Pilonidal cyst derives its name from Latin pilus (hair) and nidus (nest). O.H. Mayo was the first to describe the disease in 1883.


  • Risk factors: male sex, family history, overweight/obese, trauma, irritation, sedentary lifestyle, hirsute habitus, poor hygiene


  • Shed hair is drawn into the gluteal cleft by the motion from the buttocks, which creates a vacuum effect forcing the hair into the skin. The foreign body reaction produced by trapped hair may lead to a hair-filled abscess cavity, which can drain spontaneously through the skin or back through the sinus tracts.

Physical Exam

  • Acute abscess cephalad to the gluteal cleft
  • Sinus openings along the midline of the gluteal cleft, 4 – 8 cm from the anus → hallmark finding


  • Dye (e.g., methylene blue) may be injected for better identification of complicated sinuses. It must be done several days before surgery to avoid excessive staining of the operative area.


Relevant Information

  • The location of a pilonidal cyst is different from a perirectal abscess. Perirectal abscesses are found near the anus.


  • Recurrence
  • Wound breakdown
  • Infection

Differential Diagnoses

  • Abscess
  • Hidradenitis suppurativa
  • IBD
  • Anal fistula
  • Epidural abscess
  • Folliculitis
  • Furuncles
  • Carbuncles