Why Does Hidradenitis Suppurativa Smell?

hidradenitis suppurativa
Hidradenitis suppurativa (HS) usually smells when HS cysts/boils break open and ooze pus

Hidradenitis suppurativa (HS) usually smells when HS cysts/boils break open and ooze pus. The smell is from the content of the cyst, which consists of bacteria and broken down cells from human tissue.

Anaerobic bacteria, a type of bacteria that thrive in low oxygen conditions in wounds, often infect HS cysts. The bacteria degrade the white cells that attack them, as well as other cells in the tissue. The degraded cells release chemical compounds that have a distinctive, unpleasant odor.

What is hidradenitis suppurativa?

Hidradenitis suppurativa, also known as acne inversa, is an inflammatory skin disease that causes lumps under the skin around hair follicles or in areas where skin rubs against skin. These lumps can get infected and form painful abscesses which can rupture, leak pus and leave the skin thickly scarred.

The term “hidradenitis” means inflammation of sweat gland, and “suppurativa” means pus-forming, in Greek. HS lesions primarily tend to occur in the armpits, groin and pubic areas where special sweat glands known as apocrine glands (also termed scent glands) are abundant, but they can also occur around the  the nipples on the breasts, on the inner thighs or around the anal area.

Hidradenitis typically starts with just one painful bump which may look like a pimple or acne. As the disease progresses more cysts form, join together and grow, either recurring in the same area or in other parts of the body. In some people, abnormal tunnels in the tissue known as sinus tracts form under the skin, which connect the abscesses.

Hidradenitis suppurativa is classified into three stages known as Hurley stages, based on the severity of the condition:

  • Hurley stage I: One or more isolated abscess formation
  • Hurley stage II: Single or multiple separate lesions and recurrent abscesses with sinus tracts and scarring
  • Hurley stage III: Multiple interconnected sinus tracts and abscesses covering an entire area

What are the symptoms of hidradenitis suppurativa?

Hidradenitis usually occurs on both sides of the body. Hidradenitis symptoms can be mild and merely irritating for some, but can be extremely painful and physically and mentally distressing for others. HS abscesses can cause:

Hidradenitis is not always progressive, but persistent breakouts can lead to:

What is the cause of hidradenitis suppurativa?

Hidradenitis suppurativa begins with excessive growth of keratinocytes, a type of cell in the skin. The keratin overgrowth clogs up the hair follicles and the apocrine gland’s ducts, and traps the sweat within the hair follicles. Abnormal functioning of the apocrine gland may also be a contributing factor to the clogging of the ducts.

The HS lump forms when the trapped sweat builds up, and the skin in the area gets inflamed and tender. The lump can grow into a painful boil under the skin until it bursts. If the boil gets infected with the bacteria in the skin, it becomes an abscess filled with pus which has an unpleasant odor when it drains.

It is not clear why the keratin overgrowth and follicle clogging occurs in some people, but hidradenitis is not caused by poor hygiene, nor is it contagious. Research indicates that HS is associated with the following risk factors:

  • Age: HS most often begins around puberty or in young adults. The risk for HS drops after the age of 50.
  • Gender: HS is more common among women than men.
  • Genetics: Research indicates genetic involvement because HS often runs in families.
  • Hormones: Hormones are thought to play a role because HS is more common during the reproductive years. Many women with HS also have excess hair growth (hirsutism) which is related to excess androgen, the male hormone. Androgen stimulates apocrine glands, while estrogen, the female hormone, suppresses their activity.
  • Immune disorders: HS is an inflammatory condition and overreaction of immune cells in the skin is a possible contributing factor. People with HS often have other inflammatory diseases such as arthritis, Crohn’s disease or severe acne.
  • Obesity: Obesity can alter the metabolism of sex hormones and lead to excess androgen. Obesity can also increase the risk for HS because of moist skin folds constantly rubbing together.
  • Smoking: Research shows smoking can aggravate HS.

What triggers hidradenitis suppurativa?

Hidradenitis suppurativa flares may be triggered by:


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What is the best treatment for hidradenitis suppurativa?

There is no known cure for HS but early treatment can help manage the symptoms effectively and prevent flare ups. Treatment for HS is individualized and depends on the severity of the condition. HS may require one or more of the following treatments:

Warm compresses

Applying a warm compress to the affected area can help bring the boil to a head and drain it, which can bring down the pain. Warm compresses are useful as home treatment for mild cases of HS.


Medications for HS may include:

  • Anti-inflammatory non-steroidal drugs (NSAIDs): NSAIDs help reduce pain and inflammation.
  • Antibiotics: Oral and/or topical antibiotics are used to treat infected lesions.
  • Corticosteroids: Corticosteroids are potent anti-inflammatory drugs that are injected into the HS lesions, or taken orally in severe cases.
  • Oral retinoids: Retinoids are medications which can induce dead skin cells to shed and reduce clogging, usually used for severe HS.
  • Hormone therapy: Hormone therapy involves birth control pills or a drug known as spironolactone, which reduces the secretion of androgen and is helpful for some women.
  • Immunosuppressants: Immunosuppressants are biologic antibodies which block skin’s immune activity and help prevent inflammation.


Surgical procedures include:

  • Incision and drainage: Lancing the boils and draining them, useful for mild cases with isolated boils in a small area.
  • Laser surgery: Use of laser beam to destroy the affected hair follicles.
  • Deroofing: Cutting open the tunnels connecting the lesions, which helps with healing the lesions.
  • Tissue removal and grafting: Surgical removal of the affected skin tissue and covering it with skin graft from another part of the body.
  • Carbon dioxide laser therapy: Precise removal of layers of affected skin which leaves an open wound that can be allowed to heal.

How can HS be prevented?

HS flares can be reduced by making healthy lifestyle choices. Following are some tips to prevent or control HS flares:

  • Try to identify and avoid your HS triggers
  • Eat nutritious food and maintain a healthy weight
  • Avoid smoking
  • Keep the skin cool
  • Use gentle soaps and avoid skin products that can irritate
  • Wear comfortable loose-fitting clothes
  • Practice relaxing techniques to manage stress