There are no population-based incidence studies of hidradenitis suppurativa (HS). Using the medical records linkage system of the Rochester Epidemiology Project, we sought to determine incidence, as well as other associations and characteristics, for HS patients diagnosed in Olmsted County, Minnesota between 1968 and 2008. Incidence was estimated using the decennial census data for the county. Logistic regression models were fit to evaluate associations between patient characteristics and disease severity. A total of 268 incident cases were identified, with an overall annual age- and sex-adjusted incidence of 6.0 per 100,000. Age-adjusted incidence was significantly higher in women compared to men [8.2 (95% CI, 7.0–9.3) vs. 3.8 (95% CI, 3.0–4.7)]. The highest incidence was among young women aged 20–29 (18.4 per 100,000). The incidence has risen over the past four decades, particularly among women. Women were more likely to have axillary and upper anterior torso involvement, while men were more likely to have perineal or perianal disease. Additionally, 54.9% (140/255) patients were obese; 70.2% were current or former smokers; 42.9% carried a diagnosis of depression; 36.2% carried a diagnosis of acne; and 6% had pilonidal disease. Smoking and gender were significantly associated with more severe disease.

Background: Hidradenitis suppurativa (HS) is a follicular occlusion disorder occurring in apocrine-rich regions of the skin. Estimates of the prevalence of this disorder have not been population-based. Objective: We sought to provide population-based information on the prevalence of HS in Olmsted County, Minnesota, as of January 1, 2009. Methods: The Rochester Epidemiology Project, a unique infrastructure that combines and makes accessible all medical records in Olmsted County since the 1960s, was used to collect population-based data on the prevalence of HS. Results: We identified 178 confirmed cases of HS that included 135 females and 43 males, and estimated the total sex- and age-adjusted prevalence in Olmsted County to be 127.8 per 100,000 or 0.13%. The total prevalence was significantly higher among women than men. Conclusion: This study represents the first population-based investigation on the prevalence of HS. In this population-based cohort, HS was less prevalent than suggested by previous reports.