serious reactions. Overall, life-threatening complications resulting from therapy for Kawasaki disease are exceedingly rare, especially compared with the risk of nontreatment. Evidence indicates Kawasaki disease produces altered lipid metabolism that persists beyond the clinical resolution of the disease. Rarely, recurrence can occur in Kawasaki disease with or without treatment. Epidemiology Kawasaki disease affects boys more than girls, with people of Asian ethnicity, particularly Japanese people. The higher incidence in Asian populations is thought to be linked to genetic susceptibility. Incidence rates vary between countries. Currently, Kawasaki disease is the most commonly diagnosed pediatric vasculitis in the world. By far, the highest incidence of Kawasaki disease occurs in Japan, with the most recent study placing the attack rate at 218.6 per 100,000 children less than five years of age (about one in 450 children). At this present attack rate, more than one in 150 children in Japan will develop Kawasaki disease during their lifetimes. However, its incidence in the United States is increasing. Kawasaki disease is predominantly a disease of young children, with 80% of patients younger than five years of age. 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 5 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,