Pilonidal disease

Pilonidal disease
Other names	Pilonidal cyst, pilonidal abscess, pilonidal sinus, sacrococcygeal cyst / fistula
Acute pilonidal disease (abscess) in the upper gluteal cleft
Specialty	General surgery, colorectal surgery
Symptoms	Pain, swelling, redness, drainage of fluid[1]
Usual onset	Young adulthood[2]
Causes	Ingrown hair in the natal cleft
Risk factors	Obesity, family history, greater amounts of hair (hirsutism), not enough exercise[2]
Diagnostic method	Based on symptoms and examination[2]
Differential diagnosis	Hidradenitis suppurativa, perianal abscess, folliculitis[2]
Prevention	Shaving the area[1]
Treatment	Incision and drainage,[2] surgical removal
Frequency	3 per 10,000 per year[2]

Pilonidal disease is a type of skin infection which typically occurs as a cyst between the cheeks of the buttocks and often at the upper end.^[1][3] Symptoms may include pain, swelling, and redness.^[1] There may also be drainage of fluid, but rarely a fever.^[1][2]

Risk factors include obesity, family history, prolonged sitting, greater amounts of hair, and not enough exercise.^[2] The underlying mechanism is believed to involve a mechanical process where hair and skin debris get sucked into the subcutaneous tissues through skin openings called pits.^[2] Diagnosis is based on symptoms and examination.^[2]

If there is infection, treatment is generally by incision and drainage just off the midline.^[1][2] Shaving the area and laser hair removal may prevent recurrence.^[1][4] More extensive surgery may be required if the disease recurs.^[1] Antibiotics are usually not needed.^[2] Without treatment the condition may remain long term.^[1]

About 3 per 10,000 people per year are affected, and it occurs more often in males than females.^[2] Young adults are most commonly affected.^[2] The term pilonidal means 'nest of hair'.^[1] The condition was first described in 1833.^[1]