Hidradenitis suppurativa (HS) is when recurring inflamed nodules (small, solid lumps) and cysts (fluid-filled mass) form in the armpits and groin. These may also be found under the breasts and around the nipples and anus.

The lesions start as plugged pores in the sweat and oil glands. Material builds up under the skin. The body's inflammatory system attacks these materials. This causes nodules and cysts to form. These lesions can burst under the skin and form an abscess. The area may have a bad smell and may heal and leave a scar.

It is rare to have another infection in these lesions. When it does occur, the bacterium is typically Staphylococcus aureus ("staph"). But, HS is different from true staph infections that cause unrelated conditions (eg, boils , carbuncles). Pilonidal cysts may be seen with HS, but may also occur alone.

These factors increase your chance of developing HS. Tell your doctor if you have any of these:

• Genetics
• Obesity alone or with polycystic ovarian syndrome (PCOS) , insulin resistance, or syndrome X
• Androgen dysfunction (excess male hormone)
• Crohn’s disease and related conditions
• Acne
• Dissecting cellulitis of the scalp
• Medications (eg, lithium )
• Smoking (interferes with healing)

If you have any of these symptoms do not assume it is due to HS. These symptoms may be caused by other conditions. Tell your doctor if you have any of these:

• Painful swellings in the armpits, groin, under the breasts, around the nipples, or around the anus
• Pus leaking from openings in the swellings
• Foul smell from the affected areas
• Scarring
• Feeling depressed or isolated because of symptoms

See your doctor right away before HS worsens.

Your doctor will ask about your symptoms and medical history, and perform a physical exam. The exam will include every crease and fold on your body that might be affected. Tell the doctor about every lump, even those that are not visible.

You may need to see a dermatologist or a surgeon. If this is the case, find one with experience in treating abscesses and sinuses.

Tests may include:

• Culture of the drainage to identify the bacteria

Talk with your doctor about the best treatment plan for you. There are various options. Some are more effective than others.

This treatment is uncertain. Hot packs or warm baths may be used to soften the skin and allow the abscess to drain.

Long-term use of antibiotics may help stop inflammation. Taking antibiotics this way, though, could lower your resistance to infections.

Cortisone , taken orally for a few days, has shown to be effective in the short-term. Because of side effects, this drug should not be used over the long-term. Cortisone can also be injected or applied to the skin, which may reduce some of the side effects

Controlling the male hormone (androgen) may also help. Examples include:

• Cyproterone acetate—used either alone or combined with ethinyl estradiol , can suppress acne in women and has improved HS (not available in the US)
• Drospirenone (available as a birth control pill)
• Flutamide
• Finasteride
• Dutasteride
• Spironolactone

Small lesions can be treated in the doctor's office, which could require several visits. If your condition is severe, then a wide area may need to be removed. In these cases, a skin graft may be needed.

During this treatment, a laser is used to remove the lesions.

Infliximab and etanercept are called "biologic medications." They are used to treat a inflammatory conditions, such as rheumatoid arthritis . These drugs have shown some promise in treating severe HS. Although, they must be injected under the skin and can cause serious side effects.