Pilonidal cysts are pockets of skin in the crease of the buttocks near the end of the tailbone (coccyx). They usually begin where ingrown hairs push into the folds of the skin, which irritates and inflames the skin. Pilonidal disease is a chronic infection in the skin slightly above the crease of the buttocks. It develops in a cyst (pilonidal cyst) at the top of or next to the crease of the buttocks (overlying the sacrum). The cyst may look like a small dimple (called a "pit" or "sinus"). Hair may protrude from the pit, and several pits may be seen. Not everything about pilonidal cysts is understood, but there are several well-known facts. Men are affected two to three times more often than are women, and the cysts typically affect those younger than 40.

Who gets pilonidal cysts?

Pilonidal cysts tend to occur in young men since they usually have more body hair, although it can occur in anyone. In a population study of Minnesota college students, pilonidal cysts were found at routine physical exams in 1.1% of males and 0.11% of females. It usually occurs after puberty and is rarely seen after age 40. Incidence is highest in whites and less in Africans and Asians, perhaps due to differences in hair characteristics.

Causes

A pilonidal condition may be congenital or acquired. If congenital, it probably began as a defect that existed when you were born. Sometime later, the defect allowed an infection to develop. If acquired, it may be the enlargement of a simple hair follicle infection or the result of a hair penetrating the skin and causing an infection.

Signs and symptoms

The first sign of a pilonidal cyst is often a slight lump that can be felt over the tailbone in the buttock crease. If the pilonidal cyst becomes larger and inflamed, you may notice pain in the area of your tailbone that worsens with sitting.
The main concern is infection, which can result in a painful abscess. Signs and symptoms of an abscess include pain, localized swelling, redness, fever and drainage of pus.

Treatment

Early in an infection of a pilonidal cyst, the redness, swelling, and pain may be minimal. Sitting in a warm tub may decrease the pain and may decrease the chance that the cyst will develop to the point of requiring incision and drainage.
Incision and drainage procedure. During this procedure, you're given a local anesthetic to numb the area before your doctor opens and drains the cyst. Afterward, your doctor packs the wound so that it can heal from the inside out.

Marsupialization - This procedure involves incision and draining, removal of pus and hair, and sewing of the edges of the fibrous tract to the wound edges to make a pouch.

Surgery. Surgical treatment of recurrent pilonidal cysts usually involves opening and draining infected cysts and cutting away skin and flesh that cover any dimples or pits that could potentially develop into abscesses. The wounds are left open and packed to heal from the inside out. In some cases, the wound is partially sewn to prevent the wound from closing up prematurely. Surgery may be done with local, regional or general anesthesia.