In general, Kawasaki disease can be diagnosed within 5 days of fever by a combination of clinical manifestations, cardiac ultrasound, electrocardiogram, blood test, etc., while blood test alone is only an auxiliary examination and cannot be used as a diagnostic criterion. Kawasaki disease is an acute febrile rash pediatric disease with systemic vasculitis as the main lesion, which often occurs in infants and young children under 5 years of age, and is more common in males than females. It initially presents with hyperthermia, i.e., a body temperature higher than 39°C, and the duration of fever is usually more than 5 days. Usually within 5 days of fever, there will be bleeding from the mucous membranes of the mouth and pharynx, as well as bilateral conjunctival congestion without exudate in the eyes, localized rashes, swollen lymph nodes in the neck, as well as dry lips and mouth, accompanied by prune tongue, etc. It is recommended to go to the hospital in time for the relevant examination, and its blood routine can be manifested as elevated white blood cell counts, platelet increase, increased C-reactive protein, and accelerated sedimentation, etc. The cause of Kawasaki disease is still not known. The cause of Kawasaki disease is still unknown, once discovered, it is recommended to take active treatment in time, the prognosis is generally good, and some of them can recover on their own. The prognosis is generally good, and some of them can recover on their own. If the disease is not diagnosed and treated in time, it can lead to coronary aneurysm and other diseases in serious cases.