• Hidradenitis suppurativa (HS) is a skin disease that causes painful, recurring bumps that may leak fluid and scar when they heal.
• Early diagnosis and treatment can benefit people with HS, but diagnosis is often delayed by years.
• HS is not contagious or caused by poor hygiene. It is caused by problems with the immune system.

Between 1 percent and 4 percent of the U.S. population — up to 13 million people — live with hidradenitis suppurativa, a chronic skin condition characterized by painful lesions on the skin.^1,2 HS lesions may last for months, heal and recur repeatedly, form scars, or burst and leak pus with a strong odor. HS, also known as acne inversa, can negatively affect quality of life and be difficult to treat.³

Hidradenitis suppurativa is often mistaken for other skin conditions, including acne, boils, cysts, and folliculitis. HS forms when the hair follicles clog due to cell overgrowth.¹ Because HS can look like other common skin conditions, it is best to see a dermatologist for diagnosis.⁴

HS can occur at any age, but it often develops when people are in their early 20s. It is more common in women than in men by a ratio of about 3 to 1.² Early diagnosis and treatment can help manage HS symptoms, prevent progression, and avoid complications such as scarring.

Unfortunately, there is often a significant delay in diagnosis. One study found the average time from the start of symptoms until a diagnosis of HS was 10 years. Depression and self-imposed isolation are common among people with HS, as pain and visible effects on the skin can take an emotional toll.⁵

What Causes Hidradenitis Suppurativa?

Blocked hair follicles cause the symptoms of HS, but researchers don’t yet know what prompts that to happen and haven’t identified the exact cause of HS. Scientists are researching whether the condition could be influenced by genetics or hormones.¹

Where Does HS Occur?

Skin contains two types of sweat glands. Eccrine sweat glands release fluid onto the surface of the skin, and apocrine sweat glands release fluid into the hair follicles. HS occurs on areas of the body containing apocrine sweat glands.⁶

Areas with apocrine sweat glands include:

• The underarms
• The groin
• Under the breasts
• Between the buttocks
• The perineum (skin around the anus)

In some people, the nape of the neck and the skin behind the ears can be affected by HS as well.^7,8

What Are the Symptoms of HS?

The disease usually starts with one painful bump that remains for weeks or months. Some people only experience mild symptoms, but for others, HS gets progressively worse.⁶

Symptoms of HS may include blackheads, as well as tender bumps or lesions that may grow larger. Hard, pea-sized lumps often mistaken for boils can also develop under the skin and persist for months.⁹

Swollen lumps associated with HS may spontaneously rupture with a strong-smelling discharge, heal, and then return. These lesions sometimes develop into abscesses, which may leak pus and can be hard to heal. Extensive tunnels under the skin, known as sinus tracts, may also form.⁶

Sinus tracts can become linked under the skin’s surface, causing inflammation and allowing infection to travel deeper and become more widespread. In severe cases, thick, painful scar tissue can form and may limit movement in affected areas.⁶

Some people with HS may also experience itching, burning, and profuse sweating.¹⁰

HS can impact quality of life by causing psychological symptoms, such as depression, anxiety, stress, low self-esteem, social isolation, and problems with intimacy.¹¹

“I’m having several flare-ups today, and I’m just extremely depressed — whenever this happens, all I do is sleep,” said one myHSteam member. Another wrote, “Stressed and wondering how I will ever hold a stable relationship when all I can think about are these scars and new flares on my body.”

Who Is at Risk for Hidradenitis Suppurativa?

Hidradenitis suppurativa affects between 1 percent and 4 percent of the U.S. population.¹ HS is more than three times as common in women as in men.² One review of 39 studies on people with HS determined that African Americans have the highest risk of developing HS.¹²

Another study of 47,690 people with HS found that women, people who are African American or biracial, and people between the ages of 30 and 39 have the highest risks for HS.¹³

HS usually begins around puberty when hormone levels rise and activate the apocrine sweat glands. Few people develop HS before puberty begins, and severe HS symptoms after menopause are rare.⁶

Genetics may play a role in the development of hidradenitis suppurativa, but not everyone with a family history of hidradenitis suppurativa will develop HS. In addition, some people who don’t have any relatives with HS may still develop it.¹⁴

