The novel coronavirus disease 2019 (COVID-19) caused by severe acute respiratory 
syndrome coronavirus 2 (SARS-CoV-2) infection has been spreading worldwide since 
December 2019. Hundreds of cases of children and adolescents with Kawasaki 
disease (KD)-like hyperinflammatory illness have been reported in Europe and the 
United States during the peak of the COVID-19 pandemic with or without shock and 
cardiac dysfunction. These patients tested positive for the polymerase chain 
reaction or antibody test for SARS-CoV-2 or had a history of recent exposure to 
COVID-19. Clinicians managing such patients coined new terms for this new 
illness, such as COVID-19-associated hyperinflammatory response syndrome, 
pediatric inflammatory multisystem syndrome temporally associated with COVID-19, 
or COVID-19-associated multisystem inflammatory syndrome in children (MIS-C). 
The pathogenesis of MIS-C is unclear; however, it appears similar to that of 
cytokine storm syndrome. MIS-C shows clinical features similar to KD, but 
differences between them exist with respect to age, sex, and racial 
distributions and proportions of patients with shock or cardiac dysfunction. 
Recommended treatments for MIS-C include intravenous immunoglobulin, 
corticosteroids, and inotropic or vasopressor support. For refractory patients, 
monoclonal antibody to interleukin-6 receptor (tocilizumab), interleukin-1 
receptor antagonist (anakinra), or monoclonal antibody to tumor necrosis factor 
(infliximab) may be recommended. Patients with coronary aneurysms require 
aspirin or anticoagulant therapy. The prognosis of MIS-C seemed favorable 
without sequelae in most patients despite a reported mortality rate of 
approximately 1.5%.