What Is Kawasaki Disease?

Kawasaki disease is a childhood illness characterized by inflammation of blood vessels throughout the body. It primarily affects children under 5, though older children and adults can also develop the disease. While the exact cause is unknown, researchers believe a combination of genetic and environmental factors may contribute to the development of Kawasaki disease.

Symptoms of Kawasaki disease typically appear in distinct stages. Initially, a high fever lasting more than five days occurs along with symptoms such as bloodshot eyes, rash, swollen lymph nodes, and redness or swelling of the lips and tongue. In the second phase, children may have joint pain and gastrointestinal symptoms (e.g., vomiting, diarrhea).

For most children, symptoms gradually fade away within a few weeks. In some cases, Kawasaki disease can cause long-term heart problems. Prompt diagnosis and treatment can help prevent complications. 

Kawasaki disease occurs in approximately 4,200 children annually in the United States. Although it can be a serious condition, most children recover fully without lasting effects with proper medical care.

Kawasaki Disease Symptoms 

Kawasaki disease progresses in three distinct phases over several weeks. Symptoms can vary from child to child—some children with Kawasaki disease will experience every symptom, and some may only have only a few. Symptoms may come and go and can vary in severity.

Phase 1: Acute Phase Symptoms

The acute phase of Kawasaki disease lasts from one to two weeks. The initial and most prominent symptom is a persistent high fever (often above 102.2 degrees) lasting more than five days and is unresponsive to fever-reducing medications (e.g., acetaminophen, ibuprofen).

Other symptoms that may appear during phase 1 of Kawasaki disease include:

• Bloodshot eyes, usually without discharge 
• A red and blotchy rash on the trunk and genital area 
• Swollen lymph nodes
• Swollen skin on the palms of the hands and soles of the feet with a red/purple color 
• Dry, red, cracked lips 
• Swollen tongue with red bumps near the back of the tongue (strawberry tongue) 

Phase 2: Subacute Phase Symptoms

The second phase of Kawasaki disease typically begins about two weeks after the fever begins and lasts 2-3 weeks. Symptoms may include:

• Peeling skin on the fingertip and toes
• Joint pain
• Abdominal pain
• Vomiting 
• Diarrhea
  

Phase 3: Convalescent Phase Symptoms

Phase 3 of Kawasaki disease can last from a few weeks to months. Most children gradually recover during this phase as symptoms begin to subside. Some children may experience the following signs and symptoms:

• Horizontal ridges or dents in the fingernails (Beau’s lines) 
• Fatigue 
• Irritability 
  

What Causes Kawasaki Disease? 

With Kawasaki disease, medium-sized blood vessels throughout the body become inflamed (known as vasculitis). Researchers aren’t sure why this occurs, but it may be triggered by an abnormal immune response to certain infections (e.g., viral, bacterial). However, no specific virus or bacteria has been identified as the primary cause, and research suggests that genetic factors may increase the disease risk in some children.

Kawasaki disease is not contagious and cannot spread from person to person.

Risk Factors

Certain factors are linked to an increased risk of developing Kawasaki disease:

• Age: About 80% of Kawasaki disease cases occur in infants and children under age 5. 
• Sex: Boys are more likely to develop the disease than girls. 
• Ethnicity: Children of Asian descent, particularly Japanese and Korean ethnicity, have higher rates of Kawasaki disease.
• Genetics: Gene variants in the ITPKC gene, which plays a role in regulating immune system responses, have been linked to an increased risk of Kawasaki disease.
• Family history: Children whose parents have had Kawasaki disease have double the risk of developing the condition than those whose parents were unaffected.

Diagnosis

Healthcare providers diagnose Kawasaki disease based on a medical history review, a physical examination, and diagnostic tests. During the physical examination, your child’s healthcare provider will look for the characteristic symptoms of the disease, including fever, rash, bloodshot eyes, and swollen lymph nodes. 

To rule out other illnesses and confirm the diagnosis, healthcare providers order diagnostic tests that may include:

• Blood tests: These are used to measure iron levels, white blood cell count, and inflammation markers.  
• Urinalysis: A urine sample is examined to check for signs of infection. 
• Electrocardiogram (EKG): An EKG measures your heart’s electrical activity and can detect any abnormalities that may indicate Kawasaki disease is affecting your heart. 
• Echocardiogram (ECG): An imaging test that uses sound waves to create images of the heart and blood vessels. An ECG allows healthcare providers to identify any abnormalities or inflammation in your coronary arteries, which supply blood to your heart.

Treatments for Kawasaki Disease  

Once diagnosed with Kawasaki disease, children receive treatment in the hospital. Treatment should begin within the first 10 days of illness to lower the risk of heart complications. Treatment focuses on managing symptoms, reducing inflammation, and preventing long-term damage.

Kawasaki disease treatments include: 

• Intravenous immunoglobulin (IVIG): The cornerstone treatment of Kawasaki disease, IVIG involves the administration of a high dose of immunoglobulin intravenously (through a vein). IVIG helps decrease the risk of coronary artery problems.  
• Aspirin: High-dose aspirin is often given alongside IVIG in the acute phase of Kawasaki disease to help reduce fever and inflammation and prevent blood clots. After the acute phase, a lower dose of aspirin is typically continued for several weeks to prevent clot formation.
• Other medications: Additional medications may be prescribed in specific cases or if symptoms persist. These may include corticosteroids to reduce inflammation, antiplatelet drugs to prevent clotting, or other immunosuppressive drugs (medications used to reduce an overactive immune response). 
  

Complications 

With timely treatment, most children with Kawasaki disease recover without lasting complications. Left untreated, Kawasaki disease can lead to serious health complications, particularly related to the coronary arteries, which supply blood to the heart. 

Kawasaki disease complications include:

• Coronary artery aneurysms: These are bulging and weakened areas in the walls of the coronary arteries, which can develop due to inflammation. Aneurysms may lead to blood clot formation or restrict blood flow to the heart, increasing the risk of heart attack or internal bleeding. 
• Myocarditis: Inflammation of the heart muscle (myocardium) can occur, weakening heart function and potentially causing long-term heart problems.
• Heart rhythm and heart valve problems: Though rare, Kawasaki disease may cause inflammation and damage to heart valves or cause problems with regular heart rhythm.

Living With Kawasaki Disease

When diagnosed and treated promptly, most children with Kawasaki disease recover without lasting complications. The acute phase of the illness can be challenging for both children and their parents or caregivers. Providing emotional support and reassurance to your child can help them cope with the challenges of the disease. You may find it helpful to seek support from family, friends, and healthcare providers while their child is receiving treatment and recovering. 

Following your child’s treatment plan and attending regular follow-up appointments with healthcare providers is essential for helping your child recover. These appointments allow healthcare providers to monitor your child’s progress and address ongoing concerns. With appropriate care and support, children can lead normal, healthy lives following their recovery from Kawasaki disease.