There's no specific test available to diagnose Kawasaki disease. Diagnosis largely is a process of ruling out diseases that cause similar signs and symptoms, including:
- Scarlet fever, which is caused by streptococcal bacteria and results in fever, rash, chills and sore throat
- Juvenile rheumatoid arthritis
- Stevens-Johnson syndrome, a disorder of the mucous membranes
- Toxic shock syndrome
- Certain tick-borne illnesses, such as Rocky Mountain spotted fever
The doctor will do a physical examination and have your child take other tests to help in the diagnosis. These tests may include:
- Urine tests. These tests help rule out other diseases.
Blood tests. Besides helping to rule out other diseases, blood tests look at white blood cell count, which is likely to be elevated, and the presence of anemia and inflammation, indications of Kawasaki disease.
Testing for a substance called B-type natriuretic peptide (BNP) that's released when the heart is under stress may be helpful in diagnosing Kawasaki disease earlier, recent research found. But, more research is needed to confirm this finding.
- Electrocardiogram. This test uses electrodes attached to the skin to measure the electrical impulses of your child's heartbeat. Kawasaki disease can cause heart rhythm complications.
- Echocardiogram. This test uses ultrasound images to show how well the heart is functioning and can help identify coronary artery abnormalities, if present.
To reduce the risk of complications, your child's doctor will want to begin treatment for Kawasaki disease as soon as possible after the appearance of signs and symptoms, preferably while your child still has a fever. The goals of initial treatment are to lower fever and inflammation and prevent heart damage.
To accomplish those goals, your child's doctor may recommend:
- Gamma globulin. Infusion of an immune protein (gamma globulin) through a vein (intravenously) can lower the risk of coronary artery problems.
- Aspirin. High doses of aspirin may help treat inflammation. Aspirin can also decrease pain and joint inflammation, as well as reduce the fever. Kawasaki treatment is a rare exception to the rule against aspirin use in children but only when given under the supervision of your child's doctor.
Because of the risk of serious complications, initial treatment for Kawasaki disease usually is given in a hospital.
After the initial treatment
Once the fever goes down, your child may need to take low-dose aspirin for at least six weeks and longer if he or she develops a coronary artery aneurysm. Aspirin helps prevent clotting.
However, if your child develops flu or chickenpox during treatment, he or she may need to stop taking aspirin. Taking aspirin has been linked to Reye's syndrome, a rare but potentially life-threatening condition that can affect the blood, liver and brain of children and teenagers after a viral infection.
Without treatment, Kawasaki disease lasts an average of 12 days, though heart complications may be evident later and be longer lasting. With treatment, your child may start to improve soon after the first gamma globulin treatment.
Monitoring heart problems
If your child has any indication of heart problems, the doctor may recommend follow-up tests to monitor heart health at regular intervals, often at six to eight weeks after the illness began, and then again after six months.
If your child develops continuing heart problems, the doctor may refer you to a doctor who specializes in treating heart disease in children (pediatric cardiologist). In some cases, a child with a coronary artery aneurysm may require:
- Anticoagulant drugs. These medications — such as aspirin, clopidogrel (Plavix), warfarin (Coumadin, Jantoven) and heparin — help prevent clots from forming.
- Coronary artery angioplasty. This procedure opens arteries that have narrowed to the point that they impede blood flow to the heart.
- Stent placement. This procedure involves implanting a device in the clogged artery to help prop it open and decrease the chance of another blockage. Stent placement may accompany angioplasty.
- Coronary artery bypass graft. This operation involves rerouting the blood around a diseased coronary artery by grafting a section of blood vessel from the leg, chest or arm to use as the alternate route.
Wait to vaccinate
If your child had treatment with gamma globulin, it's a good idea to wait at least 11 months to get the chickenpox or measles vaccine, because gamma globulin can affect how well these vaccinations work.
Coping and support
Find out all you can about Kawasaki disease so that you can make informed choices with your child's health care team about treatment options. Keep in mind that most children with Kawasaki disease recover completely, though it may be a little while before your child is back to normal and not feeling so tired and irritable. The Kawasaki Disease Foundation offers trained support volunteers to families currently dealing with the disease.
Preparing for your appointment
You'll probably first see your family doctor or pediatrician. However, in some cases your child may also be referred to a doctor who specializes in treating children with heart conditions (pediatric cardiologist).
Because appointments can be brief and there's often a lot to discuss, it's a good idea to be well-prepared. Here's some information to help you get ready for your appointment, as well as what you can expect from your child's doctor.
What you can do
- Write down any signs and symptoms your child is experiencing, including any that may seem unrelated. Try to keep track of how high your child's fever has been and how long it has lasted.
- Make a list of any medications, vitamins or supplements that your child is taking.
- Ask a family member or friend to join you, if possible. Sometimes it can be difficult to remember all of the information provided to you during an appointment. Someone who accompanies you may remember something that you missed or forgot.
- Write down questions to ask your doctor.
Your time with your doctor may be limited, so preparing a list of questions will help you make the most of your appointment. For Kawasaki disease, some basic questions to ask your child's doctor include:
- What's the most likely cause of my child's signs and symptoms?
- Are there any other possible causes for his or her signs and symptoms?
- Does my child need any tests?
- How long will the signs and symptoms last?
- What treatments are available, and which do you recommend?
- What are the possible side effects of the treatments?
- Are there any steps I can take to make my child more comfortable?
- What signs or symptoms should I watch for that might indicate that he or she is getting worse?
- What's my child's long-term prognosis?
- Are there any brochures or other printed material that I can take home with me? What websites do you recommend visiting?
In addition to the questions that you've prepared to ask your doctor, don't hesitate to ask any additional questions that may come up during your appointment.
What to expect from your doctor
Your child's doctor is likely to ask you a number of questions. Being ready to answer them may reserve time to go over any points you want to spend more time on. Your child's doctor may ask:
- When did your child begin experiencing symptoms?
- How severe are the signs and symptoms? How high has your child's fever been? How long did it last?
- What, if anything, seems to improve the symptoms?
- What, if anything, appears to worsen the symptoms?
- Has your child been exposed to any infectious diseases?
- Has your child been taking any medications?
- Does your child have any allergies?
What you can do in the meantime
Initially, you can give your child acetaminophen (Tylenol, others) or ibuprofen (Advil, Children's Motrin, others) to reduce the fever and make him or her more comfortable. However, treating your child's fever can make it difficult to accurately measure how severe the fever is and the actual duration of the fever.
Additionally, don't give your child aspirin without consulting the doctor first. In children and teenagers, taking aspirin during certain viral infections, such as chickenpox, has been associated with the development of Reye's syndrome — a rare but potentially life-threatening disorder. Kawasaki treatment is a rare exception to the rule against aspirin use in children but only when given under the supervision of your child's doctor.