Facts and Figures



  • The global prevalence rate of hidradenitis suppurativa is estimated to be about 1%.However, because the skin condition is often misdiagnosed and many people living with HS don’t always feel comfortable talking about their symptoms or seeking out a dermatologist for help, the number of people who are actually diagnosed with HS is far less than this estimate.2,3
  • 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 55.2,3
  • Women are more likely to develop HS than men. 2,3


  • Hidradenitis suppurativa, also known as 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 sweat glands) are located, as well as under the breasts, on the buttocks and in the inner thighs, where skin rubs together.2,3,4,5,6,7


  • Hidradenitis suppurativa typically affects areas on the body:

    • With apocrine sweat glands (sweat glands in areas with abundant hair follicles) such as the armpits and groin.2,3,5,6
    • Where skin rubs together, such as under the breasts, the buttocks, the inner thigh. 3,5,6


  • Though the exact causes of hidradenitis suppurativa are unclear, research suggests that the root of HS lies in specific defects within hair follicles.3,8
  • Other recent research has hypothesized that inflamed skin lesions associated with HS tend to develop when there is a blockage of hair follicles and inflammation of apocrine sweat glands, which are found in areas such as the armpits and groin.,3,4,5
  • Is it thought that this blockage can occur when sweat becomes trapped inside apocrine sweat gland tubes, which eventually swell up and either burst or become severely inflamed.9

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. JEADV 2009, 23, 985 –998
  2. Jemec G.  Hidradenitis Suppurativa. N Engl J Med. 2012; 366:158-64.
  3. Zouboulis CC, Tsatsou F (2012) Disorders of the apocrine sweat glands. In: Goldsmith LA, Katz SI, Gilchrest BA, Paller AS, Leffell DJ, Wolff K (eds) Fitzpatrick’s Dermatology in General Medicine. 8th ed, McGraw Hill, New York Chicago, pp 947-959.
  4. Collier F., Smith R., Morton C. Diagnosis and management of hidradenitis suppurativa. BMJ. 2013; 346:f2121.
  5. Mayo Health Clinic. Hidradenitis Suppurativa. Available at: http://www.mayoclinic.com/health/hidradenitis-suppurativa/DS00818.  Accessed August 2013.
  6. Kurzen H, Kurokawa I, Jemec GB, et al. What causes hidradenitis suppurativa? Exp Dermatol 2008; 17:455-6; discussion 7-72.
  7. Fimmel S, Zouboulis CC. Comorbidities of hidradenitis suppurativa (acne inversa). Dermatoendocrinol 2010; 2:9-16.
  8. Danby FW, et al. Preliminary findings suggest hidradenitis suppurativa may be due to defective follicular support. BJD. 2013; 168; 1034–1039.
  9. The British Association of Dermatologists. Hidradenitis Suppurativa. Available at:http://www.bad.org.uk/site/825/default.aspx. Accessed August 2013.