What Is Kawasaki Disease?

As news has spread of an inflammatory condition affecting children, possibly linked to COVID-19, many parents have become worried. The condition, named “Pediatric Multi-System Inflammatory Syndrome Potentially Associated with COVID-19” by the New York State Department of Health, has affected at least 73 children as of May 8, 2020, and may be linked to other cases across the country as well as in the United Kingdom and Europe.

One defining characteristic of the condition is that its symptoms resemble many of the symptoms of Kawasaki disease. “This syndrome has features which overlap with Kawasaki disease and toxic shock syndrome,” explains a May 2020 memo from the New York State Department of Health. “Inflammatory markers may be elevated, and fever and abdominal symptoms may be prominent.”

Although the cause is still unknown, Kawasaki disease is characterized by abnormal immune system activation. It is believed that an infectious trigger in those with a genetic predisposition plays a role. Kawasaki disease is not contagious. With treatment, the majority of people with Kawasaki disease are able to recover.

Characteristics, Symptoms, and Complications

According to the National Institutes of Health (NIH), the classic characteristics of Kawasaki disease include swelling of the mouth, eyes, and lips, as well as a rash on the hands and feet. Many sufferers will also have swollen lymph nodes. But there are many other symptoms that have been linked to Kawasaki disease.

Most Common Symptoms

Eighty percent to 99% of people with Kawasaki disease will have these symptoms, according to NIH:

• Lip inflammation
• Pink eye (conjunctivitis)
• Swollen lymph nodes (lymphadenopathy)
• Reddening of the skin (erythema)
• Protein in the urine
• Sore throat
• Rash on skin
• Inflammation of blood vessels (vasculitis)

Other Common Symptoms

Thirty percent to 79% of people will have these symptoms, according to NIH:

• Stomach/abdominal pain
• Abnormalities of the heart valve muscle
• Changes in fingernail color
• Joint inflammation (arthritis)
• Diarrhea
• Fluid retention (edema)
• Fever over 102.2 degrees F
• Fatigue
• Tongue inflammation
• Increased white blood count
• Pericarditis (swelling of the heart membranes)

Less Common Symptoms

The following symptoms are a sampling of symptoms that do occur, but with less frequency—affecting 5% to 29% of people with Kawasaki disease, according to the NIH. Although less common, these symptoms are among the most serious, and often require medical attention and/or hospitalization.

• Abnormal heart rate
• Pain in the joints
• Inflammation of the gallbladder
• Congestive heart failure
• Cranial nerve paralysis
• Inflammation of the liver
• Jaundice
• Meningitis
• Inflammation of the heart muscle
• Nausea and vomiting

Other notable symptoms that often affect children, according to the Kawasaki Disease Foundation, include a fever lasting at least five days; dry, cracked lips; and peeling of the skin on the hands, feet, fingers, and toes.

Causes of Kawasaki Disease

At this time, the exact cause of Kawasaki disease is not known. The disease is characterized by inflammation in the blood vessels, but what triggers this inflammation is unclear.

Experts believe that various viruses may trigger it, but the National Institutes of Health (NIH) explains that as of now, no specific virus or infection has been identified. Additionally, genetics may play a role, though experts are not certain of what that role may be. The disease may also be an immunological response, says NIH.

Risk Factors for Kawasaki Disease

The following factors may make you or your child more susceptible to Kawasaki disease:

• Genetics: The ITPKC gene may play a role in Kawasaki disease, according to the National Institutes of Health (NIH). “Researchers suggest that the ITPKC gene variation may interfere with the body's ability to reduce T cell activity, leading to inflammation that damages blood vessels and results in the signs and symptoms of Kawasaki disease,” NIH explains.
• Age: Children under the age of five are more susceptible to Kawasaki disease, although older children and teens also get diagnosed with it. Though rare, adults can have Kawasaki disease as well.
• Ethnicity: The disease more typically affects children of Asian or Pacific Island descent. According to NIH, for example, about 1 in 10,000 children under 5 get Kawasaki disease in the United States and Western countries, whereas the disease is 10 to 20 times more likely to strike a child of East Asian descent.
• Other risk factors: Sex may play a role who gets Kawasaki disease, as boys are slightly more likely to be affected. In addition, family trends may be a factor. For example, according to NIH, children whose parents have had Kawasaki disease are twice as likely to get it; if their siblings had it, they are ten times as likely to get it. 

Diagnosis

There is no one specific way to test for Kawasaki disease. If you suspect that your child has it, you should contact your doctor right away for an assessment. Here’s what may happen when you visit your doctor:

• Your doctor will rule out other diseases with similar symptoms to Kawasaki disease, such as toxic shock syndrome, scarlet fever, measles, and juvenile rheumatoid arthritis.
• Your doctor may order blood tests to look at your child’s white blood cell count, iron levels, and inflammation.
• Your doctor may perform an electrocardiogram or echocardiogram to look for abnormalities in the way your child’s heart is functioning.

Treatment

The good news is that with treatment, most cases of Kawasaki disease are treatable. Although a small number of children do die from Kawasaki disease, most survive with prompt and proper treatments.

Usually, your doctor will want to begin treatment as soon as a diagnosis is made, and hospitalization is usually required.

Gamma globulin treatments are the most common treatments for Kawasaki disease. Gamma globulin proteins are administered intravenously to your child, usually in high doses. According to NIH, improvement is usually seen within 24 hours of treatment.

Aspirin treatments are also given in most cases, as it decreases inflammation, reduces swelling, and brings down fever. Low dose aspirin may be given for weeks after initial treatment.

In rare cases, your child may develop blood vessel or heart problems as a result of Kawasaki disease. In these cases, your child will be referred to a pediatric cardiologist, who may recommend specific treatments.

The Link Between Kawasaki Disease and COVID-19

At this time, the information we have about Kawasaki-like disease linked to COVID-19 is very new and constantly evolving. As of this writing, doctors in New York as well as around the country have seen numerous cases of children exhibiting signs of Kawasaki disease, toxic shock syndrome, and other concerning symptoms.

Pediatric Multi-System Inflammatory Syndrome

The hypothesis so far is that these mysterious inflammatory symptoms, which present very similarly to Kawasaki disease, are now known as “pediatric multi-system inflammatory syndrome potentially associated with COVID-19” and may be linked to COVID-19 infection.

The reason doctors suspect a link to COVID-19 is that most patients presenting with this new syndrome have either tested positive for COVID-19 or tested positive for antibodies of the virus (meaning that they may have previously been infected with it).

The New York State Department of Health is urging pediatricians who come across children with these symptoms to promptly refer families to specialists, as this syndrome requires immediate expert care and hospitalization. “Early recognition by pediatricians and prompt referral to an in-patient specialist, including to critical care is essential,” explains the memo.

As Steven Kernie, MD, of Columbia University and NewYork-Presbyterian Morgan Stanley Children’s Hospital, explains to The New York Times, this new syndrome doesn’t affect the heart in the same way as Kawasaki syndrome.

Whereas Kawasaki disease is known to cause coronary aneurysms, pediatric multi-system inflammatory syndrome potentially associated with COVID-19 primarily causes coronary artery inflammation, as well as inflammation of blood vessels, explains Kernie. This new condition also causes symptoms of shock, which is not generally seen with Kawasaki disease.

The information in this article is current as of the date listed, which means newer information may be available when you read this. For the most recent updates on COVID-19, visit our coronavirus news page.