Scabies increasing incidence in Bologna from 2013 to 2024: a retrospective analysis

Objectives: Scabies infestation, caused by the Sarcoptes scabiei mite, has recently emerged as a public health concern in Western nations, with increased incidence worldwide. In Bologna, Italy, local health authorities report a rise in scabies diagnoses, although detailed data are limited. This study aimed to analyse the temporal trends of scabies cases diagnosed at S. Orsola Hospital's Dermatological Emergency Department, focusing on significant changes in incidence and seasonal variation over time. Methods: A retrospective observational study was conducted using data from October 2013 to September 2024, extracted from hospital records using ICD-9 (International Classification of Diseases, Ninth Revision) codes. Variables included monthly case counts, discharge date, patient age and nationality. All pruritic cases from the emergency department were evaluated in the dermatology unit, with diagnosis confirmed via dermoscopic or microscopic examination. Only first visits were included, excluding follow-up visits or post-therapy controls to avoid duplication. Monthly cases were aggregated to identify annual and seasonal trends. χ2 tests assessed nationality distribution differences, and linear regression analysed annual trends. Seasonal variation was evaluated with the Kruskal-Wallis test. Results: A total of 1192 cases were diagnosed. The nationality distribution remained stable, with no significant differences between Italian-born and other nationalities. A significant upward trend in incidence was observed in recent years, with seasonal variation showing higher case counts in February, March and April, and the lowest in July and August. Conclusions: The increase in scabies cases in recent years and distinct seasonal peaks suggests that environmental and social factors may contribute to transmission in Bologna. Without demographic changes and known drug resistance, factors such as the rise in tourism and suboptimal accommodation conditions may play a role in transmission. Enhanced public health monitoring, awareness and targeted interventions are recommended to manage this trend effectively.