The Evolving Role of Corticosteroids in Kawasaki Disease: Evidence, Mechanisms, and Clinical Implications.

Kawasaki disease (KD) is an acute pediatric vasculitis and remains the leading cause of acquired heart disease in children in developed countries. Although timely administration of intravenous immunoglobulin (IVIG) significantly reduces coronary complications, approximately 10-20% of patients are resistant to initial therapy and remain at increased risk for coronary artery abnormalities (CAA). Corticosteroids, previously avoided because of concerns regarding vascular healing, have re-emerged as an adjunctive anti-inflammatory strategy in selected patients. Over the past decade, randomized controlled trials and meta-analyses have clarified their role, particularly in high-risk populations. The RAISE trial demonstrated that early, multi-day prednisolone administered concomitantly with IVIG significantly reduced CAA incidence in high-risk children, whereas earlier single-pulse methylprednisolone regimens failed to show consistent benefit. The 2022 Cochrane review and subsequent observational studies from Asia and North America confirmed improved coronary outcomes without an increased risk of adverse events. Recent guidelines from the American Heart Association (2024) and the Japanese Circulation Society (2023) now recommend corticosteroids as part of initial therapy for patients at high risk of IVIG resistance. This review summarizes the evolving evidence, pathophysiologic rationale, and practical considerations regarding corticosteroid use in KD, highlighting their role as a risk-stratified adjunct to IVIG rather than universal first-line therapy.