Pilonidal cysts are cysts that typically develop along the tailbone (coccyx), near the natal cleft of the buttocks. While the exact cause is unknown, it is believed that pilonidal cysts develop from ingrown hairs, which cause a local inflammatory response. These cysts typically contain hair and skin debris in addition to abnormal tissue. Pilonidal cysts are most common in males, but are also common in hirsute individuals (those with excessive hair), obese individuals, individuals with a family history of pilonidal cysts, and individuals with sedentary occupations. Individuals that experience excessive pressure or continued trauma to the sacrococcygeal area are at a higher risk of developing these cysts.
Pilonidal cysts may be asymptomatic (causing no noticeable symptoms), making diagnosis difficult. For some individuals, the cyst may appear as an opening or pit on the skin. Pilonidal cysts are most noticeable following infection. An infected cyst may cause redness and warmth of the skin as the cyst becomes an abscess. The swollen mass may cause localized pain and swelling, as well as drainage of pus or blood from the pulonidal sinus. Some patients may notice that the drained pus has a distinctive odor. In certain cases, patients may experience pain and swelling over the lower spine, and in rare cases, patients may develop a fever.
Once a pilonidal cyst has become infected, it requires surgical removal and drainage to heal. The area is typically numbed with an injection of local anesthesia, followed by an incision made in the infected area. The pus is allowed to drain, and then the hair and debris are removed from the wound. The wound is then packed with gauze and allowed to heal. Unless there is the risk of cellulitis, antibiotics are rarely prescribed. Pain medication may be prescribed as needed by the patient. More complicated pilonidal cysts may require more invasive surgical measures, and will be discussed following diagnosis. Follow-up is typically required to ensure that the wound is healing properly and that there is no further infection.