Kawasaki Disease

There is no single laboratory test that confirms Kawasaki disease. Instead, diagnosis is based on a set of established clinical criteria: a high fever lasting five days or more, combined with at least four of the characteristic features described above. Doctors also work to rule out other conditions that can cause similar symptoms, such as scarlet fever, measles, certain drug reactions, and other inflammatory conditions of childhood, since these require different treatment. The diagnostic workup typically includes:

• Blood tests to look for markers of inflammation and support the overall clinical picture, though they cannot diagnose the condition on their own
• Echocardiogram — an ultrasound of the heart performed to examine the coronary arteries for early signs of dilation or aneurysm, since coronary artery involvement is the central concern
• Electrocardiogram, which may be used to assess the heart's electrical activity

Even when initial heart imaging appears normal, treatment is typically started based on the clinical symptoms and blood work alone, since delaying treatment while awaiting further test results increases the risk of coronary damage.

The standard treatment for Kawasaki disease includes:

• Intravenous immunoglobulin — a blood product that helps calm the abnormal immune response
• High-dose aspirin — helps reduce inflammation and fever in the acute phase

When given within the first ten days of illness, this combination substantially lowers the risk of coronary artery aneurysms. After the fever resolves, children are typically continued on a lower, long-term dose of aspirin for several weeks to reduce the risk of blood clotting while the blood vessels heal. In children whose coronary arteries develop significant aneurysms, additional medications to prevent blood clot formation may be needed, and in rare, severe cases, further anti-inflammatory treatments may be used if the initial treatment does not fully control the inflammation. Because coronary artery damage is the primary concern, regardless of how mild the child's overall illness appeared, follow-up echocardiograms are performed at set intervals after diagnosis to track how the coronary arteries are healing.