Facts and Figures



  • The global prevalence rate of hidradenitis suppurativa (HS) is estimated to about 1%.1
  • However, because the condition is often misdiagnosed and many people living with HS don’t always feel comfortable talking about their symptoms or seeking out their dermatologist for help, the number of people who are actually diagnosed with HS is far less than this estimate.2,3,4
  • HS commonly occurs in young adults in their early 20s, but can occur at any age; prevalence usually reduces after the age of 50 to 55.5,6
  • Women are more likely to develop HS than men.5,6


  • HS is a chronic skin condition characterized by inflamed areas typically located around the armpits and groin. These inflamed areas often include painful lesions, nodules and boils, and usually occur where certain sweat glands (known as apocrine glands) are located, as well as under the breasts, on the buttocks and in the inner thighs, where skin rubs together.5,6,7,8,9,10


  • With apocrine glands (sweat glands in areas with abundant hair follicles) such as the armpits and groin.5,6,8,9
  • Where skin rubs together, such as under the breasts, the buttocks, the inner thighs.6,8,9


  • Though the exact causes of HS are unclear, research suggests that the root of HS lies in specific defects within hair follicles.6,11
  • Other recent research has hypothesized that inflamed lesions associated with HS tends to develop when there is a blockage of hair follicles and inflammation of sweat glands in the apocrine family, which are found in areas such as the armpits and groin.6,7,8
  • Is it thought that this blockage can occur when sweat becomes trapped inside sweat gland tubes, which eventually swell up and either burst or become severely inflamed.12

When is it time to talk to a dermatologist?

  • If you or someone you know is experiencing recurring, painful nodules or boils in the armpits or groin area, it is important to see a dermatologist to ensure proper diagnosis and care. Visit our Talking to Your Dermatologist section for information and tips to help guide a discussion with a health care provider.


  1. Revuz J. Hidradenitis suppurativa. J Eur Acad Dermatol Venereol 2009;23:985–998.
  2. Esmann S, Jemec GB. Psychosocial impact of hidradenitis suppurativa: a qualitative study. Acta Derm Venereol 2011;91:328–332.
  3. Jemec GB, Heidenheim M, Nielsen NH. The prevalence of hidradenitis suppurativa and its potential precursor lesions. J Am Acad Dermatol 1996;35:191–194.
  4. Dufour ND, Emtestam L, Jemec GB. Hidradenitis suppurativa: a common and burdensome, yet under-recognised, inflammatory skin disease. Postgrad Med J 2014;90:216–221.
  5. Jemec GB. Clinical practice. Hidradenitis suppurativa. N Engl J Med 2012;366:158–164.
  6. Zouboulis CC, Tsatsou F. Disorders of the apocrine sweat glands. In: Goldsmith LA, Katz SI, Gilchrest BA, Paller AS, Leffell DJ, Wolff K. Fitzpatrick’s Dermatology in General Medicine. 8th ed. New York, Chicago: McGraw Hill; 2012. p947–959.
  7. Collier F, Smith R, Morton C. Diagnosis and management of hidradenitis suppurativa. BMJ 2013;346:f2121.
  8. Mayo Clinic. Hidradenitis Suppurativa. Available at: http://www.mayoclinic.com/health/hidradenitis-suppurativa/DS00818. Accessed August 2013.
  9. Kurzen H, Kurokawa I, Jemec GB, et al. What causes hidradenitis suppurativa? Exp Dermatol 2008;17:455–456; discussion 457–472.
  10. Fimmel S, Zouboulis CC. Comorbidities of hidradenitis suppurativa (acne inversa). Dermatoendocrinol 2010;2:9–16.
  11. Danby FW, Jemec GB, Marsch WCh, von Laffert M. Preliminary findings suggest hidradenitis suppurativa may be due to defective follicular support. Br J Dermatol 2013;168:1034–1039.
  12. The British Association of Dermatologists. Hidradenitis Suppurativa. Available at: http://www.bad.org.uk/for-the-public/patient-information-leaflets/hidradenitis-suppurativa. Accessed May 2015.