What Is Kawasaki Disease?

A rare but serious illness

Kawasaki disease (KD), or mucocutaneous lymph node syndrome, is an illness that causes inflammation in arteries, veins, and capillaries.
It also affects your lymph nodes and causes symptoms in your nose, mouth, and throat. It’s the most common cause of heart disease in children.

Dr. Tomisaku Kawasaki

Tomisaku Kawasaki is a Japanese pediatrician who first described Kawasaki disease in 1967. Prior to his report, physicians did not recognize Kawasaki disease as a new diagnosis. Although Kawasaki disease was first described in Japan, the disease is found all over the world.

The Kawasaki Disease Foundation (KDF) estimates that KD affects more than 4,200 children in the United States each year. KD is also more common in boys than in girls and in children of Asian and Pacific Island descent. However, KD can affect children and teenagers of all racial and ethnic backgrounds.
In most cases, children will recover within a few days of treatment without any serious problems. Recurrences are uncommon. If left untreated, KD can lead to serious heart disease. Read on to learn more about KD and how to treat this condition.

Symptoms

What are the symptoms of Kawasaki disease?

Kawasaki disease occurs in stages with telltale symptoms and signs. The condition tends to appear during late winter and spring. In some Asian countries, cases of KD peak during the middle of summer.

Early stages

Early symptoms, which can last up to two weeks, may include:

• high fever that persists for five or more days
• rash on the torso and groin
• bloodshot eyes, without crusting
• bright red, swollen lips
• “strawberry” tongue, which appears shiny and bright with red spots
• swollen lymph nodes
• swollen hands and feet
• red palms and soles of the feet

Heart problems may also appear during this time.

Late stages

Later symptoms begin within two weeks of the fever. The skin on the hands and feet of your child may start to peel and come off in sheets. Some children may also develop temporary arthritis, or joint pain.
Other signs and symptoms include:

• abdominal pain
• vomiting
• diarrhea
• enlarged gallbladder
• temporary hearing loss

Call your doctor if your child is showing any of these symptoms. Children who are younger than 1 or older than 5 are more likely to present incomplete symptoms. These children make up the 25 percent of KD cases that are at a heightened risk of experiencing heart disease complications.

Causes and risk factors

What causes Kawasaki disease?

The exact cause of Kawasaki disease is still unknown. Researchers speculate that a mixture of genetics and environmental factors can cause KD. This may be due to the fact that KD occurs during specific seasons and tends to affect children of Asian descent.

Risk factors

Kawasaki disease is most common in children, particularly those of Asian descent. About 75 percent of KD cases are children under the age of 5, according to the KDF. Researchers don’t believe that you can inherit the disease, but the risk factors tend to increase within families. Siblings of someone who has KD are 10 times more likely to have the disease.

How is Kawasaki disease diagnosed?

There is no specific test for Kawasaki disease. A pediatrician will take into account the child’s symptoms and rule out illnesses with similar symptoms, such as:

• scarlet fever, a bacterial infection that causes fever, chills, and sore throat
• juvenile rheumatoid arthritis, a chronic disease that causes joint pain and inflammation
• measles
• toxic shock syndrome
• idiopathic juvenile arthritis
• juvenile mercury poisoning
• medical reaction
• Rocky Mountain spotted fever, a tick-borne illness

A pediatrician might order additional tests to check how the disease has affected the heart. These may include:

• Echocardiograph: An echocardiograph is a painless procedure that uses sound waves to create pictures of the heart and its arteries. This test may need to be repeated to show how Kawasaki disease has affected the heart over time.
• Blood tests: Blood tests may be ordered to rule out other illnesses. In KD, there may be an elevated white blood cell count, low red blood cell count, and inflammation.
• Chest X-ray: A chest X-ray creates black and white images of the heart and lungs. A doctor may order this test to look for signs of heart failure and inflammation.
• Electrocardiogram: An electrocardiogram, or ECG, records the electrical activity of the heart. Irregularities in the ECG may indicate that the heart has been affected by KD.

Kawasaki disease should be considered a possibility in any infant or child who has a fever lasting more than five days. This is especially the case if they’re showing other classic symptoms of the disease like peeling skin.

Treatment

How is Kawasaki disease treated?

Children diagnosed with KD should begin treatment immediately to prevent heart damage.
First-line treatment for KD involves an infusion of antibodies (intravenous immunoglobulin) over 12 hours within 10 days of the fever and a daily dosage of aspirin over the next four days. The child may need to continue to take lower doses of aspirin for six to eight weeks after the fever goes away to prevent the formation of blood clots.

One study also found that the addition of prednisolone significantly reduced potential heart damage. But this has yet to be tested in other populations.
Timing is critical for preventing serious heart problems. Studies also report a higher rate of resistance to treatment when it’s given before the fifth day of the fever. About 11 to 23 percent of children with KD will have a resistance.

Some children may require longer treatment time to prevent a blocked artery or a heart attack. In these cases, treatment involves daily antiplatelet aspirin doses until they have a normal echocardiograph. It may take six to eight weeks for coronary artery abnormalities to reverse.

Complications

What are the possible complications of Kawasaki disease?

KD leads to serious heart problems in about 25 percent of the children who have the disease. Untreated KD can lead increase your risk for a heart attack and cause:

• myocarditis, or inflammation of the heart muscle
• dysrhythmia, or an abnormal heart rhythm
• aneurysm, or weakening and bulging of the artery wall

Treatment for this stage of the condition requires long-term dosing of aspirin. Patients may also need to take blood thinners or undergo procedures such as coronary angioplasty, coronary artery stenting, or coronary artery bypass. Children who develop coronary artery problems due to KD should take care to avoid lifestyle factors that can increase their risk for a heart attack. These factors include being obese or over weight, having high cholesterol, and smoking.

What’s the long-term outlook for Kawasaki disease?

There are four possible outcomes for someone with KD:

• You make a full recovery without heart problems, which requires early diagnosis and treatment.
• You develop coronary artery problems. In 60 percent of these cases, patients are able to reduce these concerns within a year.
• You experience long-term heart problems, which requires long-term treatment.
• You have a reoccurrence of KD, which happens in only 3 percent of cases.

KD has a positive outcome when diagnosed and treated early. With treatment, only 3 to 5 percent of KD cases develop with coronary artery problems. Aneurysms develop in 1 percent.
Children who have had Kawasaki disease should receive an echocardiogram every one or two years to screen for heart problems.

Takeaway

The takeaway

KD is a disease that causes inflammation in your body, mainly the blood vessels and lymph nodes. It mainly affects children under the age of 5, but anyone can contract KD.
The symptoms are similar to a fever, but they show up in two distinct stages. A persistent, high fever that lasts for more than five days, a strawberry tongue, and swollen hands and feet are a few of the symptoms of the early stage. In the later stage, symptoms may include joint paint, skin peeling, and abdominal pain.

Talk to your doctor if your child shows any of these symptoms. In some children, the symptoms may appear incomplete, but KD can cause serious heart problems, if left untreated. About 25 percent of the cases that do develop into heart disease are due to misdiagnosis and delayed treatment.
There’s no specific diagnostic test for KD. Your doctor will look at your children’s symptoms and preform tests to rule out other conditions. Timely treatment can significantly improve the outcome for children with KD