The clinical significance of erythema of BCG inoculation site in Kawasaki Disease

Background: Erythema and induration of the Bacillus Calmette-Guerin (BCG) inoculation site has been recognised as a significant sign in aiding diagnosing Kawasaki disease (KD). The study aims to evaluate the clinical significance of BCG site erythema.
Methods: A retrospective observational study of patients discharged with a diagnosis of KD from 01.01.2018 to 31.12.2018 was conducted. The proportion of patients with BCG site erythema was identified in either complete or incomplete KD and were statistically analysed in terms of age, race, gender and coronary artery outcomes. Multiple logistic regression model was used to identify if BCG site erythema was significantly correlated with any of the other clinical signs of KD.

Results: Of the 27 patients identified during the study period, 2 were excluded as their BCG inoculation site status was unknown with 1 of patient presented with myocardial infarction suspected of past KD in view of dilated coronary artery aneurysms with thrombosis. Ten patients (40%) had BCG site erythema, and all were below 30 months of age (p=0.015). Statistically, BCG erythema was not significant in terms of race, gender or coronary outcomes but the presence of BCG erythema in complete KD was significant (p= 0.046). There is significant correlation between BCG site erythema and erythema of extremities (p=0.004), and perianal erythema (p=0.014).
Conclusion: BCG site erythema is common in children below 30 months of age. It is significantly correlated with erythema of extremities and perianal erythema, and should be considered a diagnostic clinical sign in diagnosing KD.