Pilonidal Abscess

Pilonidal abscess is an acute infection of the sacrococcygeal region resulting from hair follicle obstruction and foreign-body reaction in the natal cleft, predominantly affecting young adults (peak incidence ~19–21 years), with a male predominance of at least 2:1. [1-2] The following figure outlines a hierarchical management algorithm for pilonidal disease:

• Onset and progression: Rapid onset of pain in the gluteal cleft, often over hours to days; ask about prior episodes or chronic intermittent drainage [1]
• Symptom characterization: Throbbing sacrococcygeal pain worsened by sitting, walking, or pressure; may report spontaneous purulent or serosanguinous drainage [1]
• Triggers: Prolonged sitting (long drives, desk work), recent trauma to the area, increased sweating
• Associated symptoms: Foul-smelling discharge, bleeding from the site, fever/chills (suggests systemic involvement)
• Important negatives: Perianal symptoms (fistula vs. pilonidal), groin involvement (hidradenitis), GI symptoms (Crohn's disease), weight loss

• Fever, tachycardia, hypotension → concern for sepsis/necrotizing soft tissue infection [3]
• Rapidly expanding cellulitis, crepitus, or skin necrosis → necrotizing fasciitis until proven otherwise
• SIRS criteria (temp >38°C or <36°C, HR >90, RR >24, WBC >12,000 or <4,000) → indication for antibiotics and possible admission [3]
• Immunocompromised patients (diabetes, HIV, chemotherapy) → higher risk of complicated infection
• Suspicious skin lesions overlying chronic disease → biopsy to rule out rare malignant degeneration (squamous cell carcinoma) [4]

• Antibiotics are NOT routinely required after uncomplicated I&D of a pilonidal abscess. The ASCRS guidelines emphasize drainage as the mainstay [4]
• Indications for antibiotics: SIRS, significant surrounding cellulitis, immunocompromised host, failed initial treatment [3]
  • TMP-SMX (1 DS tab BID × 7–10 days) or clindamycin (300–450 mg TID × 7–10 days) for MRSA coverage [5]
  • Amoxicillin-clavulanate if mixed flora suspected (anaerobic coverage)
• Needle aspiration + empirical antibiotics (covering aerobes and anaerobes) is an emerging alternative to I&D in select non-septic patients, with 95% success in one prospective cohort [6]
• Perioperative prophylaxis for elective excision: mixed evidence; single-dose cefazolin + metronidazole has not shown clear benefit [4]
• Avoid: No specific contraindicated medications, but be cautious with clindamycin in patients with C. difficile history

• No specific acute dietary modifications are required
• Weight management is important for long-term recurrence prevention, as obesity is a significant risk factor [1][7]
• Adequate hydration and nutrition support wound healing post-I&D

• Constitutional: Fever, chills, malaise (systemic infection)
• GI: Perianal drainage, diarrhea, bloody stools (Crohn's disease with perianal fistula)
• Skin: Other abscesses, axillary/groin nodules (hidradenitis suppurativa), chronic wounds
• Musculoskeletal: Sacral/coccygeal pain (osteomyelitis in chronic/neglected cases)
• Endocrine: Polyuria, polydipsia (undiagnosed diabetes increasing infection risk)

• Family history of pilonidal disease is associated with increased overall incidence and earlier onset [1]
• Family history of hidradenitis suppurativa or inflammatory bowel disease
• Occupational history: Sedentary occupation (truck drivers, office workers) is a well-established risk factor [2]
• Social context: Impact on school/work attendance, sports participation, and social activities — significant psychosocial burden especially in adolescents [1]

• Male sex (≥2:1 male-to-female ratio) [1]
• Young adulthood (peak incidence late teens to early 20s) [1]
• Obesity [2][7]
• Hirsutism / excessive body hair [1][7]
• Sedentary lifestyle / prolonged sitting [2]
• Deep natal cleft anatomy [1]
• Local trauma or chronic irritation to the sacrococcygeal area [7]
• Family history of pilonidal disease [1]
• Prior pilonidal disease — recurrence rate 15–40% after simple I&D [4]

• Perianal/anorectal abscess or fistula — more caudal location, closer to the anal verge; perform thorough anorectal exam [4]
• Hidradenitis suppurativa — recurrent abscesses in apocrine gland-bearing areas (axillae, groin, gluteal); look for bilateral/multifocal involvement [4][8]
• Infected skin furuncle/carbuncle — no midline pits, no sinus tracts [4]
• Dermoid cyst — congenital, midline, may be deeper [8]
• Crohn's disease with perianal fistula — GI symptoms, complex fistulous disease [4]
• Infectious etiologies (rare): Tuberculosis, syphilis, actinomycosis [4]
• Malignant degeneration (squamous cell carcinoma) — extremely rare, consider in chronic/recurrent disease, especially immunosuppressed [4]

