DefinitionPilonidal dimple is a condition that can occur anywhere along the crease between the buttocks, which runs from the bone at the bottom of the spine (sacrum) to the anus.Pilonidal dimple may appear as:A pilonidal abscess, in which the hair follicle becomes infected and pus collects in the fat tissueA pilonidal cyst, in which a cyst or hole forms if there has been an abscess for a long timeA pilonidal sinus, in which a tract grows under the skin or deeper from the hair follicleA small pit or pore in the skin that contains dark spots or hairAlternative NamesPilonidal abscess; Pilonidal sinus; Pilonidal cyst; Pilonidal diseaseConsiderationsSymptoms may include:Pus may drain to a small pit in the skinTenderness over the area after you are active or sit for a period of timeWarm, tender, swollen area near the tailboneFever (rare)There may be no symptoms other than a small dent (pit) in the skin in the crease between the buttocks.Common CausesThe cause of pilonidal disease is not clear. It is thought to be caused by hair growing into the skin in the crease between the buttocks.This problem is more likely to occur in people who:Are obeseExperienced trauma or irritation in the areaHave excess body hairSit for long periods of timeWear tight clothingHome CareIt may help to keep the area clean and dry and remove hair regularly to prevent infection.Call your health care provider ifCall your health care provider if you notice any of the following around the pilonidal cyst:Drainage of pusRednessSwellingTendernessWhat 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:Has there been any change in the appearance of the pilonidal cyst?Has there been any drainage from the area?Do you have any other symptoms?Rarely, a CT scan is done.Pilonidal disease that causes no symptoms does not need to be treated.A pilonidal abscess may be opened, drained, and packed with gauze. Antibiotics may be used if there is an infection spreading in the skin or you also have another, more severe illness.Other surgeries that may be needed include:Removal (excision) of the diseased areaSkin graftsSurgery to remove an abscess that returnsReferencesStafford SJ, Klein MD. Pilonidal sinus and abscess. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics. 19th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 336.6.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.Humphries AF, Duncan JE. Evaluation and management of pilonidal disease. Surg Clin North Am. 2010;90:113-124.Reviewed ByReview Date: 11/07/2011Linda J. Vorvick, MD, Medical Director, MEDEX Northwest Division of Physician Assistant Studies, University of Washington, School of Medicine; Susan Storck, MD, FACOG, Chief, Eastside Department of Obstetrics and Gynecology, Group Health Cooperative of Puget Sound, Bellevue, Washington; Clinical Teaching Faculty, Department of Obstetrics and Gynecology, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.