Objective To explore the temporal, area, and population distribution characteristics of reported scarlet fever cases in Shanxi province from 2016 to 2025. And provide evidence for the development of area specific and precise prevention and control strategies.

Methods The incidence data of scarlet fever reported in Shanxi from 2016 to 2025 were collected for a descriptive analysis on the temporal, area, and population distributions of the cases by using Excel 2016. The comparisons of rates and trend were conducted by χ² test with IBM SPSS Statistics 26.0. Global (Moran's I) and local (local indicators of spatial association, LISA) spatial autocorrelation analyses were conducted with ArcGIS Pro 3.4.2.

Results From 2016 to 2025, a total of 19 622 scarlet fever cases were reported in Shanxi without death. The average annual incidence rate was 5.44/100 000, showing an upward trend (trend χ²=923.980, Z=30.397, P<0.001). The epidemic showed phased variations and a bimodal incidence peak pattern, which occur during May-June and during November-December. The cases were reported in all the 11 prefectures (municipality) in the province with the high average annual incidence rates being reported in Changzhi (10.13/100 000) and Taiyuan (9.26/100 000). In terms of the gender distribution, the incidence was significantly higher in men than in women (χ²=557.760, P<0.001). Children aged 0−10 years were the mostly affected group, with the highest incidence being observed in children aged 4-7 years. There were significant differences in incidence among different age groups (χ²=25 378.854, P<0.001). Most cases were preschool and school aged children, and the proportion of preschool aged children gradually increased (trend χ²=12.449, Z=3.529, P<0.001). Global spatial autocorrelation analysis revealed a positive spatial association in scarlet fever incidence in Shanxi from 2016 to 2025 (Moran's I=0.27, Z=4.098, P<0.001). A similar positive spatial autocorrelation was also found during 2016−2022 and during 2024−2025 (both Moran's I>0, P<0.05), indicating distinct spatial clustering. Local spatial autocorrelation analysis results suggested spatial heterogeneity in scarlet fever incidence. Generally, the southern area had higher incidence rate while the western area had lower incidence rate. The hot spot area showed a trend of shifting from the north to the south.

Conclusion From 2016 to 2025, the incidence of scarlet fever in Shanxi exhibited an overall increasing trend with clear seasonal, demographic, area and spatial distributions, suggesting that targeted preventive and control measures should be taken to effectively prevent the spread of the disease.