Hidradenitis suppurativa (HS) is a chronic (long-term) condition that causes painful, recurring lesions to develop under your skin. There is currently no cure for HS, and it remains difficult to treat.

HS is not contagious, cannot be spread through sexual contact, and it is not caused by poor hygiene or infection. Instead, it is thought to be influenced by a combination of genetic, immune, and environmental factors.

In this article, you’ll learn more about the causes, symptoms, and treatments for HS, as well as tips for managing the condition. Working closely with a knowledgeable health care provider, such as a dermatologist (skin specialist), can help you find an effective approach to managing symptoms and improving your quality of life.

What Is Hidradenitis Suppurativa?

Hidradenitis suppurativa, also known as acne inversa, is a chronic skin condition that causes painful lumps to form under the skin. These lumps, or lesions, commonly develop where skin rubs together, such as in the groin, armpits, under the breasts, and on the buttocks. However, HS can appear in other areas, including the ears, back, neck, or face.

In some cases, lesions can cover large areas of the body, and tunnels (sinus tracts) can form underneath the skin, linking clusters of lumps. HS lesions may rupture, release pus with an unpleasant smell, and leave scars. The lesions may be referred to as lumps, nodules, boils, or abscesses, the latter being filled with pus.

HS primarily develops in areas of the body with a high number of apocrine sweat glands. The body has two types of sweat glands — eccrine and apocrine. Eccrine glands, found all over the body, release sweat directly onto the skin’s surface. This helps to regulate body temperature. Apocrine glands, on the other hand, are located in areas with many hair follicles, such as the armpits, groin, and around the nipples. These glands release sweat into the hair follicles rather than directly onto the skin.

Because HS lesions can resemble other skin conditions, such as acne, boils, cysts, or folliculitis (inflammation of the hair follicles), it is sometimes misdiagnosed. A correct diagnosis is important for effective treatment.

What Causes Hidradenitis Suppurativa?

The exact cause of HS isn’t fully understood. Researchers believe it may occur when hair follicles become blocked by an excess of keratin, a skin protein. This blockage can trigger inflammation and rupture in the hair follicles, leading to HS lesions. Hormones, genetics, and environmental factors are also thought to contribute to the development of HS. It has been linked to autoimmune disorders.

A family history of HS is a significant risk factor. About 1 in 3 people with HS have a close relative who also has the condition.

HS typically develops after puberty. Scientists think the timing of onset is related to the body’s changing levels of sex hormones during puberty. Likely for the same reasons, HS rarely develops after menopause.

HS is neither contagious or infectious. You cannot spread HS to others, and it cannot be “caught” from someone with the condition. However, HS lesions can sometimes develop secondary skin infections. These infections are separate from HS itself and may be transmissible, meaning they could be passed to another person through close contact. If you notice any signs of infection, such as increased redness, swelling, warmth, or pus, consult your dermatologist promptly.

HS isn’t caused by sexually transmitted infections (STIs). While HS symptoms often occur near the genitals and anus, they are unrelated to STIs and cannot be transmitted through sexual contact.

There is also no connection between HS and poor personal hygiene. HS is associated with immune system factors, genetics, and hormones rather than cleanliness. That said, good hygiene practices are often part of managing HS symptoms effectively.

The History of Hidradenitis Suppurativa

Hidradenitis suppurativa likely dates back through human history. However, its name, causes, and medical classification have been debated among researchers for more than a century.

French surgeon Dr. Alfred-Armand-Louis-Marie Velpeau first described hidradenitis suppurativa in the 1830s. Velpeau suggested HS was caused by rubbing, irritation, and lack of cleanliness. In 1854 another French surgeon, Dr. Aristide Auguste Stanislas Verneuil made the connection that HS originates within the sweat glands. HS was known as “Verneuil’s disease” for many years due to his writings. The term “hidradenitis suppurativa” gradually replaced this. It’s derived from the ancient Greek words for:

• Water (hydro)
• Gland (adeno)
• Inflammation (-itis)
• To form pus (suppurare)

In the late 1800s, French dermatologist Dr. Pierre-Antoine-Ernest Bazin wrote his opinion that HS was a type of syphilis, which was a controversial proposal. Around the same time, researchers noted that German philosopher Karl Marx experienced severe skin disease, which, based on his descriptions, is now believed to have been HS.

