Symptoms and causes

Symptoms

Hidradenitis suppurativa commonly occurs around hair follicles with many oil and sweat glands, such as in the armpits, groin and anal area. It may also occur where skin rubs together, such as the inner thighs, under the breasts and between the buttocks. Hidradenitis suppurativa can affect one spot or multiple areas of the body.

Signs and symptoms of hidradenitis suppurativa include:

  • Blackheads. Small pitted areas of skin containing blackheads — often appearing in pairs or a "double-barreled" pattern — are a common feature.
  • Red, tender bumps. These bumps often enlarge, break open and drain pus. The drainage may have an odor. Itching and burning may accompany the bumps. They usually appear in areas where skin rubs against skin.
  • Painful, pea-sized lumps. These hard lumps, which develop under the skin, may persist for years, enlarge and become inflamed.
  • Tunnels. Over time, tracts connecting the lumps may form under the skin. These wounds heal very slowly, if at all, and can leak pus.

Hidradenitis suppurativa usually starts between puberty and age 40 with a single, painful bump that persists for weeks or months. For some people, the disease progressively worsens and affects multiple areas of their body. Other people experience only mild symptoms. Excess weight, stress, hormonal changes, heat or humidity can worsen symptoms. In women, the disease severity may lessen after menopause.

When to see a doctor

Early detection of hidradenitis suppurativa is key to getting effective treatment. See your doctor if your condition:

  • Is painful
  • Doesn't improve in a few weeks
  • Returns within weeks of treatment
  • Appears in several locations
  • Recurs often

If you've already received a diagnosis of hidradenitis suppurativa, keep in mind that the warning signs of a disease flare (recurrence) are often similar to those that occurred originally. Also pay attention to any new signs or symptoms. These may indicate either a recurrence or a complication of treatment.

Causes

Hidradenitis suppurativa develops when hair follicles become blocked and inflamed. No one knows exactly why this blockage occurs. Factors that may play a role include hormones, metabolic syndrome, genetics, an irregular immune system response, smoking and excess weight.

Hidradentitis suppurativa is not caused by an infection and can't be transmitted sexually. It's not contagious and is not due to poor hygiene.

Risk factors

Factors that may increase your risk may include:

  • Age. Hidradenitis suppurativa most commonly occurs in women between the ages of 20 and 29. An early age of onset may be associated with developing more widespread disease.
  • Your sex. Women are more likely to develop hidradenitis suppurativa than are men.
  • Family history. A tendency to develop hidradenitis suppurativa can be inherited.
  • Having certain other conditions. Hidradenitis suppurativa can be associated with several other conditions, including arthritis, severe acne, obesity, inflammatory bowel disease, Crohn's disease, metabolic syndrome and diabetes.
  • Smoking. Smoking tobacco has been linked to hidradenitis suppurativa.

Complications

Persistent and severe hidradenitis suppurativa often causes complications, including:

  • Infection. The affected area is susceptible to infection.
  • Scars and skin changes. The wounds may heal but leave rope-like scars, pitted skin or patches of skin that are darker than normal.
  • Restricted movement. Sores and scar tissue may cause limited or painful movement, especially when the disease affects the armpits or thighs.
  • Obstructed lymph drainage. The most common sites for hidradenitis suppurativa also contain many lymph nodes. Scar tissue can interfere with the lymph drainage system, which may result in swelling in the arms, legs or genitals.
  • Social isolation. The location, drainage and odor of the sores can cause embarrassment and reluctance to go out in public, leading to sadness or depression.
  • Cancer. Rarely, patients with advanced hidradenitis suppurativa can develop squamous cell carcinoma in the affected skin.