Treatment of Perianal Abscess
The primary treatment for perianal abscesses is immediate surgical incision and drainage, with antibiotic therapy indicated only in specific circumstances such as systemic infection, immunocompromised patients, incomplete source control, or significant cellulitis. 1
Surgical Management
Primary Treatment
- Immediate surgical incision and drainage is mandatory for all perianal abscesses 1
- For large abscesses, multiple counter incisions are preferred over a single long incision to prevent step-off deformity and delayed wound healing 1
- The goal is to drain the abscess expeditiously, identify any fistula tract, and either proceed with primary fistulotomy or place a draining seton 1
Procedural Considerations
- Bedside drainage in the emergency department may be appropriate for small, uncomplicated abscesses, which can significantly shorten waiting time without increasing long-term complications 2
- Operating room drainage is preferred for larger abscesses, those with systemic symptoms, or suspected complex anatomy 2
- During the procedure, examination for a potential fistula tract should be performed, as approximately 7.3% of patients may have synchronous fistulas identified during OR drainage 2
Antibiotic Therapy
Antibiotics are not routinely required for uncomplicated perianal abscesses with adequate drainage, but are indicated in the following situations 1:
- Presence of systemic signs of infection
- Immunocompromised patients
- Incomplete source control
- Significant surrounding cellulitis
When antibiotics are indicated:
- Use empiric broad-spectrum coverage for Gram-positive, Gram-negative, and anaerobic bacteria 1
- For immunocompetent patients with adequate source control, administer for 4 days 3
- For immunocompromised or critically ill patients, continue for up to 7 days based on clinical response 3
- Consider MRSA coverage in areas with high prevalence 1, 3
Post-Drainage Management
Wound Care
- Allow the wound to heal by secondary intention 3
- Clean with warm water/saline 2-3 times daily 3
- Sitz baths are recommended to keep the area clean 3
- Use non-adherent absorbent dressings; consider alginate or hydrofiber dressings for deeper wounds 3
Follow-up
- First follow-up within 48-72 hours after packing removal 3
- Subsequent follow-ups every 1-2 weeks until complete healing 3
- Monitor for signs of:
- Recurrent abscess formation
- Development of fistula
- Delayed healing
- Signs of infection
Special Considerations
Fistula Management
- If a fistula is identified during drainage, consider seton placement or fistulotomy 1, 4
- Meta-analysis shows significant reduction in recurrence when fistula is treated at the time of abscess drainage (RR=0.13,95% CI 0.07-0.24) 4
- Risk of incontinence following fistula surgery with abscess drainage is not statistically significant (RR 3.06,95% CI 0.7-13.45) 4
Crohn's Disease
- Patients with Crohn's disease have higher rates of perianal abscess formation and recurrence 5
- Seton or catheter drainage is particularly effective in these patients 5
- Fecal diversion (stoma) significantly reduces abscess recurrence (13% vs 60% after two years) 5
Pitfalls and Caveats
- Do not attempt needle aspiration as primary treatment - a randomized controlled trial showed 41% recurrence rate with needle aspiration compared to 15% with incision drainage 6
- Do not delay surgical drainage, as this can lead to expansion into adjacent spaces and progression to systemic infection 1
- Avoid long incisions that can create step-off deformities and delay wound healing 1
- Internal packing of abscess cavities after drainage remains controversial with limited evidence on its benefit for healing time 7
- Patients with superficial fistulas have lower recurrence rates compared to those with transsphincteric or ischiorectal fistulas 5
By following these evidence-based recommendations, perianal abscesses can be effectively managed with minimal complications and reduced risk of recurrence.