A pilonidal cyst is a small pit, or dimpled area that can occur anywhere along the crease between the buttocks (sacral area).
Alternative NamesSacral dimple; Pilonidal dimple; Pilonidal sinus
ConsiderationsMost 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.
Common CausesThe 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.
Home CareIt may be helpful to keep the area clean and dry and remove hair regularly to help prevent infection.
Call your health care provider ifCall your health care provider if you notice swelling, redness, drainage, or tenderness around the pilonidal cyst.
What to expect at your health care provider's officeYou will be asked for your medical history and given a physical examination. Sometimes you may be asked for the following information:
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.
ReferencesKlein 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.
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A pilonidal cyst is a painful lump that develops at the base of the tailbone. It can become infected and filled with pus, causing pain, swelling, and drainage. Treatment may involve antibiotics, draining the cyst, or surgical removal.