagnose this disease doctors most often look for a fever that has lasted for five or more days plus four of the following five criteria: fluid buildup in the lips or mouth or cracking of the lips, swelling or peeling of the hands or feet, a rash on the body trunk, red eyes and a swollen lymph node in the neck.

How Is It Treated?

Due to the fact that Kawasaki disease is still a disease that is not universally recognized or understood it is important that a child suspected of having this disease be seen by a doctor with experience in the area. If a child has been diagnosed with Kawasaki Disease they should be hospitalized and treated by a knowledgeable physician. Treatment should begin as soon as the child is hospitalized in order to prevent the disease from affecting the heart.

Intravenous Immunoglobulin

The first stage of treatment for Kawasaki disease is the administration of Intravenous immunoglobulin. Intravenous immunoglobulin (IVIG) is a blood product that is extracted from blood plasma of blood donors and is most commonly utilized to treat autoimmune diseases, immune deficiencies and acute infections.  When the body no longer has the ability or has a decreased ability to produce antibodies IVIG therapy is used to replace this ability. In cases where a child has Kawasaki disease high doses of IVIG are given and their condition should show improvement within 24 hours. If Kawasaki disease is the only disease being considered and a response is not shown to the initial IVIG therapy a second dose may be administered. Rarely when the disease has progressed to a considerable extent or when it simply shows much resistance to treatment, a third round of IVIG may be administered.

Aspirin Therapy

Salicylate therapy is treatment with a product containing salicylic acid, a compound similar to that found in aspirin.  Aspirin therapy remains a recommended stage of treatment in bringing down a prolonged fever. High doses of aspirin are administered to bring down the initial fever and following fever reduction lower doses are administered for approximately two months to ensure blood clots are avoided. Many individuals question the use of aspirin therapy in young children because of the incidence of Reye’s syndrome associated with aspirin use. Others believe that the administration of aspirin in conjunction with IVIG administration is the most effective method for treating Kawasaki disease. For those who do believe in the use of aspirin therapy it is important to avoid vaccinations which are tied in to the development of Reye’s syndrome, these include: influenza and varicella. These injections should be avoided for the time when a child is undergoing aspirin therapy.

Corticosteroid Use

When Kawasaki disease sets in and shows no signs of leaving, such as recurring symptoms or failure of other treatments, some advocate the use of corticosteroids. While this theory still abounds there is currently much more evidence to indicate that the use of corticosteroids in treatment is contraindicated due to the increased risk it creates for a coronary artery aneurysm. It should also be noted that a controlled trial used to investigate the implementation of corticosteroid use in cases of Kawasaki disease, that the implementation of corticosteroids in addition to IVIG and aspirin therapy showed no significant difference in treatment outcome.

Other Treatments

A handful of other treatments are often implemented in cases of Kawasaki disease; however, these are not specific to the disease, rather they are used to control symptoms. Most commonly eye drops and skin creams can help to improve physical symptoms of the disease.

What Is The Prognosis For A Kawasaki Disease Diagnosis?

When discussing the prognosis for an individual affected with Kawasaki disease it is important to consider the individual case. Depending upon how long the disease has been present and how much damage it has caused to the patient, the prognosis can vary. For cases where the disease was caught in its early stages before significant systemic symptoms developed there is a high likelihood that coronary artery aneurysms will be avoided. For cases where treatment is delayed, the potential for coronary artery damage increases. While the majority of symptoms of Kawasaki will eventually subside, damage that is done to internal organs such as the coronary artery cannot be repaired without medical intervention. In cases where coronary arteries are involved prognosis is not as great. It is estimated that approximately 2% of patient’s diagnoses with Kawasaki disease die as a result of coronary vasculitis. Children who successfully recover from Kawasaki disease should follow up with regular echocardiograms every few weeks to ensure no further progression of the disease. As time goes on these patients should begin to have echocardiograms every year or two to ensure that the cardiac system is still functioning healthily.

Individuals who have been “successfully” treated for Kawasaki disease may also experience a relapse of symptoms following their treatment which requires a second round of treatment. There are also a few rare cases where treatment with IVIG can cause reactions in patients; however, the medical community asserts that this risk is much less than the risk of leaving Kawasaki disease untreated.

Finally, it should be noted that current medical research suggests that the ability to metabolize lipids is altered even after the resolution of Kawasaki disease. This alteration is believed to be persistent long after the disease itself has been resolved.

Is Kawasaki Disease A Real Concern?

So is Kawasaki disease a real concern for parents? While it should be tucked away in the “what if” files for every parent, the actual chances of a child developing this illness are remote. However, any time a parent suspects a child of showing symptoms of this devastating disease, it is always better to be safe than sorry and visit the pediatrician promptly.

KD may not be a significantly widespread or well-known disease, but its damage can be severe and possibly fatal. Education is the key to prevention with this autoimmune disorder because while there is not currently a preventative vaccination available, rapid treatment at the onset of the disease makes all of the difference in a child’s prognosis.

What concerns you most about Kawasaki Disease?

Sources: [1] AHA Journal , [2] MedScape.com, [3] www.ncbi.nlm.nih.gov

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