• Prior pilonidal episodes — number, treatments received, time to healing, recurrence pattern
• Previous I&D or surgical excision — type of procedure, wound closure method, complications
• Diabetes mellitus — impaired wound healing, increased infection risk
• Immunosuppression (medications, HIV) — higher complication risk
• Inflammatory bowel disease — particularly Crohn's with perianal manifestations
• Smoking — impairs wound healing

• Vital signs: Temperature, heart rate, blood pressure (assess for SIRS/sepsis)
• Inspection of natal cleft:
  • Characteristic midline pits — pathognomonic for pilonidal disease; almost always present [4]
  • Erythema, induration, fluctuance typically lateral and/or superior to midline [1]
  • Active purulent or serosanguinous drainage
  • Secondary openings off-midline with granulation tissue (chronic disease) [1]
• Palpation: Fluctuance (abscess ready for drainage), tenderness, induration extent, crepitus (concerning for necrotizing infection)
• Anorectal exam: Essential to rule out concomitant fistulous disease, perianal abscess, or Crohn's-related pathology [4]
• Assess surrounding skin: Extent of cellulitis, skin necrosis, satellite lesions

• Routine labs are generally unnecessary for uncomplicated pilonidal abscess
• Obtain if systemic illness suspected:
  • CBC with differential (leukocytosis)
  • BMP (renal function if considering antibiotics)
  • Blood cultures (if septic)
  • Lactate (if concern for sepsis)
  • Blood glucose / HbA1c (if diabetes suspected)
• Wound culture: Gram stain and culture of purulent drainage are recommended for abscesses, though treatment without these studies is reasonable in typical cases [3]
  • Staphylococcus aureus

• Imaging is generally unnecessary — diagnosis is clinical based on history and physical exam [4]
• Ultrasound (point-of-care): Useful when diagnosis is uncertain, to confirm fluctuance, delineate abscess cavity size, or guide drainage [9]
• MRI: Reserved for complex or recurrent disease to map sinus tracts, rule out deep extension, or differentiate from perianal fistula
• CT: Rarely needed; consider if concern for deep space infection or necrotizing soft tissue infection

• No validated scoring systems specific to pilonidal abscess severity; no universally accepted classification system exists [8]
• Point-of-care ultrasound (POCUS): Valuable for confirming abscess vs. cellulitis and guiding I&D [9]
• Biopsy: Indicated if skin lesions have a suspicious appearance in chronic/recurrent disease to rule out malignancy [4]
• Fistulography or MRI fistula protocol: For complex recurrent disease with suspected extensive sinus tracts

• Not routinely indicated for pilonidal abscess
• Obtain if:
  • Sepsis or SIRS present (tachycardia evaluation, septic cardiomyopathy)
  • Pre-procedural assessment for patients requiring operative management under general anesthesia
  • Significant comorbidities warranting cardiac evaluation

Pilonidal abscess is a clinical diagnosis characterized by a painful, fluctuant mass in the sacrococcygeal region with characteristic midline pits in the natal cleft. [4] Approximately 50% of patients with pilonidal disease present with an acute infection. [1] The condition is acquired, resulting from hair follicle obstruction and foreign-body reaction, and is a chronic disease process with intermittent flares and quiescent periods. [1]

Severity stratification

• Uncomplicated: Localized abscess, no SIRS, immunocompetent → ED I&D and discharge
• Moderate: Significant cellulitis, SIRS criteria met → I&D + antibiotics, close follow-up
• Severe: Sepsis, necrotizing features, immunocompromised → emergent drainage, IV antibiotics, admission

Recurrence is the hallmark challenge: simple I&D carries a 15–40% recurrence rate, and overall recurrence across all treatments ranges from 0–66% with ~80% of recurrences occurring within the first year. [1][4]

Initial Stabilization (ED)

• Incision and drainage is the definitive ED treatment — strong recommendation (ASCRS Grade 1B) [4]
  • Incise over the point of maximal fluctuance, lateral to midline pits
  • Express pus, break up loculations, remove hair and debris
  • Unroofing with curettage (lay open technique) is a one-step option that significantly reduces recurrence (10% vs. 54%) and improves healing at 10 weeks (96% vs. 79%) compared to simple I&D alone [4]
• Needle aspiration + oral antibiotics is an alternative in select non-septic, non-immunocompromised patients without skin necrosis — 95% success rate in converting to elective procedure [6]

