Pilonidal disease

Pilonidal disease, caused by loose hair penetrating the gluteal cleft tissue, can manifest as acute abscesses or chronic cysts and sinuses with persistent drainage. Pilonidal disease is most common in young adult men. Risk factors include a deep gluteal cleft, excessive body hair, prolonged sitting, friction, and PCOS. Symptoms range from mild drainage and erythema to severe pain from abscesses. Chronic pilonidal disease involves recurrent infections and sinus tract discharge. Diagnosis is based on patient history and clinical examination. Treatment depends on severity, from incision and drainage for acute pilonidal abscesses to surgical interventions for chronic pilonidal disease.

• Sex: ♂ > ♀ (∼ 3:1)
• Peak incidence: 15–25 years ^[1]

Epidemiological data refers to the US, unless otherwise specified.

The exact mechanism is unknown, however, the current prevailing hypothesis is that pilonidal disease is an acquired condition.

• Sitting or bending cause hair follicles, in vulnerable skin within a deep gluteal cleft, to stretch and break → formation of an open pore or pit. These open pores either collect debris or broken hair roots (from the head, back or buttocks).
• Movement causes negative pressure (e.g., “suction effect”) and further penetration of hair into local subcutaneous tissue → formation of a pilonidal sinus ^[2]
• These collections trigger local tissue inflammation within the pilonidal sinus → acute infection (abscess) or fistulae ^[3][4]

• Excessive body hair
• Obesity
• Deep gluteal cleft
• Local irritation
• Sedentary lifestyle
• Family history
• PCOS ^[7]

• Pilonidal cyst: a cyst near the upper gluteal cleft, often containing hair and skin debris
• Acute pilonidal abscess: acute infection of a pilonidal cyst
  • Pain
  • Erythema, cellulitis
  • Fluctuant swelling lateral to midline
  • Purulent discharge
  • Possible fever
• Chronic pilonidal disease: presence of pits or persistent sinus tracts without acute abscess formation
  • May be asymptomatic or cause chronic pain
  • Sinus openings (midline pits) may be visible superior (4–8 cm) to the anus.
  • Drainage (purulent, mucoid, or blood‑stained) from sinus tracts
• Recurrent pilonidal disease: repeated episodes of acute infection

• Pilonidal disease is a clinical diagnosis. ^[6][9]
  • Examine the gluteal cleft for midline pits and sinus tracts.
  • Evaluate for an acute pilonidal abscess and/or cellulitis, e.g., soft tissue POCUS
  • Perform an anorectal examination to rule out anorectal abscess and fistula.
• Imaging (e.g., CT, US) is typically reserved for complex pilonidal disease to determine the extent of disease and rule out complications.

Pilonidal abscesses are located near the upper gluteal cleft, whereas perirectal abscesses are located near the anus.

• Anal fistula (e.g., due to Crohn disease)
• Hidradenitis suppurativa
• Anorectal abscess
• Sacrococcygeal teratoma
• Granulomas (e.g., syphilis, tuberculosis)

The differential diagnoses listed here are not exhaustive.

Approach ^[5][6][9]

• All patients: lifestyle modifications to prevent recurrence
  • Local hygiene
  • Hair removal (e.g., laser epilation) ^[10][11]
  • Avoidance of tight-fitting clothes and prolonged periods of sitting
• Acute pilonidal abscess: : incision and drainage with or without antibiotic treatment
• Chronic or recurrent pilonidal disease: definitive management with minimally invasive and/or surgical treatment

Acute pilonidal abscess ^[5][6][9]

• All patients
  • Manage acute pain with NSAIDs.
  • Encourage symptomatic management, e.g., sitz baths, warm compresses
  • Consider antibiotics. (See “Antibiotics for purulent SSTIs.”) ^[9][12][13]
• Simple abscess: Perform incision and drainage.
  • Avoid making an incision that crosses the midline. ^[8]
  • Consider packing the wound to allow for secondary wound closure. ^[14]
  • Refer to surgery for definitive pilonidal cyst management.
• Complicated abscess (e.g., deep, large, multiple sinus tracts): Consult surgery.

Do not perform incision and drainge in the absence of fluctuance: Premature incision before abscess formation may cause extension of the infectious process. ^[8]

Recurrent or chronic pilonidal disease ^[5][6][9]

• Refer to surgery for definitive management.
• Treatment options include:
  • Minimally invasive procedures, e.g., phenol or fibrin glue application to cyst and sinus tracts, sinusectomy
  • Excision with primary closure, e.g., Karydakis flap, Bascom cleft-lift ^[15]
  • Excision with secondary wound closure, with or without marsupialization ^[16]

• Wound dehiscence
• Recurrence
• Fistula
• Osteomyelitis
• Malignant transformation ^[6]

We list the most important complications. The selection is not exhaustive.