• 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, but is caused by problems with the immune system.

Between 1 percent and 4 percent¹ of the U.S. population — up to 13 million people — live with hidradenitis suppurativa, a skin condition characterized by painful bumps and sores in the skin.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 or apocrine acne,³ can negatively affect quality of life and often proves difficult to treat.⁴

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.⁵

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 1.⁶ 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.⁷ Depression and self-imposed isolation are common among people with HS, as pain and visible effects on the skin can take an emotional toll.⁸

What Causes Hidradenitis Suppurativa?

Blocked hair follicles cause the symptoms of HS, but researchers don’t yet know what prompts that to happen. Scientists believe the condition could be influenced by genetics, hormones, excess weight, or cigarette smoking.⁹

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 the parts of the skin containing apocrine sweat glands.¹⁰

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 neck¹¹ and the skin behind the ears can be affected by HS as well.¹²

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. ⁹

Symptoms of HS may include blackheads, as well as red and 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 years.⁹

Swollen lumps associated with HS may spontaneously rupture with a strong-smelling discharge, heal, and then recur. These lesions sometimes fuse into dermal abscesses, which may leak pus and can be hard to heal. Fistulas (abnormal connections between two organs or tissues) can also form, leading to the development of extensive tunnels under the skin known as sinus tracts.¹³

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.¹³

Some people with HS may also experience itching, burning, and profuse sweating.¹⁴

HS can impact quality of life by causing psychological symptoms, such as depression, anxiety, stress, low self-esteem, social isolation, and problems with intimacy.¹⁵

“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.⁶ One review of 39 studies on people with HS determined that African Americans have the highest risk of developing HS.¹⁶

Another study of 47,690 people with HS found that African-American women aged 40 and under have the highest risk of developing hidradenitis suppurativa in comparison to other ethnic and age groups in the U.S.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.¹⁰

Genetics play a role in the development of hidradenitis suppurativa. For people who have a biological parent with HS, the risk of inheriting the genes that can cause HS is 50 percent.¹⁷ However, not everyone with the genes will develop HS. And some people who don’t have any relatives with HS may still develop it.

HS more commonly affects those who smoke cigarettes, and people who are carrying excess 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. People with acne or with polycystic ovary syndrome (PCOS) may also be at greater risk for HS.¹⁰

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.

HS cannot be spread from one person to another.¹

“I don’t date anymore, because they all think this is contagious,” wrote one myHSteam member.

HS lesions often develop around the genitals and anus because these areas contain apocrine glands.¹

“The men I have dated think it is an STD and break off any relationship we had,” wrote a myHSteam member.

Dermatologists have determined that HS is not caused by poor hygiene.¹

“People just don’t understand, and their first reaction is that it's a hygiene issue,” wrote one myHSteam member. “However, I'm probably more hygienic than they are!”

According to the Centers for Disease Control and Prevention (CDC), a rare disease is one that affects fewer than 200,000 Americans.¹⁸ HS is not a rare disease, as it affects between 1 percent and 4 percent of the population, or up to 13 million Americans.¹

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).¹⁹

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)

Recurring lesions in multiple areas with limited scarring and sinus tracts characterize Hurley stage 2.

Hurley Stage 3 (Severe)

Multiple lesions, with more extensive sinus tract formations and scarring, are present in Hurley stage 3. During this stage, HS abscesses could cover the entire affected area.

Some doctors also use the modified Sartorius score, designed in 2003, 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.²⁰

Not all cases of hidradenitis suppurativa progress to more advanced stages, but some HS lesions can continue to reappear and grow more severe if not properly treated. Diagnosing and managing HS as early as possible is important to avoid progressing to a more severe stage.³

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.²¹

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.

In 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.²²

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, or by engaging with a support group, either in person or on 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

Some of the most common health conditions that occur along with HS include:²³

• Obesity — A risk factor for HS that can exacerbate symptoms
• Metabolic syndrome — A combination of high blood glucose, obesity, high cholesterol, and high blood pressure
• Diabetes — More likely in people with HS than people who don't have the skin condition
• Depression — Common in people with HS, as it is with most chronic health conditions
• Crohn’s disease and ulcerative colitis — Have been linked with HS
• Heart disease — May occur in those with HS
• Rheumatoid arthritis and psoriatic arthritis — Common in people with HS
• Skin cancer and other skin diseases — Especially skin conditions that cause open, noninfectious sores
• Spondyloarthritis — More common in people with HS than in the general population²⁴