In the early 1900s, German scientist Dr. Paul Schiefferdecker identified the two types of sweat glands: eccrine and apocrine. Since HS mainly affects areas of the skin containing apocrine glands, it then became known as “apocrinitis.”

In 1989, American dermatologists Dr. Gerd Plewig and Dr. Albert Kligman recommended hidradenitis suppurativa instead be known as “acne inversa.” However, this term never gained wide use. Also in 1989, Dr. H.J. Hurley published a system for staging HS by severity. Most physicians still use the Hurley system to describe the severity of HS cases from 1 (mild) through 3 (severe).

In 1990, Dr. Carmen C.W. Yu published the results of her microscopic study of HS tissue and theorized that HS likely begins with follicular occlusion (blocked hair follicles).

In the 21st century, research has focused on abnormalities in the sweat glands and the immune system that may lead to the development of HS. This research is leading to new approaches to treating HS. Scientists have also been researching more about the genetic links to the development of HS. Understanding more about this connection may help researchers better target the disease with new treatments.

In 2015, adalimumab (Humira) became the first medication approved by the U.S. Food and Drug Administration (FDA) to treat hidradenitis suppurativa. Since Humira was approved, other biologics have debuted. In 2024, the FDA approved another biologic drug, secukinumab (Cosentyx) for treating HS. In 2024, bimekizumab (Bimzelx) was approved in Europe for treating HS, but it’s not yet approved in the U.S. Several of these biologics, including adalimumab and secukinumab, were originally developed for other autoimmune and inflammatory conditions.

How Common Is Hidradenitis Suppurativa?

Hidradenitis suppurativa is not a rare condition. An estimated 1 percent of the population lives with the condition. According to research in Clinics in Dermatology, HS affects approximately three times as many women as men in North America and Europe, but in East Asian countries, such as South Korea and Japan, the condition is more common in males. Men tend to have more severe cases than women do, according to research in the International Journal of Women’s Dermatology.

Among people in the United States, the prevalence of HS is highest among African American populations (1.3 percent), followed by white populations (0.75 percent), according to research in the Journal of Cutaneous Medicine and Surgery. Per the research, the prevalence is lower among Hispanic/Latinos (0.07 percent) and other racial groups (0.17 percent). This suggests a possible genetic link to HS, but more research is needed to understand its prevalence and causes across different populations globally.

How Does Hidradenitis Suppurativa Progress?

HS symptoms often start with one painful bump that persists for a few weeks or months. In some cases, HS symptoms remain mild. In other cases, people develop more lesions that become more severe. Some people with HS find their symptoms diminish after menopause. Early HS diagnosis and treatment can help prevent cases from progressing from mild to severe.

The Hurley staging system is used to classify stages of hidradenitis suppurativa. HS is described as stage 1 (mild), stage 2 (moderate), and stage 3 (severe).

Stage 1 cases of HS usually involve just one or isolated lesions. If you progress to stage 2, you might develop recurring skin lesions with sinus tract formation (narrow openings underneath the skin) and scarring. If HS progresses to stage 3, you may experience recurring lesions across large areas of the body with sinus tract formation, extensive scarring, and foul-smelling pus.

Only about 4 percent to 7 percent of HS cases are classified as stage 3. The majority of HS cases are classified as stage 1 (55 percent to 70 percent) and stage 2 (28 percent).

How Is Hidradenitis Suppurativa Treated?

Several HS treatment options can help manage symptoms, minimize disease progression, and, in some cases, lead to long periods of remission. Mild and moderate HS can often be treated with topical (applied to the skin), oral (taken by mouth), or injected medications. Severe HS may require surgery.

Work With Your Doctor

Living with hidradenitis suppurativa can be challenging, as the painful recurring skin lesions can significantly impact quality of life. However, with proper care, HS is manageable, and many people can achieve meaningful relief.

Finding an effective treatment plan often takes time, as individuals respond differently to medications, lifestyle adjustments, and, in some cases, surgical interventions. Working closely with a knowledgeable doctor is essential — honest, proactive communication about your symptoms, lifestyle, and treatment preferences can help you and your health care provider tailor a plan that best meets your needs.

With persistence and the right support, you can keep HS under better control and improve your quality of life.

Talk With Others Who Understand

On myHSteam, the social network for people with hidradenitis suppurativa, more than 44,000 members come together to ask questions, give advice, and share their stories with others who understand life with HS.

How long have you had HS? What has your diagnosis and treatment journey been like? Share your experience in the comments below, or start a conversation by posting on your Activities page.