[Prevalence of hidradenitis suppurativa in Denmark]

The morbidity of hidradenitis suppurativa can be considerable, but little is known about its epidemiology. Our purpose was to describe the one-year and point prevalences of hidradenitis suppurative and its potential precursor lesions. We obtained the histories and examined an unselected sample (599 persons) of the general population (one-year prevalence), and we performed physical examination for a consecutive sample of 507 persons undergoing screening for sexually transmitted diseases (point prevalence). The point prevalence was 4.1% (95% confidence interval [CI] = 3.0-6.0) on the basis of objective findings. The one-year prevalence of hidradenitis was 1.0% (CI = 0.4-2.2) on the basis of subject recollection only. The patients in the sample on which the point prevalence is based were younger than those in the unselected sample of the general population (p < 0.001). Hidradenitis was significantly more common in women (p = 0.037), which may result from a female preponderance of genitofemoral lesions (odds ratio [OR] = 5.4; CI = 1.5-19.3). No sex difference was found in the prevalence of axillary lesions. Hidradenitis suppurativa is significantly more common than hitherto estimated. A female preponderance of patients is confirmed, except for patients with axillary lesions. Additional longitudinal studies are necessary to assess the importance of potential precursor lesions such as non-inflamed nodules or comedones.