Pilonidal cysts are sacs that develop over the tailbone at the top of the buttocks crease. When ingrown hairs penetrate the skin, infection can occur causing a pilonidal cyst to form.

What Causes Pilonidal Cysts?

Pilonidal cysts occur when a small pocket of skin at the top of the buttocks crease becomes infected and fills with pus. The likely cause appears to be loose or ingrown hairs that work their way through the skin and gather in the sac. Pressure from sitting, friction or force causes hair to penetrate the tissue under the skin leading to abscess.

Pilonidal cysts are most commonly seen in younger men, especially those with sedentary occupations such as truck drivers. They are also more likely to develop in individuals who are overweight or obese or who have thick body hair. Family history also plays a role.

Symptoms of a Pilonidal Cyst

Unless infection is present, individuals with a pilonidal sinus (sac), often experience no signs or symptoms.  When the sac becomes infected, a pimple-like growth forms, the skin around the cyst becomes red and painful. Pus or bloody drainage may occur, sometimes accompanied by a foul odor. Fever may develop if the infection becomes severe.

Treatment of a Pilonidal Cyst

In the case of a serious pilonidal cyst infection, antibiotics are necessary.

Your dermatologist may perform an incision to drain the pilonidal cyst. This can usually be done in the office using a local anesthetic to numb the area.

Once the cyst is drained, the wound may be packed with a medicated dressing and left open to heal from the inside out, or the incision may be stitched closed.

It is possible for a pilonidal cyst to redevelop following treatment. If the cyst returns, your dermatologist may suggest a surgical procedure to remove the entire sac.

To help prevent pilonidal cysts, your dermatologist may recommend losing weight, keeping the area clean and free of hair and reducing sitting time.