Kawasaki Disease vs. MIS-C: Symptoms, Treatment & Causes

Kawasaki disease facts

A non-blistering rash is one of the clinical features of Kawasaki disease.

Kawasaki disease is a syndrome of unknown cause that mainly strikes young children.
Kawasaki disease symptoms and signs include
- fever and
- redness of the eyes, hands, feet, mouth, and tongue.
The disease can be treated with high doses of aspirin (salicylic acid) and gamma globulin.
Kawasaki disease symptoms usually resolve within a month or two, but the disease should be considered a "lifelong disease" because monitoring for late-onset heart artery changes is necessary.
Some children with Kawasaki disease suffer coronary artery lesions.
Multisystem inflammatory syndrome in children (MIS-C) is different but with similar symptoms to Kawasaki disease.

What is Kawasaki disease, and how do doctors diagnose it?

The definition of Kawasaki disease is an uncommon illness in children that is characterized by high fever of at least 5 days' duration together with at least four of the following five symptoms and signs that occur in the acute phase:

Inflammation with reddening of the whites (conjunctivae) of the eyes (conjunctivitis or pinkeye) without pus
Redness or swelling of the feet and/or hands, or generalized skin peeling
Rash on body and/or genital area
Lymph nodes swelling in the neck
Cracking, inflamed lips or throat, or red "strawberry" tongue

Doctors use the above criteria to make a diagnosis of Kawasaki disease. Some investigators consider this phase 1. Phase 2 signs and symptoms may occur during the disease and may include:

Skin peeling (from red palms and finger tips and reddish swollen feet)
Diarrhea
Vomiting
Abdominal pain
Joint pain

In phase 3, signs and symptoms slowly abate if there are no complications. However, the person may have irritability, tiredness, and low energy for 1-2 months.

Doctors sometimes use the terminology "incomplete Kawasaki disease" for patients who receive a diagnosis with only some features of classical Kawasaki disease.

Most patients (about 77%) are under 5 years of age with a peak incidence at 18 months of age. It is the most common acquired heart disease in children. Complications may include long-term effects of heart problems and coronary artery abnormalities like vasculitis.

What is mucocutaneous lymph node syndrome?

Mucocutaneous lymph node syndrome is the original name for Kawasaki disease. The original name was quite descriptive because the disease is characterized by the typical changes in the mucous membranes that line the lips and mouth and by the enlarged and tender lymph nodes. Kawasaki disease is also termed infantile polyarteritis.

Kawasaki Disease Symptoms and Signs

High fever is a prominent symptom in children with Kawasaki disease. The fever is persistent and lasts for at least five days. Nonspecific symptoms can precede or accompany the fever, including

fussiness,
nausea,
vomiting,
runny nose,
cough,
diarrhea,
joint pain,
abdominal pain,
and decreased intake of food and liquids.

Learn more about Kawasaki disease symptoms and signs »

What are causes of Kawasaki disease?

The cause is not known. Microorganisms and toxins like that of scarlet fever have been suspected, but none has been identified to date.

It is common for Kawasaki disease to occur after a preceding infection, such as tonsillitis, ear infection, pneumonia, urine infection, or gastrointestinal infection.
Genetic factors (genetic variants in some patients) and the immune system (for example, autoimmune disease) seem to play roles in the disease, which is characterized by immune activation.
The disease is more common in those of Japanese or Korean descent.

Who develops Kawasaki disease?

Kawasaki disease typically affects children under 5 years of age. Only rarely does it affect children over 8 years of age, in which case it is sometimes referred to as atypical Kawasaki disease.

What are the symptoms and signs of Kawasaki disease?

The usual symptoms and signs of Kawasaki disease include

prolonged fever (about 5 days),
reddening of the eyes without pus (pinkeye),
cracked and inflamed lips and mucous membranes of the mouth with an inflamed strawberry tongue,
ulcerative gum disease (gingivitis),
swollen lymph nodes in the neck (cervical lymphadenopathy),
joint pain often on both sides of the body,
irritability,
cough and runny nose, and
a rash that is raised and bright red, with cracking and peeling skin (desquamation), especially on the palms and soles.

The rash appears in a glove-and-sock fashion over the skin of the hands and feet. The rash becomes hard, swollen (edematous), and then peels off.

What are the unusual signs and symptoms of Kawasaki disease?

Most of the common symptoms described above will resolve without complications, even if untreated. Less common findings include

inflammation of the lining of the heart (pericarditis),
joints (arthritis), or
covering of the brain and spinal cord (meningitis), and
the other heart problems listed below in the section on serious complications.

The outlook (prognosis) for an individual affected is primarily determined by the seriousness of any heart complications.

QUESTION

The term arthritis refers to stiffness in the joints.
See Answer

What is the difference between Kawasaki disease and Kawasaki syndrome?

They are the same. Kawasaki disease is also referred to as Kawasaki syndrome. It was first described in the late 1960s in Japan by the renowned pediatrician Tomisaku Kawasaki.

Is Kawasaki disease contagious?

No. Kawasaki disease is not believed to be a contagious illness. However, Kawasaki disease symptoms
and signs often start after the patient has had an acute infection with something else. The cause of the preceding illness may be something contagious.

