The impact of inappropriate steroid exposure before the diagnosis of Kawasaki disease

Background: Kawasaki disease (KD) is a systemic inflammatory disease characterized by vasculitis. In South Korea, some pediatric doctors empirically prescribe steroids to control febrile pediatric patients. This study aimed to evaluate the clinical characteristics of patients with KD after steroid exposure.

Methods: This was a single-center, retrospective, observational study. This study included patients (aged ≤15 years) between January 2020 and July 2022. We compared two groups, one group exposed to steroids and the other group who were not, using the Student's t-test or analysis of variance; otherwise, the Mann-Whitney U test or Kruskal-Wallis test was conducted. Statistical significance was set at p < 0.05.

Results: In total, 190 patients with KD were enrolled; of these, 64 (33.7 %) had a history of steroid exposure, and 126 (66.3 %) had no history of steroid exposure. In the steroid exposure group, prolonged fever duration (6.72 ± 1.72 versus 5.61 ± 1.19, p-value = <0.001), a lower proportion of complete KD (29.69 % vs. 88.10 %, p-value = <0.001), and a significantly lower level of C-reactive protein were observed. However, no significant correlations were observed between the Transthoracic Echocardiography (TTE) results (coronary artery aneurysm, existence of pericardial effusion) and prognostic factors (days of hospitalization, the number of intravenous immunoglobulin administrations, and Kobayashi score) between the two groups.

Conclusions: Patients with KD and previous steroid exposure may exhibit an incomplete KD phenotype with prolonged fever. Although previous steroid exposure does not affect the prognosis of KD, including coronary artery aneurysms, it may mask the classic features of KD, resulting in a delayed diagnosis.