Because children with Kawasaki disease will be taking aspirin for up to several months, vaccination against varicella and influenza is required, as these infections are most likely to cause Reye syndrome.High-dose aspirin is associated with anemia and does not confer benefit to disease outcomes.About 15-20% of children following the initial IVIG infusion show persistent or recurrent fever and are classified as IVIG-resistant. While the use of TNF alpha blockers (TNF-α) may reduce treatment resistance and the infusion reaction after treatment initiation, further research is needed. Due to the potential involvement of the upregulated calcium-nuclear factor of activated T cells pathway in the development of the disease, a 2019 study found that the combination of ciclosporin and IVIG infusion can suppress coronary artery abnormalities. Further research is needed to determine which patients would respond best to this treatment.Corticosteroids have also been used,  especially when other treatments fail or symptoms recur, but in a randomized controlled trial, the addition of corticosteroid to immune globulin and aspirin did not improve outcome. Additionally, corticosteroid use in the setting of Kawasaki disease is associated with increased risk of coronary artery aneurysm, so its use is generally contraindicated in this setting. In cases of Kawasaki disease refractory to IVIG, cyclophosphamide and plasma exchange have been investigated as possible treatments, with variable outcomes.
The highest rate of progression to stenosis occurs among those who develop large aneurysms. The worst prognosis occurs in children with giant aneurysms. This severe outcome may require further treatment such as percutaneous transluminal angioplasty, coronary artery stenting, bypass grafting, and even cardiac transplantation.A relapse of symptoms may occur soon after initial treatment with IVIG. This usually requires rehospitalization and retreatment. Treatment with IVIG can cause allergic and nonallergic acute reactions, aseptic meningitis, fluid overload, and rarely, other 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.