Hidradenitis suppurativa (HS) is a painful chronic skin condition that affects sweat glands in different areas of the body. HS is characterized by boil-like lumps or lesions found beneath the skin. The armpits, anal region, groin and the sweat glands of the breast and scalp may be involved. These unsightly lesions can become itchy, inflamed and painful and may fill with pus. These pockets of infection can rupture and begin to leak a malodorous fluid. When these abscesses heal, severe scarring results.

The cause of HS is unknown, but the condition usually starts with a blockage of the hair follicles that results in infection and inflammation. The onset of symptoms is sometimes prefaced by itchiness or an uncomfortable feeling.

After lesions heal, scars can form, which sometimes leads to tunnels under the skin, called sinus tracts. The process of repeated healing and recurrences causes pitted skin and ropelike scar tissue to develop, which can become disabling if the problem covers a widespread area.

Suspected triggers for HS include weight gain, menstruation in women, hormonal changes, heat, smoking and sweating. In addition, HS may be hereditary—some people have a family history of the condition—or caused by environmental factors or gene mutations. (The condition is not caused by poor hygiene and is not contagious.)

Hidradenitis suppurativa occurs most often in females in the area where the shoulder meets the arm and the vulvar region of the genitals. Men also get HS, usually around the anus. Affected individuals are frequently in their teens or 20s.

Clinical symptoms of HS can range from mild to moderate to severe. Mild symptoms may involve one area of the skin with one or only a few bumps. Moderate HS involves recurring lumps that become progressively bigger and break open. In severe cases of HS, lumps are extensive, and scarring and chronic pain can create mobility issues.

The condition is diagnosed in three stages—Hurley stages 1, 2 or 3—that depend on the area involved. Each stage is treated differently, but the goal is to prevent the disease’s progression to Hurley Stage 3. There is no definitive cure for HS and advancement may be inevitable.

People with this condition are also at risk for depression because of the stigma associated with the disease, which can cause social isolation.

HS can go undiagnosed for many years because individuals feel ashamed of their symptoms.   Diagnosis is based on the symptoms people experience, medical history, physical examination and blood tests.

Special exams, such as an ultrasound to check hair follicles and skin thickness and a urine analysis, can be used to assess the disease’s progression.

Although HS symptoms may appear alarming, the condition is rarely life-threatening. However, in those with a weakened immune system, complications from HS that cause an infection affecting the entire body can cause death.

For the best health outcomes, doctors recommend early diagnosis and treatment. Medications can help manage symptoms and stop the formation of new boils and lesions.