HS more commonly affects those who smoke cigarettes, and people who have a higher body weight. Though they are not considered direct causes of HS, smoking and obesity are risk factors that may increase the chance of developing HS and make symptoms more severe. Your doctor may advise you to quit smoking or provide weight loss advice to help manage your condition. People with acne or with polycystic ovary syndrome (PCOS) may also be at greater risk for HS.⁶

Common Misconceptions About HS

There are many misconceptions about hidradenitis suppurativa that contribute to the stigma around this painful and sometimes debilitating condition. Here are the facts.

What Are the Stages of HS?

Dermatologists use a system known as Hurley stages to describe cases of hidradenitis suppurativa from mild (stage 1) to severe (stage 3).¹⁶

• Hurley Stage 1 (Mild)
  HS in Hurley stage 1 is a single lesion or several abscesses without sinus tract formation or scarring.

• Hurley Stage 2 (Moderate)
  Hurley stage 2 is characterized by recurring lesions in multiple areas with limited scarring and sinus tracts.

• Hurley Stage 3 (Severe)
  Multiple lesions, with more extensive sinus tract formations and scarring, are present in Hurley stage 3. During this stage of severe hidradenitis suppurativa, HS abscesses could cover the entire affected area.

Some doctors also use a modified Sartorius score to describe HS symptoms. This score is based on which parts of the body are involved, the number and type of HS lesions, and the distance between lesions.¹⁷

Not all cases of hidradenitis suppurativa progress to more advanced stages, but some HS lesions can continue to reappear and worsen if not properly treated. Diagnosing and managing HS as early as possible is important to avoid progressing to a more severe stage.

What Are the Treatment Options for HS?

There is currently no permanent cure for hidradenitis suppurativa, although it may become inactive for long periods after successful treatment.

Medications, which may include antibiotics, corticosteroids, hormonal treatments, and biologics, can improve symptoms for some people with HS.⁹ Some medications for HS are taken orally, while others are applied topically or injected. Antibiotics can reduce inflammation, fight infection, prevent HS from worsening, and stop new breakouts. Corticosteroids can also help reduce inflammation, which can help clear HS and prevent new breakouts. Talk to your health care provider if you think medication might be the right choice for you, and ask about potential side effects or medication interactions.

For some people, HS proves difficult to treat and does not respond to medications. Surgery can be effective in treating people who have had advanced HS symptoms for some time. Surgery is sometimes successful in rendering HS inactive over long periods, though lesions may recur in other areas of skin.¹⁸

Many people with HS experience anxiety, depression, and social isolation related to HS symptoms. Psychological symptoms of HS may improve with talk therapy, cognitive behavioral therapy, or meditation. It can be helpful to engage with a support group in person or online, such as myHSteam.

“Finding this community has made an amazing impact on my mental health,” one myHSteam member wrote. “It’s great to know I’m not alone in this battle — everyone is so supportive and has great advice.”

It is just as important for people with HS and depression to seek treatment for their psychological symptoms as it is to treat their skin symptoms. If you are feeling depressed, talk with your doctor about treatment and a potential referral to a mental health specialist.

Health Conditions Associated With HS

People with HS may be more likely to develop certain other health conditions as well. These include¹⁹:

• Diabetes — This health condition is more likely in people with HS.
• Crohn’s disease and ulcerative colitis — Inflammatory bowel diseases have been associated with HS.
• Obesity — This risk factor for HS can also exacerbate symptoms.
• Heart disease — Cardiovascular conditions are sometimes present alongside HS.
• Metabolic syndrome — This syndrome is a combination of high blood glucose, obesity, high cholesterol, and high blood pressure that can influence HS.
• Rheumatoid arthritis and psoriatic arthritis — These types of arthritis are more common for people with HS.
• Depression — Experiencing depression is common with many chronic health conditions, including HS.
• Skin cancer and other skin diseases — Other skin conditions that cause open, noninfectious sores can also influence HS.
• Spondyloarthritis — This type of arthritis, usually located in the spine and hips, is more common for people with HS than the general population.²⁰