Overview

Kawasaki disease is a rare but serious illness that primarily affects children under the age of 5. It causes inflammation in blood vessels throughout the body, especially the coronary arteries that supply blood to the heart. If left untreated, it can lead to long-term heart complications, including aneurysms.

The disease is named after Dr. Tomisaku Kawasaki, a Japanese pediatrician who first described it in 1967 after observing a pattern of symptoms in children, including persistent fever and distinctive skin and mouth changes. His discovery helped doctors recognize and treat this condition worldwide.

Although Kawasaki disease is not contagious, it tends to occur in clusters and is more common in winter and early spring. With prompt treatment—usually involving intravenous immunoglobulin (IVIG) and aspirin—most children recover fully within weeks.

Prevalence

• Kawasaki disease affects approximately 9 to 20 per 100,000 children under age 5 in the U.S.
• In 2019, over 5,000 children were hospitalized with Kawasaki disease, with 3,693 cases in children under 5, resulting in a hospitalization rate of 18.9 per 100,000 in that age group.
• Boys are about 1.5 times more likely than girls to develop the disease.
• Despite being rare, it is the leading cause of acquired heart disease in children in the United States.

Symptoms

Kawasaki disease typically begins with a high fever lasting at least 5 days, which does not respond well to usual fever-reducing medications. Other hallmark symptoms may include:

• Red, bloodshot eyes (without discharge)
• Cracked, red lips and a “strawberry” tongue
• Rash on the trunk or limbs
• Swelling and redness of the hands and feet, often followed by peeling skin
• Swollen lymph node in the neck (usually one-sided)

Additional symptoms can include irritability, joint pain, abdominal discomfort, vomiting, or diarrhea.

Not all children show every symptom, which can make diagnosis challenging. Some may have incomplete Kawasaki disease, with fewer than four classic signs but still face serious heart risks.

When to Seek Emergency Care

Immediate medical attention is crucial if a child has:

• A fever lasting 5 or more days
• Any combination of the symptoms listed above
• Signs of chest pain, rapid heartbeat, or difficulty breathing
• Extreme irritability or unusual sleepiness
• Trouble drinking fluids due to mouth pain or swelling

Early treatment, ideally within 10 days of symptom onset, can significantly reduce the risk of heart complications.

Causes

The exact cause of Kawasaki disease remains unknown. However, researchers believe it may be triggered by an abnormal immune response to an infection or environmental factor in genetically susceptible children.

Key points:

• No specific virus or bacteria has been confirmed as the cause.
• It is not contagious, children do not spread it like a cold or flu.
• Genetic factors may play a role, especially in children of Asian or Pacific Islander descent, who are at higher risk even when living outside of Asia.

Risk Factors

While Kawasaki disease can affect any child, certain factors increase the risk:

• Age: Most common in children under 5, with an average age around 2.
• Sex: Boys are more frequently affected than girls.
• Ethnicity: Children of Asian or Pacific Islander heritage are at higher risk.
• Extreme irritability or unusual sleepiness
• Family history: Having a sibling who had Kawasaki disease raises the likelihood for others in the family.

Despite these patterns, any child can develop Kawasaki disease. That’s why persistent fever and a cluster of symptoms should never be ignored.

Diagnosis

Kawasaki disease has no single definitive test, so doctors diagnose it by evaluating a child’s symptoms and medical history. The hallmark is a high fever lasting 5 or more days, combined with a pattern of specific symptoms. These include:

• Red, bloodshot eyes (without discharge)
• Changes in the mouth (cracked lips, red tongue)
• Rash on the body
• Swelling or redness of the hands and feet
• Enlarged lymph node in the neck

When multiple symptoms appear together, Kawasaki disease becomes a strong possibility.

To confirm the diagnosis and check for heart complications, doctors may order:

• Blood tests to check for inflammation, anemia, and elevated white blood cell count
• Urine tests to rule out other infections
• Echocardiogram to evaluate the coronary arteries and detect any abnormalities
• Electrocardiogram (ECG) to check heart rhythm

In cases where not all classic symptoms are presen (incomplete Kawasaki disease) these tests become even more critical to avoid missing the diagnosis.

Because the heart can be affected early, many children are referred to a pediatric cardiologist for immediate evaluation and follow-up.

Treatment

Treatment for Kawasaki disease is most effective when started within the first 10 days of illness. Children are typically admitted to the hospital for close monitoring and care.

Main Treatments

• Intravenous Immunoglobulin (IVIG): A solution of antibodies given through a vein to calm the immune system and reduce blood vessel inflammation. IVIG is most effective when administered within the first 10 days of illness.
• Aspirin: Initially given in high doses to reduce fever and inflammation, then lowered to a maintenance dose to prevent blood clots. Most children continue low-dose aspirin for 6–8 weeks, or longer if heart abnormalities are detected.

Why Timing Matters

Without treatment, about 25% of children may develop heart artery complications. With timely IVIG therapy, that risk drops to less than 5%.

Children typically continue low-dose aspirin for 6 to 8 weeks, or longer if heart issues are detected.

Prevention

Currently, there is no known way to prevent Kawasaki disease, as its exact cause remains unclear. Unlike many childhood illnesses, there is no vaccine or specific preventive measure available.

What Parents Can Do

• Early recognition is key. If a child has a fever lasting more than 5 days, especially with signs like red eyes, rash, or swollen hands and feet, they should be evaluated by a doctor immediately.
• Prompt treatment significantly reduces the risk of heart complications and improves outcomes.

While Kawasaki disease itself cannot be prevented, early action and close follow-up are the best ways to protect a child’s heart and overall health.