Abstract
Background/Objectives: This aim of this study was to describe the demographic, clinical, and laboratory characteristics of hospitalized children with benign acute childhood myositis (BACM) and to evaluate seasonal patterns, including changes observed during the COVID-19 pandemic. Methods: We conducted a retrospective single-center review of pediatric patients hospitalized with a diagnosis of BACM between January 2016 and December 2024. Clinical, laboratory, and epidemiological data were analyzed, including seasonal distribution before and after the COVID-19 pandemic. Results: We identified 47 cases of BACM, with a male predominance (66%) and a median age of 7 years. Most cases (72%) occurred during autumn and spring. The most common prodromal symptoms were fever, cough and rhinorrhea. Bilateral calf pain was the most frequent presenting symptom. The median creatine phosphokinase (CPK) level was 4986 U/L, with higher values in boys (p = 0.040). Higher CPK levels were associated with longer hospital stays in our cohort (p = 0.030). Influenza B was the most frequently identified pathogen (63%). No BACM cases were recorded during the COVID-19 pandemic period (2020-2022), followed by an increase in 2024. All patients fully recovered, with a median hospital stay of 3.2 days. Conclusions: BACM is a self-limiting condition with a characteristic clinical and laboratory profile. The absence of cases during the COVID-19 pandemic suggests a possible association between reduced viral circulation and BACM incidence. Awareness of its typical presentation may support early diagnosis, reduce unnecessary investigations, and facilitate appropriate clinical management.