What is the recommended treatment for perianal abscesses?

Perianal Abscess Treatment

Prompt surgical incision and drainage is the cornerstone of treatment for all perianal abscesses and should never be delayed, as antibiotics alone are insufficient and will lead to treatment failure. 1

Timing of Surgical Intervention

• Emergency drainage (within hours) is mandatory for patients with sepsis, severe sepsis, septic shock, immunosuppression, diabetes mellitus, or diffuse cellulitis 1
• In the absence of these high-risk factors, surgical drainage should ideally be performed within 24 hours of diagnosis 1
• An undrained perianal abscess can expand into adjacent spaces and progress to generalized systemic infection 2

Surgical Technique

The primary goal is to drain the abscess expeditiously while keeping the incision as close as possible to the anal verge to minimize potential fistula length 1

Approach Based on Abscess Location:

• Perianal and ischioanal abscesses: drain via overlying skin 1
• Intersphincteric abscesses: drain via rectal lumen 1
• Supralevator abscesses: drain via rectal lumen or externally via skin 1

Technical Considerations:

• Large abscesses should be drained with multiple counter incisions rather than a single long incision, which creates step-off deformity and delays healing 2
• Complete drainage is essential, as inadequate drainage is associated with high recurrence rates (up to 44% with loculations) 1
• A minimally invasive approach using small incisions may be associated with better compliance and fewer complications than traditional large incisions 3

Management of Concomitant Fistulas

If an obvious fistula is identified during abscess drainage, perform fistulotomy only for low fistulas not involving sphincter muscle 1

• For fistulas involving any sphincter muscle, place a loose draining seton rather than performing fistulotomy 1
• Treating the fistula at the time of abscess drainage significantly reduces recurrence (RR=0.13,95% CI 0.07-0.24) without statistically significant risk of incontinence at one year 4
• For high perianal abscesses, incision with seton drainage demonstrates higher cure rates, shorter wound healing time, lower VAS scores, and lower recurrence rates compared to simple incision and drainage 5

Antibiotic Therapy

Antibiotics are NOT routinely indicated after adequate surgical drainage in immunocompetent patients without systemic infection 1

Indications for Antibiotic Use:

• Sepsis and/or surrounding soft tissue infection/cellulitis 1
• Immunocompromised patients 1
• Disturbances of immune response or high-risk patients 1
• Incomplete source control or abscess with significant cellulitis 2

Antibiotic Selection When Indicated:

• Use empiric broad-spectrum antibiotic therapy with coverage of Gram-positive, Gram-negative, and anaerobic bacteria 2
• These abscesses are frequently polymicrobial in origin 2

Post-Operative Care

• Wound packing after abscess drainage is controversial and not routinely recommended, as evidence suggests it may be costly and painful without adding benefit to healing 1
• Routine imaging after incision and drainage is not required 1
• Consider follow-up imaging only in cases of recurrence, suspected inflammatory bowel disease, or evidence of fistula or non-healing wound 1

Common Pitfalls and Risk Factors for Recurrence

Risk Factors to Recognize:

• Inadequate drainage is the most preventable cause of recurrence 1
• Loculations (recurrence rate up to 44%) 1
• Horseshoe-type abscess 1
• Delayed time from disease onset to incision 1

Special Considerations:

• If perianal Crohn's disease is suspected, perform endoscopic assessment of the rectum, as proctitis predicts persistent non-healed fistula tracts and higher proctectomy rates 1
• Always consider foreign body impaction as an unusual cause, which requires removal along with drainage for definitive cure 6
• For smaller abscesses in patients without fever or elevated inflammatory markers, bedside drainage in the emergency department is safe and effective, with significantly shorter waiting times (2.13 vs 10.41 hours) and lower recurrence rates compared to operating room drainage 7