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Hidradenitis suppurativa: Causes

What causes hidradenitis suppurativa?

The cause of this disease is still a bit of a mystery. Based on what scientists have learned so far, we know that hidradenitis suppurativa (HS) begins in hair follicles. These are tiny structures in our skin from which hair grows.

Here’s what scientists believe happens inside a hair follicle when HS develops:

  1. The hair follicle becomes clogged with keratin (a protein found in our skin, hair, and nails).

  2. As keratin and sweat (which can no longer flow out of the clogged hair follicle) build up, bacteria breed inside the hair follicle.

  3. When a hair follicle has more keratin, sweat, and bacteria than it can hold, the hair follicle bursts. This causes what looks like a deep, painful pimple (nodule) or painful and swollen lump filled with pus (abscess).

  4. The material that pours out of the ruptured hair follicle spreads to nearby hair follicles.

  5. As more hair follicles become clogged, more lumps form.

  6. After the skin heals, it scars. Years of flare-ups can cause thick scars that limit how much you can move.

  7. Without treatment, hair follicles may continue to clog and burst open. This can cause tunnels to form deep in the skin. Some people develop serious infections.

In the United States, young women who are African American or biracial are most likely to get hidradenitis suppurativa (HS).

Mother comforting daughter who has painful hidradenitis suppurativa

Is HS an autoimmune disease?

While studying HS, researchers have found some evidence that HS might be an autoimmune disease. People with HS develop antibodies. This finding alone doesn’t mean that HS is an autoimmune disease.

The body naturally releases antibodies to destroy bacteria, viruses, and other invaders that shouldn’t be inside the body.

When someone has an autoimmune disease, antibodies mistakenly attack a part of the body. For example, a person develops rheumatoid arthritis when the body attacks its own joints.

To know whether HS is an autoimmune disease, more research is needed to find out why the body is producing antibodies.

Who gets HS?

Some people have a greater risk of developing HS. Here’s what researchers have found can increase your risk of developing HS:

Blood relative with HS: This disease can run in families. Many people who develop HS have a family member with this disease.

While having a blood relative with HS may increase your risk, it’s important to keep in mind that many people who develop this disease do not have a blood relative with HS.

Exposure to a trigger: To get HS, it seems that something must trigger it. Scientists believe that cigarette smoking is the most common trigger for HS. Researchers have found that between 70% and 90% of people who get HS smoke cigarettes.

Being overweight also seems to trigger HS. The more overweight you are, the higher your risk of developing HS and of having severe HS.

What triggers HS for one person may not trigger it for another.

Gender: Females get HS more often than males. It’s still not clear why this happens.

Hormones may play a role. This could explain why HS can flare before you get your period. It would also help explain why HS can be less severe during pregnancy and after menopause begins.

Age: Most people develop HS between puberty and before 40 years of age. It’s very rare for HS to begin before puberty.

Race: In the United States, African Americans, Hispanics, and people who are biracial develop HS more often than white people.

Studies find that African Americans tend to have more severe HS. African Americans who have HS also tend to have a greater risk of developing a type of skin cancer called squamous cell carcinoma. This skin cancer can develop where you’ve had HS for many years.

Psoriasis: If you have psoriasis, a condition that causes scaly patches on the skin, you have a higher risk of developing HS.

While what causes HS is still a mystery, these findings have given us a better understanding of what causes HS and also led to better ways to treat this condition. Today, treatment often requires a multi-pronged approach that includes medication, skin care, and self-care.

Find out how dermatologists treat HS at, Hidradenitis suppurativa: Treatment.

Getty Images

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Bowers J. “Tailor-made care.” Dermatol World. 2020;30(7);114-9.

Fernandez JM, Hendricks AJ, et al. “Menses, pregnancy, delivery, and menopause in hidradenitis suppurativa: a patient survey.” Intl J Women’s Dermatol. 2020: [epub ahead of print]. DOI: 10.1016/j.ijwd.2020.07.002.

Goldberg SR, Strober BE, et al. “Hidradenitis suppurativa: Current and emerging treatments.” J Am Acad Dermatol. 2020;82(5):1061-82.

Lee EY, Alhusayen R, et al. “What is hidradenitis suppurativa?” Can Fam Physician. 2017;63(2):114-20.

Lyons AB, Shabeeb N, et al. “Emerging medical treatments for hidradenitis suppurativa.” J Am Acad Dermatol 2020;83:554-62.

Narla S, Price KN, et al. “Proceeding report of the fourth Symposium on Hidradenitis Suppurativa Advances (SHSA) 2019.” J Am Acad Dermatol (2020: [epub ahead of print] doi:10.1016/ j.jaad.2020.05.114.

Ravn Jørgensen A-H, Brøgger-Mikkelsen M, et al. “Patients with a familial predisposition to hidradenitis suppurativa have a distinct clinical phenotype.” J Am Acad Dermatol 2020: [epub ahead of print] doi: 10.1016/j.jaad.2020.04.022.

Shetty PN. Araoye E, et al. “Prevalence of autoimmune disease in patients with hidradenitis suppurativa seen in ambulatory settings from 2008 to 2017.” Plastic and Reconstructive Surgery - Global Open: 2020;8(9S):82-3.

Tracey EH. “Don't forget these 5 things when treating hidradenitis suppurativa.” Cutis. 2019 Nov;104(5):E27-8.

Written by:
Paula Ludmann, MS

Reviewed by:
Shani Francis, MD, MBA, FAAD
Elena Hawryluk, MD, PhD, FAAD
William Warren Kwan, MD, FAAD

Last updated: 5/3/22