Between 1 and 4 percent of the population – an estimated 3.2 to 13 million Americans – live with hidradenitis suppurativa (HS), a skin condition characterized by painful bumps and sores in the skin.2 HS bumps may last for months, heal and recur repeatedly, form scars, or burst and leak foul-smelling pus. HS, also known as acne inversa, acne ectopica, apocrine acne, Verneuil’s disease, or fox den disease, can have a negative effect on the quality of life and often proves difficult to treat.1, 3, 4
Hidradenitis suppurativa is often mistaken for other skin conditions including acne, boils, cysts, and folliculitis. Like acne, HS forms when the hair follicles clog with bacteria and other substances. However, HS is caused by a problem in the immune system rather than a blocked pore or an infection. Because HS can look like common skin conditions, it is best to see a dermatologist for diagnosis.5
HS can occur at any age but often develops between the ages of 20 and 30. It is more common in women than in men by a ratio of three to one.6 Early diagnosis and treatment can help manage HS symptoms, prevent progression, and avoid complications such as scarring. Unfortunately, there is an average seven-year delay in diagnosis.7 Depression and self-imposed isolation are common among people with HS, as the pain and visible effects on the skin take an emotional toll.8
What Causes Hidradenitis Suppurativa?
Hidradenitis suppurativa is a chronic inflammatory skin condition brought on by irregularities in the immune system.9 Some researchers believe that HS develops when the immune system overreacts to a plugged hair follicle.10
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 is limited to parts of the skin containing apocrine sweat glands.11 Areas with apocrine sweat glands include:
Women tend to develop HS more commonly in the armpits, groin, and under the breasts.11 Men more commonly develop HS in the skin around the anus.11 In some people, the nape of the neck and the skin behind the ears can be affected as well.2
What Are the Symptoms of HS?
The disease usually starts with a single, painful bump that persists for weeks or months. Some people only experience mild symptoms, but for others, HS gets progressively worse.11
Symptoms of HS can include double-headed 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 months.12
Swollen lumps associated with HS may spontaneously rupture with a foul-smelling discharge, and may heal and then recur. Lesions sometimes fuse into dermal abscesses. These abscesses may leak pus and can be hard to heal. Fistulas can also form, leading to the development of extensive tunnels under the skin known as sinus tracts.7
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 body movement in affected areas.12
Some people with HS also experience itching, burning, and profuse sweating.13
HS can impact the quality of life by causing psychological symptoms such as depression, anxiety, stress, low self-esteem, social isolation, and problems with intimacy.14
Who Is at Risk for Hidradenitis Suppurativa?
Hidradenitis suppurativa affects between 1 and 4 percent of the global population.2 HS is three times more common in women than in men.6 People of African and European descent have a higher risk of developing HS, while it is rare among those of Asian background.11
In the U.S., African-American women aged 40 and under have the highest risk of developing hidradenitis suppurativa in comparison to other ethnic and age groups.7
HS usually begins around puberty when hormone levels rise and activate the apocrine sweat glands.10 Few people develop HS before 11 years of age, and if they do, it is often a case of early puberty.10 Developing HS after menopause or 55 years of age is rare.10
Genetics play a role in the development of hidradenitis suppurativa. About one-third of people who develop HS have a blood relative with the condition.10
Tobacco use may be a risk factor for developing hidradenitis suppurativa. While the connection requires further research, there is evidence that HS is more common among smokers than nonsmokers. A study of 50 million Americans found that smokers were almost twice as likely to be diagnosed with HS than nonsmokers. Other studies have found a relationship between smoking and greater HS severity.15
Obesity or being overweight may not be direct causes of HS, however they are associated with more severe symptoms. A study of 115 people with hidradenitis suppurativa found that people with a body mass index (BMI) considered obese had more severe symptoms than those without. Individuals with an overweight BMI had more severe symptoms than those with a normal BMI.16
HS also seems more common in people with acne, and may be more common in women with polycystic ovary syndrome (PCOS).11
Common Myths About HS
There are many common misconceptions about hidradenitis suppurativa that contribute to stigma around this painful and sometimes debilitating condition. Here’s the truth behind several of the most common myths.
HS cannot be spread from one person to another. It is believed to be caused by a malfunctioning immune system.17
HS is not contagious and is not caused by any type of infection. HS lesions often develop around the genitals and anus because these areas contain apocrine glands.
Dermatologists have determined that HS is not caused by poor hygiene.10 HS is caused by a malfunction with the immune system and may start with an immune reaction to a plugged hair follicle.10
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 and 4 percent of the population, or 3.2 to 13 million Americans.2
What Are the Stages of HS?
Dermatologists describe cases of hidradenitis suppurativa from mild to severe using a system known as Hurley stages.2 Mild cases can consist of small bumps on the skin, blackheads, or a few skin cysts.5 More severe forms can lead to recurrent abscesses, which sometimes release foul-smelling fluid.5
The three Hurley stages are defined by the following symptoms:
Some doctors also use the modified Sartorius score, designed in 2003. It was the first validated HS-dedicated tool and is based on four clinical parameters including which parts of the body are involved, the number and type of lesions, and the distance between lesions. The Sartorius score is used more for research than in daily clinical practice.20
Not all cases of hidradenitis suppurativa progress to more advanced stages, but some cases of HS can continue to reappear and grow more severe if not properly managed. Diagnosing and properly 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 certain biologics, improve symptoms in some people with HS. 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. Another option for some women is hormone therapy.9 Currently only 1 biologic (adalimumab) has been appoved by FDA and EMA for the treatment of HS.
In some people, HS proves difficult to treat and does not respond to medications. Surgery can be effective in treating people who have had HS for a longer period of time. Surgery is sometimes successful in rendering HS inactive over long periods, though sores may recur.22 For severe cases of HS that do not respond to other treatments, radiation therapy may be an option.4
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 (CBT), meditation, or by engaging with a support group, either in person or on myHSteam.14 If you are feeling depressed, talk with your doctor about treatment. Antidepressant medication may be an effective treatment for some people.
Home remedies and lifestyle changes help some people with HS feel better. Read 5 Ways to be Proactive About HS.
Health Conditions Associated With HS
Aside from hidradenitis suppurativa itself, some of the most common health conditions that occur along with HS include the following:23
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