What is Kawasaki disease?
Kawasaki disease is an inflammatory disease that primarily affects young children and infants. The cause is unknown. However, doctors don’t think it is contagious. Other names for the disease include Kawasaki syndrome and mucocutaneous lymph node syndrome.
Kawasaki disease causes widespread inflammation of blood vessels throughout the body. Symptoms include high fever, rash, swollen lymph nodes in the neck, and red or irritated eyes, lips, tongue and throat. Swelling of the hands and feet, along with peeling skin can also occur. Left untreated, Kawasaki disease can lead to problems with the heart and heart valves. In fact, it is the leading cause of acquired heart disease in American children.
Japan has the highest incidence of Kawasaki disease. A Japanese doctor, Tomisaku Kawasaki, was the first to describe the disease in 1967. In the United States, it is relatively rare. Around 5,000 children per year in this country are hospitalized with the disease. Up to 90% of these cases are in children younger than 5 years and older than 6 months. It most commonly affects boys of Asian or Pacific Island descent.
Early diagnosis and treatment spares most children from heart problems and long-term complications. The main Kawasaki disease treatment is IVIG (intravenous immunoglobulin). IVIG reduces the risk of coronary artery problems. Doctors may also use aspirin to treat inflammation and protect the heart. Other medicines are available for resistant cases.
The complications of Kawasaki disease are serious and can even be fatal in a small percent of children. Fortunately, most children recover fully when treatment is started within the first 10 days of the disease. Seek immediate medical care if your child displays any potential Kawasaki disease symptoms.
What are the symptoms of Kawasaki disease?
Kawasaki disease symptoms develop in three phases.
The main symptom of the first phase is a fever lasting at least five days. The fever is often high, reaching 102 degrees Fahrenheit or higher. Other common symptoms of this phase of Kawasaki disease include:
Dry, cracked, red, irritated lips and a red, swollen tongue with rough spots (‘strawberry tongue’)
Irritability or fussiness
Rash; Kawasaki disease rash affects the trunk of the body, but may also involve the arms and legs. It is typically worse in the diaper or genital area.
Sore or irritated throat
Swollen lymph nodes in the neck
Swollen hands and feet with red skin on the palms and soles
Phase one typically lasts 2 to 3 weeks and then the second phase begins. Common symptoms of phase two include:
Peeling skin on the hands and feet, especially on the fingers and toes. The skin may slough off in large sheets.
After phase two, symptoms slowly get better. This phase can be prolonged, taking up to eight weeks to fully resolve. During this time, children may lack energy and not act like themselves.
Symptoms that might indicate a serious or life-threatening condition
Kawasaki disease can lead to serious complications, including damage to the heart. In rare cases, it can be fatal. Seek immediate medical care (call 911) if your child has a fever for more than four days along with any four of the following symptoms:
Red or peeling skin on the palms or soles
Red, swollen, irritated lips, tongue, or lining of the mouth
Redness and irritation in both eyes
Swollen lymph glands in the neck
When children get treatment within the first 10 days of the disease, the risk of complications goes down significantly. However, Kawasaki disease can be difficult to diagnose. It may be necessary to consult specialists to get the right diagnosis. Doctors involved in diagnosing and treating Kawasaki disease include pediatric cardiologists, infectious disease doctors, and rheumatologists.
What causes Kawasaki disease?
Doctors and researchers do not know exactly what causes Kawasaki disease. Many experts think the cause is an abnormal immune system reaction. There are several theories about what could trigger the immune system. An infection is at the top of the list. However, scientists have not been able to identify a specific organism. The disease itself is not contagious, but it does tend to occur in clusters and is more common during the winter and spring. This suggests an infectious agent could play a role. There may also be a genetic predisposition to developing the disease.
What are the risk factors for Kawasaki disease?
There are a number of factors that increase the risk of developing Kawasaki disease. Any child can get the disease, but it is more likely in children with risk factors. Kawasaki disease risk factors include:
Age younger than 5 years
Asian or Pacific Islander ancestry
Reducing your risk of Kawasaki disease
Because the cause is unknown, it is nearly impossible to prevent Kawasaki disease. But you can help reduce the risk of complications by seeking treatment early. See your child’s doctor for fevers lasting more than four days or for symptoms of Kawasaki disease.
How is Kawasaki disease treated?
Because the risk of complications is high, hospitalization is almost always necessary. The goal of treatment is to reduce fever, inflammation, and the risk of complications. Starting treatment within 10 days of symptom onset offers the best chance of reaching this goal. This makes it very important to seek a diagnosis as soon as possible.
The main treatments for Kawasaki disease are IVIG (intravenous immunoglobulin) and high-dose aspirin. Immunoglobulin contains antibodies from blood donors. Research has shown these antibodies can reduce the risk of developing coronary artery problems. In children receiving aspirin alone, about 20% will end up with coronary artery problems. IVIG decreases this number to 3 to 4%.
In most cases, children will show improvement after one dose of IVIG. But some kids don’t. If this happens, doctors may recommend additional doses of IVIG. There are also other medicines that can help control inflammation. Options include corticosteroids, infliximab (Remicade), and etanercept (Enbrel).
Because of the risk of Reye’s syndrome, most people know not to give aspirin to children with a potential viral infection. Kawasaki disease is an exception because of aspirin’s beneficial role in protecting the heart. However, children should still only take aspirin under a doctor’s supervision. Should a viral infection occur, it may be necessary to stop aspirin therapy.
What are the potential complications of Kawasaki disease?
Most children fully recover from Kawasaki disease without complications. Early treatment increases the chances of a full and safe recovery. However, Kawasaki disease is the leading cause of acquired heart disease for children in the United States. Babies under 1 year of age have the highest risk of developing heart complications.
Heart problems can include:
Coronary artery problems, such as inflammation and aneurysm—a weakening and bulging of the artery wall. The coronary arteries supply blood to the heart muscle. An aneurysm in these vessels increases the risk of heart attack and life-threatening internal bleeding.
Heart valve problems
Inflammation and damage to the heart muscle
The risk of heart problems is highest in the first few weeks. But problems can show up months or years later. Doctors will continue to monitor children for heart problems for several weeks, months or years after the fever is gone. This usually involves periodic echocardiograms.