Pilonidal disease is a type of skin infection which typically occurs between the checks of the buttocks and often at the upper end. Symptoms may include pain, swelling, and redness. There may also be drainage of fluid. It rarely results in a fever.
Risk factors include obesity, family history, prolonged sitting, greater amounts of hair, and not enough exercise. The underlying mechanism is believed to involve a mechanical process. The lesions may contains hair and skin debris. Diagnosis is based on symptoms and examination.
If there is infection, treatment is generally by incision and drainage just off the midline. Shaving the area may prevent recurrence. More extensive surgery may be required if the disease recurs. Antibiotics are generally not needed. Without treatment the condition may remain long term.
About 3 per 10,000 people are affected a year. It occurs more often in males than females. Often it occurs in young adulthood. The term means "nest of hair". It was first described in 1833.