About 2,000–4,000 cases are identified in the U.S. each year (9 to 19 per 100,000 children younger than five years of age). In the continental United States, Kawasaki disease is more common during the winter and early spring, boys with the disease outnumber girls by ≈1.5–1.7:1, and 76% of affected children are less than years of age.In the United Kingdom, prior to 2000, it was diagnosed in fewer than one in every 25,000 people per year. Incidence of the disease doubled from 1991 to 2000, however, with four cases per 100,000 children in 1991 compared with a rise of eight cases per 100,000 in 2000. By 2017, this figure had risen to 12 in 100,000 people with 419 diagnosed cases of Kawasaki disease in the United Kingdom.In Japan, the rate is 240 in every 100,000 people.Coronary artery aneurysms due to Kawasaki disease are believed to account for 5% of acute coronary syndrome cases in adults under 40 years of age. History
The disease was first reported by Tomisaku Kawasaki in a four-year-old child with a rash and fever at the Red Cross Hospital in Tokyo in January 1961, and he later published a report on 50 similar cases. Later, Kawasaki and colleagues were persuaded of definite cardiac involvement when they studied and reported 23 cases, of which 11 (48%) patients had abnormalities detected by an electrocardiogram. In 1974, the first description of this disorder was published in the English-language literature. In 1976, Melish et al. described the same illness in 16 children in Hawaii.
Genetic factors are also thought to influence development of coronary artery aneurysms and response to treatment. The exact genetic contribution remains unknown. Genome-wide association studies and studies of individual candidate genes have together helped identify specific single nucleotide polymorphisms (SNPs), mostly found in genes with immune regulatory functions. The associated genes and their levels of expression appear to vary among different ethnic groups, both with Asian and non-Asian backgrounds.SNPs in FCGR2A, CASP3, BLK, ITPKC, CD40 and ORAI1 have all been linked to susceptibility, prognosis, and risk of developing coronary artery aneurysms. Various other possible susceptibility genes have been proposed, including polymorphisms in the HLA region, but their significance is disputed. Genetic susceptibility to Kawasaki disease appears complex. Gene–gene interactions also seem to affect susceptibility and prognosis. At an epigenetic level, altered DNA methylation has been proposed as an early mechanistic factor during the acute phase of the disease. Diagnosis
Since no specific laboratory test exists for Kawasaki disease, diagnosis must be based on clinical signs and symptoms, together with laboratory findings. Timely diagnosis requires careful history-taking and thorough physical examination. Establishing the diagnosis is difficult, especially early in the course of the illness, and frequently children are not diagnosed until they have seen several health-care providers. Many other serious illnesses can cause similar symptoms, and must be considered in the differential diagnosis, including scarlet fever, toxic shock syndrome, juvenile idiopathic arthritis, and childhood mercury poisoning (infantile acrodynia).Classically, five days of fever plus four of five diagnostic criteria must be met to establish the diagnosis.