How can Kawasaki disease cause serious complications?

Children with Kawasaki disease can develop inflammation of the arteries of various parts of the body.

This inflammation of the arteries is called vasculitis. Arteries that can be affected include the arteries that supply blood to the heart muscle (the coronary arteries).
Vasculitis can cause weakening of the blood vessels and lead to areas of vessel widening (aneurysms).
The weakening occurs because of the destruction of the elastic tissue in the walls of the blood vessels.
Coronary artery aneurysms occur because of such injury to the blood vessels in Kawasaki disease.

Because of the potential for heart injury and coronary artery aneurysms, special tests are performed to examine the heart.

Children are typically evaluated with an electrocardiogram (EKG) and an ultrasound test of the heart (echocardiogram).
Monitoring for this problem is crucial throughout life as it can develop as a late aftereffect of Kawasaki disease.
Other arteries that can become inflamed include the arteries of the lungs, neck, and abdomen.
These effects can lead to breathing problems, headaches, and abdominal pain, respectively.
Blood tests to measure the degree of inflammation (such as C-reactive protein, or CRP, and erythrocyte sedimentation rate, or ESR) are often used to monitor the activity of the disease.

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What is the treatment for Kawasaki disease?

Children affected by Kawasaki disease are hospitalized.

Kawasaki disease is treated with high doses of aspirin (salicylic acid) to reduce inflammation and to mildly thin the blood to prevent blood clot formation. This is one of the few times when children may take aspirin.
Also used in treatment is gamma globulin administered through the vein (intravenous immunoglobulin or IVIG), together with fluids. This treatment has been shown to decrease the chance of developing coronary aneurysms in the coronary arteries, especially when used early in the illness.
Sometimes cortisone medications are given. Persisting joint pains are treated with anti-inflammatory drugs, such as ibuprofen (Advil) or naproxen (Aleve).
Plasma exchange (plasmapheresis) has been reported as effective in patients who were not responding to aspirin and gamma globulin. Plasmapheresis is a procedure whereby the patient's plasma is removed from the blood and replaced with protein-containing fluids. By taking out portions of the patient's plasma, the procedure also removes antibodies and proteins that are felt to be part of the immune reaction that is causing the inflammation of the disease.

Kawasaki disease that is not responding to the traditional cornerstones of treatment, aspirin and gamma globulin infusions, can be deadly. Treatments being investigated include doxycycline, statin drugs (Lipitor, Mevacor, others), anakinra (Kineret), and cyclosporine (Neoral).

What is the prognosis for children with Kawasaki disease?

Kawasaki disease is typically self-limited and generally resolves on its own after four to eight weeks, and with early treatment, full recovery is usual.

Rarely, Kawasaki disease can cause death from blood clots forming in abnormal areas of widening (aneurysms) of the heart arteries (coronary arteries) and myocarditis (inflammation of heart muscle). Aneurysms of the arteries to the heart (coronary arteries) can occur early or late, even when the children are adults so follow-up is recommended for those patients diagnosed with the disease. Those children with larger aneurysms have a worse prognosis because of this risk. Such aneurysms can lead to blood clots, heart attacks (myocardial infarction), and internal bleeding. Those whose echocardiograms do not demonstrate widening of the coronary arteries throughout life do best. Those with any signs of aneurysm changes require very close monitoring. Children less than 6 months of age and those with high levels of inflammation on blood testing are at highest risk.

The earlier the diagnosis is made and treatment is begun the better the outcome.

Researchers are searching for methods of detecting which children are at risk for the development of aneurysms of the coronary arteries. Further research is under way to investigate a variety of criteria for atypical variants of Kawasaki disease that do not have classical presentations.

Is it possible to prevent Kawasaki disease?

Because the cause of Kawasaki disease has not been determined, there are no measures known that can prevent the disease. Early evaluation and treatment can decrease the chance for long-term problems and/or complications.

Kawasaki disease and the new multisystem inflammatory syndrome in children (MIS-C)

Another disease recently noted to have almost identical signs and symptoms to Kawasaki disease has been linked to the COVID-19 (coronavirus) pandemic. The new disease seems more virulent than Kawasaki disease. The CDC named the disease (as of May 14, 2020) multisystem inflammatory syndrome in children or MIS-C. The following is the case definition for MIS-C provided by the CDC:

An individual under 21 years of age with fever, laboratory evidence of inflammation, and evidence of clinically severe illness requiring hospitalization with multisystem (>2) organ involvement (cardiac, renal, respiratory, hematologic, gastrointestinal, dermatologic or neurological);
and
no alternative plausible diagnoses; and
positive for current or recent SARS-CoV-2 infection by reverse-transcriptase polymerase chain reaction, serology,
or antigen test; or COVID-19 exposure within the 4 weeks prior to the onset of symptoms.

The CDC noted the fever should be at least 100.4 F (38 C) for at least 24
hours or a subjective fever lasting 24 hours. The main differences between MIS-C
and Kawasaki disease are a more rapid and serious advancement of symptoms,
especially fever and multisystem organ problems like cardiac and respiratory
problems along with a current or recent infection with SARS-CoV-2. Some children
suffer a rapid heartbeat and may develop cardiac and/or respiratory arrest.