There is no test for Kawasaki Disease, which is diagnosed from the presence of the various symptoms, including the failure to respond to antibiotics and the persistence of high fever for more than 5 days.

Treatment of this disease proceeds in two stages:

Stage One - the Acute Phase. The patient is given aspirin and intravenous immunoglobulin. These medications can prevent the formation of aneurysms on the coronary arteries, especially if administered during the first 10 days of the illness. If small aneurysms form they may resolve over time.

Most children experience a full recovery after Kawasaki Disease has run its course. However, new research shows that Kawasaki patients may be prone to the development of coronary artery abnormalities in later life. Therefore it is recommended that these patients get follow up once every five years.

Stage Two - the treatment of coronary aneurysms. Those patients who develop coronary aneurysms will require regular monitoring by echocardiography and sometimes by coronary angiography and should continue taking aspirin. If the coronary aneurysm is large, other anticoagulation medications (e.g. clopidogrel, warfarin) are usually added.

If coronary stenosis develops, bypass surgery or catheter intervention, usually a rotation ablation, may become necessary. However, new coronary aneurysms may develop after balloon angioplasty if coronary arterial dissection occurred due to excessive dilatation (usually due to the use of a high-pressure balloon). Thus, if coronary dissection was confirmed by intravascular ultrasound imaging, coronary stent implantation may be indicated for prevention of new aneurysm formation.

In cases of serious coronary lesions, there is a risk of myocardial infarction (heart attack). Therefore, it is important to monitor these patients at least yearly for the development of adverse symptoms.