Bacillus Calmette-Guerin scar reactivation (BCGitis) in Kawasaki disease. A Scoping Review

Aim: To map and synthesise the evidence on the scattered and heterogeneous reported prevalence of Bacillus Calmette_Guerin scar reactivation (BCGitis) in Kawasaki disease (KD), examine clinical associations, and identify knowledge gaps for future research. Methods: A scoping review was conducted in accordance with PRISMA-ScR guidelines. PubMed, Scopus, EMBASE, Web of Science, and Cochrane Library were searched for observational studies of BCG-vaccinated children with KD. We retrieved the prevalence of BCGitis and its associations with age, sex, KD form, BCG vaccine strain, coronary artery abnormalities (CAA), and treatment response. Results: Fifteen studies from five Asian countries (Japan, Korea, Taiwan, China, Singapore), including 21,880 children with KD, were identified. The reported prevalence of BCGitis ranged from 3.5% to 75.2% (overall prevalence 40.1%, 95% CI 39.6, 40.6), with a higher prevalence in younger children. It was associated with lower CAA rates (11.8% vs 13.8%) but showed no significant association with KD type, vaccine strain, or treatment response. Conclusion: BCGitis is a common manifestation of KD in BCG-vaccinated children and may have diagnostic and prognostic value, particularly in younger children and those with incomplete presentations.