Wound Care

• Routine packing is likely unnecessary — contemporary evidence for cutaneous abscesses shows no outcome advantage with packing, and it increases pain [10]
• Simple dressing changes; wound heals by secondary intention
• Sitz baths for comfort and hygiene

Antibiotics

• Not routinely needed post-I&D for uncomplicated abscess [3-4]
• If indicated (SIRS, cellulitis, immunocompromised): TMP-SMX DS BID or clindamycin 300–450 mg TID × 7–10 days [5]

Recurrence Prevention

• Improved hygiene: Regular cleaning of natal cleft, chlorhexidine washes [1]
• Hair removal: Weekly shaving or laser epilation of the gluteal cleft area [1][7]
• Weight loss if obese
• Avoid prolonged sitting; use cushions if sedentary occupation

Discharge criteria (majority of patients)

• Uncomplicated abscess successfully drained
• No SIRS/sepsis
• Tolerating PO, adequate pain control
• Reliable follow-up available

Admission criteria

• Sepsis or hemodynamic instability
• Necrotizing soft tissue infection
• Failed outpatient management
• Significant immunocompromise with complicated infection
• Need for operative drainage under general anesthesia (large/complex abscess)

Observation

Specialist consultation

• General surgery or colorectal surgery referral for all patients post-I&D to discuss definitive management and recurrence prevention [4]
• Urgent surgical consultation if concern for necrotizing infection or complex disease

Follow-up timing

• 48–72 hours for wound check (primary care or surgery)
• Surgical consultation within 2–4 weeks for discussion of definitive management if recurrent or chronic disease [6]

Return precautions — instruct patients to return immediately for:

• Fever >38°C (100.4°F)
• Worsening pain, swelling, or redness despite drainage
• Red streaking from the wound
• Foul-smelling drainage or inability to care for wound
• Dizziness, lightheadedness, or feeling generally unwell

Patient counseling

• Pilonidal disease is chronic with high recurrence rates — this is not a one-time problem [1]
• Emphasize hygiene, hair removal, and weight management as modifiable factors [1]
• Expected recovery: wound healing by secondary intention takes 4–10 weeks depending on cavity size
• Avoid prolonged sitting and strenuous activity until wound healed
• Definitive surgical options (Karydakis flap, Bascom cleft lift, excision with off-midline closure) should be discussed with a surgeon if disease recurs, as these offer lower long-term recurrence rates [4][7][11]

1. Management of Pilonidal Disease: A Review. — Gil LA, Deans KJ, Minneci PC. JAMA Surgery. 2023.

2. Dressings and Topical Agents for the Management of Open Wounds After Surgical Treatment for Sacrococcygeal Pilonidal Sinus. — Herrod PJ, Doleman B, Hardy EJ, et al. The Cochrane Database of Systematic Reviews. 2022.

3. Practice Guidelines for the Diagnosis and Management of Skin and Soft Tissue Infections: 2014 Update by the Infectious Diseases Society of America. — Stevens DL, Bisno AL, Chambers HF, et al. Clinical Infectious Diseases : An Official Publication of the Infectious Diseases Society of America. 2014.

4. The American Society of Colon and Rectal Surgeons' Clinical Practice Guidelines for the Management of Pilonidal Disease. — Johnson EK, Vogel JD, Cowan ML, Feingold DL, Steele SR. Diseases of the Colon and Rectum. 2019.

5. A Placebo-Controlled Trial of Antibiotics for Smaller Skin Abscesses. — Daum RS, Miller LG, Immergluck L, et al. The New England Journal of Medicine. 2017.

6. Converting Emergency Pilonidal Abscess Into an Elective Procedure. — Hussain ZI, Aghahoseini A, Alexander D. Diseases of the Colon and Rectum. 2012.

7. Pilonidal Disease. — O'Guinn ML, Nguyen ML, Raman S, Lin M. The Surgical Clinics of North America. 2026.

8. International Society of Laser Proctology Position Paper on SiLaC and EPSiT/­SiLaC in the Management of Pilonidal Sinus Disease. — Ouali M, Martin-Martin GP, Avdicausevic S, et al. Lasers in Surgery and Medicine. 2025.

9. Abscess Management: An Evidence-Based Review for Emergency Medicine Clinicians. — Menegas S, Moayedi S, Torres M. The Journal of Emergency Medicine. 2021.

10. Beyond the Knife: A Contemporary Review of Subcutaneous Abscesses. — Mersal M, Embaby O, Ayyad M, et al. ANZ Journal of Surgery. 2025.

11. Midline and Off-Midline Wound Closure Methods After Surgical Treatment for Pilonidal Sinus. — Cai Z, Zhao Z, Ma Q, et al. The Cochrane Database of Systematic Reviews. 2024.