Regional Variations in the Incidence of Lichen Sclerosus in Sweden: Insights from a Nationwide Register Study (2001-2021).

: Lichen Sclerosus (LSc) is a chronic inflammatory skin condition predominantly affecting the anogenital regions, with a well-recognised potential for malignancy. This study examines the incidence, demographic characteristics, and regional distribution of LSc in Sweden over a 20-year period. The analysis is based on data from the Swedish National Patient Register (NPR), with a focus on cases diagnosed in specialist care settings. A nationwide register-based study was conducted using data from the NPR, identifying cases of LSc diagnosed between 1 January 2001 and 1 January 2021. Data analysis explored incidence by region, sex, age, and diagnostic care setting. A total of 154,424 patients with LSc were included, and the control group consisted of the general Swedish population without known LSc. : The mean annual incidence of LSc was 0.81 per 1000 individuals across Sweden, with higher rates in females (1.14 per 1000) compared to males (0.47 per 1000). Incidence varied significantly across regions, with Blekinge, Kalmar, and Gotland exhibiting the highest rates. This study analysed the distribution of LSc diagnoses across medical specialties, finding that 29.8% of cases were managed by dermatology and venereology, while 17.2% were handled by gynaecology and obstetrics. The analysis of marital status revealed that the proportion of married and divorced LSc patients was significantly lower than the national averages for men and women. : This study highlights significant regional variations in LSc incidence. Future research should investigate whether environmental factors, genetic predisposition, socioeconomic disparities, or variations in healthcare access contribute to the variations in incidence. Such insights could lead to more targeted public health strategies for managing LSc across different regions.