What is a pilonidal cyst?

A pilonidal cyst is a round sac of tissue that's filled with air or fluid. This common type of cyst is located in the crease of the buttocks and is usually caused by a skin infection. Pilonidal cysts are a common condition, with more than 70,000 cases reported in the U.S. every year. But many people feel too embarrassed to mention it – even to their healthcare providers.

Pilonidal cysts can cause pain and need to be treated. Pilonidal cysts can be a one-time (acute) problem or you may have chronic (returning) cysts. If they’re not treated, chronic pilonidal cysts can also lead to abscesses (swollen pockets of infection) and sinus cavities (empty spaces underneath the skin).

A pilonidal cyst (also called pilonidal cyst disease, intergluteal pilonidal disease or pilonidal sinus) is a skin condition that happens in the crease of the buttocks — anywhere from the tailbone to the anus. A pilonidal cyst can be extremely painful especially when sitting.

These cysts are usually caused by a skin infection and they often have ingrown hairs inside. During World War II, pilonidal cysts were often called "Jeep driver's disease” because they’re more common in people who sit often.

Who can get a pilonidal cyst?

Anyone can get a pilonidal cyst, but certain people are at higher risk:

  • Men (men are three to four times more likely to be diagnosed with a pilonidal cyst than women)
  • People between puberty and age 40 (the average age is between 20 and 35).
  • Workers who sit all day (like truck drivers and office workers).
  • Overweight people (ranging from overweight to obese).
  • People with thick or rough body hair (this can run in your family).
  • People who wear tight clothing (this can worsen the skin condition).

Is a pilonidal cyst hereditary?

In some cases, a pilonidal cyst can be hereditary (you can inherit it from a family member). Your family history can play a role in determining if you get pilonidal cysts, for example if rough body hair runs in your family.

Is a pilonidal cyst contagious?

A pilonidal cyst is a non-contagious skin condition – you can’t spread it (just like a pimple). Currently, many researchers believe that pilonidal cysts are caused by ingrown hairs.

What causes a pilonidal cyst?

Experts don’t yet know all the causes of pilonidal cysts. However, they do know that ingrown hairs found in the crease of the buttocks result in a skin infection that causes a pilonidal cyst to form. Think of this condition like getting a sliver of wood stuck in your skin, except it’s an ingrown hair instead.

If it’s not treated, a pilonidal cyst can possibly lead to an abscess or a sinus cavity. Those are both signs that the skin infection is getting worse.

What are the symptoms of a pilonidal cyst?

  • Quickly get medical attention if you notice any of these symptoms:
  • Pain which often gets worse when you’re sitting.
  • A small dimple or large swollen area between your buttocks. This is usually the pilonidal cyst. You may notice the area is red and feels tender.
  • An abscess with draining pus or blood. This fluid may be foul-smelling.
  • Nausea, fever and extreme tiredness (fatigue).

Can I get a pilonidal cyst while I’m pregnant?

Although pilonidal cysts are much more common in men, pregnant women can get them too. If you’re experiencing pain in your buttocks, it could be a sign of a pilonidal cyst and not just a normal discomfort of pregnancy. It’s usually best in that case to contact your provider and get checked.

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