Pilonidal cyst

Definition

A pilonidal cyst is a small pit, or dimpled area that can occur anywhere along the crease between the buttocks (sacral area).

Sacral dimple; Pilonidal dimple; Pilonidal sinus

Most pilonidal cysts are pits or small depressions that are present from birth. They may range from a small dimple to a deep tract with hair in or around it.There may be more than one pit present. Very rarely, the pilonidal cyst may reach the spinal cord.

A pilonidal cyst may become infected, forming what is called a pilonidal abscess. This may require surgical drainage. If repeated infection occurs, surgery may be done to remove it.

The cause of pilonidal cysts is not certain. These cysts may be congenital (present from birth). In some cases, they might be caused by hair growing into the skin. This may occur with excess body hair, tight clothing, or sitting for long periods of time.

It may be helpful to keep the area clean and dry and remove hair regularly to help prevent infection.

Call your health care provider if you notice swelling, redness, drainage, or tenderness around the pilonidal cyst.

You will be asked for your medical history and given a physical examination. Sometimes you may be asked for the following information:

• Has there been any change in the appearance of the pilonidal cyst?
• Has there been any drainage from the dimple?
• Are any other symptoms developing?
• What other symptoms are also present?
• Is there any numbness or loss of movement in the legs?
• Has there been any change in bladder control?

Most pilonidal cysts will not cause any symptoms and can be left alone. Rarely, tests may be done to determine if the pilonidal cyst extends to the spinal cord.

Klein MD, Thomas RP. Surgical conditions of the anus, rectum, and colon. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics. 18th ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 341.

Nelson H, Cima RR. Anus. In: Townsend CM Jr, Beauchamp RD, Evers BM, Mattox KL, eds. Sabiston Textbook of Surgery. 18th ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 51.