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Pilonidal Disease

BASICS

  • Definition: Abscess or sinus tract in the upper natal (gluteal) cleft
  • Synonym: Jeep disease

EPIDEMIOLOGY

  • Incidence: 16–26 per 100,000/year
  • Sex: Male > female (3–4:1), surgical procedures show 4:1, but incidence data up to 10:1
  • Age: Most common 2nd–3rd decade; rare >45 years
  • Ethnicity: Whites > Blacks > Asians

ETIOLOGY & PATHOPHYSIOLOGY

  • Pathogenesis: "Nest of hair"; hair and debris drawn into the cleft → cyst formation
  • Mechanisms:
  • Hair insertion via movement/friction (50%)
  • Follicular occlusion and pore blockage (50%)
  • Infection: Polymicrobial (enteric flora common)
  • Genetic/structural: Congenital dimple, spina bifida occulta, follicular-occluding tetrad (acne conglobata, dissecting cellulitis, hidradenitis suppurativa, pilonidal)

RISK FACTORS

  • Sedentary lifestyle/prolonged sitting
  • Excess body hair
  • Obesity/increased fold thickness
  • Congenital natal dimple
  • Coccygeal trauma

PREVENTION

  • Weight loss
  • Trim gluteal cleft hair weekly
  • Good hygiene
  • Prevent ingrown hair/follicular blockage

DIAGNOSIS

History

  • Presentations:
  • Asymptomatic: painless cyst/sinus
  • Acute abscess: severe pain, swelling, ± drainage
  • Chronic abscess: persistent drainage from sinus tract

Physical Exam

  • Inflamed cystic mass, often with drainage or sinus pits, sometimes visible hair debris
  • ± cellulitis of surrounding tissues

Differential Diagnosis

  • Furunculosis, folliculitis
  • Hidradenitis suppurativa
  • Anal fistula
  • Perirectal abscess
  • Crohn disease

Diagnostic Tests

  • Clinical diagnosis is typical
  • CBC/wound culture only if severe infection or significant cellulitis
  • Imaging (US/MRI) only if diagnosis uncertain or perirectal abscess suspected

TREATMENT

General Measures

  • Shave/trim area, remove hair weekly
  • No surgical treatment needed for asymptomatic cyst

Medication

  • Antibiotics: Not indicated unless significant cellulitis; empiric choices: cefazolin + metronidazole, or amoxicillin-clavulanate

Procedures & Surgery

  • I&D: for abscess, minimal packing to allow drainage (overpacking not recommended)
  • Adjuncts: Negative pressure wound therapy, laser epilation, phenol infusion for recurrence
  • Definitive Surgery: Six levels of care based on recurrence/severity:
  • I&D with curettage, hair removal
  • Pit picking (midline excision for lateral sinus drainage)
  • Pilonidal cystotomy
  • Marsupialization
  • Off-midline excision/closure (cleft lift, modified Karydakis procedure) preferred over midline closure
  • Endoscopic sinus treatment (EPSiT), fibrin glue

Referral

  • Frequent dressing changes not feasible
  • Recurrent disease post I&D
  • Complex, multiple sinus tracts

ONGOING CARE

  • Dressing changes post I&D; monitor for fever/cellulitis
  • Patient education: Daily brisk washing, weekly hair removal, avoid sitting for prolonged periods
  • Monitor: Wound for healing and recurrence

PROGNOSIS

  • Simple I&D: 55% failure rate; median healing ~5 weeks
  • Extensive excisions: longer healing, possible hospital stay
  • Complications: Rare malignant degeneration if chronic/untreated

ICD-10 CODES

  • L05.91 Pilonidal cyst without abscess
  • L05.92 Pilonidal sinus without abscess
  • L05.01 Pilonidal cyst with abscess

CLINICAL PEARLS

  • Avoid prolonged sitting
  • Trim hair weekly in gluteal cleft
  • Refer recurrent/complex disease for surgical management
  • Most patients do not require antibiotics unless cellulitis present