2021 Update on the Clinical Management and Diagnosis of Kawasaki Disease.

Purpose of Review: Provide an updated review of the clinical management and diagnosis of Kawasaki disease with inclusion of potential diagnostic difficulties with multisystem inflammatory syndrome in children (MIS-C) given the ongoing COVID-19 pandemic. Recent Findings: Adjunctive corticosteroid therapy has been shown to reduce the rate of coronary artery dilation in children at high risk for IVIG resistance in multiple Japanese clinical studies (most notably RAISE study group). Additional adjunctive therapies (etanercept, infliximab, cyclosporin) may also provide limited benefit, but data is limited to single studies and subgroups of patients with cardiac abnormalities. The efficacy of other agents (atorvastatin, doxycycline) is currently being investigated. MIS-C is a clinically distinct entity from KD with broad clinical manifestations and multiorgan involvement (cardiac, GI, hematologic, dermatologic, respiratory, renal). MIS-C with Kawasaki manifestations is more commonly seen in children < 5 years of age. Summary: The 2017 American Heart Association (AHA) treatment guidelines have included changes in aspirin dosing (including both 80-100 mg/kg/day and 30-50 mg/kg/day treatment options), consideration of the use of adjuvant corticosteroid therapy in patients at high risk of IVIG resistance, and the change in steroid regimen for refractory KD to include both pulse-dose IVMP and longer course of prednisolone with an oral taper. A significant proportion of children diagnosed with MIS-C, a post-infectious syndrome of SARS-CoV-2 infection, meet criteria for Kawasaki disease. Further investigation is warranted to further delineate these conditions and optimize treatment of these conditions given the ongoing COVID-19 pandemic.