A pilonidal cyst is a cystic structure that develops along the tailbone near the cleft of the buttocks, approximately 4 cm to 5 cm from the anus. These cysts usually contain hair and skin debris. Individuals with a pilonidal cyst may not have any symptoms at all, whereas others may develop an infection of the cyst with associated pain and inflammation. The treatment and management of pilonidal cysts depends on many factors, including the extent and chronicity of the disease. Recurrence of pilonidal cysts is common and is estimated to occur in approximately 40%-50% of individuals.
Pilonidal cysts were first described in 1833 by Herbert Mayo. The term pilonidal is derived from the Latin words "pilus" (hair) and "nidus" (nest) and was coined in 1880 by R.M. Hodge. The incidence of pilonidal cysts has been estimated to be about 26 cases per 100,000 people. Pilonidal cysts occur more frequently in men than in women, and they are more common in Caucasians than in other racial groups. Pilonidal cysts usually occur between the ages of 15 to 24, and their development is uncommon after the age of 40.
Causes
Although there are several theories as to the causes and origins of pilonidal disease, most researchers today believe that pilonidal cysts are acquired (rather than congenital, or inborn) and that they are caused by the penetration of loose hairs into the skin through dilated hair follicles into the subcutaneous tissues. In response to this ingrown hair, a local inflammatory reaction causes a cystic structure to form around the hair and the other skin debris. Excessive pressure or repetitive trauma to the sacrococcygeal area are thought to predispose individuals to develop the cyst or to irritate an already existing pilonidal cyst.
During World War II, more than 80,000 U.S. soldiers developed pilonidal cysts requiring hospitalization. Because so many of the afflicted servicemen rode in bumpy Jeeps for prolonged periods of time, the condition was