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  • Hidradenitis suppurativa is a chronic and debilitating inflammatory disorder of the hair follicles that localizes to intertriginous and anogenital regions of the body.

  • Lesions are characterized by inflammatory nodules, subcutaneous abscesses, and sinus tracts.

  • Reproductive-age women are disproportionately affected.

  • Hyperkeratotic plugging of the terminal hair follicle is a consistent histologic finding of early disease and is thought to be the primary pathophysiologic event.

Hidradenitis suppurativa (HS), otherwise known as acne inversa, is a multifactorial, chronic inflammatory disorder of the hair follicles in intertriginous and anogenital regions of the body. HS is characterized by recurrent, deep-seated, painful, subcutaneous nodules, sinus tracts, and hypertrophic scarring. The long-term sequelae, including chronic pain, skin contractures, and disfigurement, can detrimentally impact activities of daily living, social functioning, and psychosocial well-being.1,2


Robust epidemiologic data on HS is lacking. The reported point prevalence of HS worldwide is between 0.00033% and 4.1%.3 As of this writing, only 1 population-based incidence study has been published.4 Among residents of Olmsted County, Minnesota (population 144,000 in 2010), the overall annual age- and sex-adjusted incidence rate of HS was 6 per 100,000 person-years over a 40-year period.4 Between 1970 and 2008, the age- and sex-adjusted incidence rate rose steadily from 4.3 per 100,000 person-years to 9.6 per 100,000 person-years.4 The etiology of this trend is unclear but may be related to concomitant rises in risk factors among the general population, including obesity and metabolic syndrome, as well as improved physician recognition of HS.5

For unknown reasons, women are disproportionately affected (female-to-male ratio is 3.3:1) and more likely to develop axillary and genitofemoral lesions.4 Men, on the other hand, tend to develop perineal and perianal disease.4 Among women, the impact of menstruation, menopause, and pregnancy on the natural history of HS is inconsistent and warrants further study. Although unconfirmed by population-based studies, data suggests that black patients may be disproportionately affected by HS.6-9


HS is a chronic relapsing and remitting disease with an unpredictable clinical course, leading to detrimental impacts on quality of life. Lesions may begin as tenderness or pruritus that progresses to a tender papule or deep-rooted nodule (Fig. 84-1). Nodules can become quite large and painful. They may resolve slowly without drainage or progress to an abscess-like lesion that eventually ruptures and drains purulent material before involuting (Fig. 84-2). Involution may take 7 to 10 days,10 but in some patients, healing may be delayed, resulting in persistent open wounds with variable amounts of granulation tissue (Fig. 84-3). The process then reoccurs in adjacent and/or other intertriginous sites. With repeated episodes, epithelial strands may develop from ruptured follicular epithelium,11 leading to sinus tract formation and intermittent drainage of foul-smelling serosanguinous and/or purulent material (Fig. 84-4...

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