What is the treatment for an abscess with surrounding cellulitis?

Treatment of Abscess with Surrounding Cellulitis

For an abscess with surrounding cellulitis, incision and drainage is the primary treatment, with adjunctive antibiotic therapy required due to the presence of significant cellulitis extending beyond the abscess borders. 1

Primary Treatment Approach

Surgical Drainage

• Incision and drainage must be performed as the cornerstone of treatment, as purulent collections require mechanical drainage rather than antibiotics alone 1
• The incision should provide adequate drainage while minimizing potential complications—for perianal abscesses, keep the incision as close as possible to the anal verge to minimize fistula tract length 1
• Timing of drainage should be emergent if systemic signs of infection, sepsis, immunosuppression, diabetes, or diffuse cellulitis are present 1
• In the absence of these factors, drainage should ideally occur within 24 hours 1

Antibiotic Therapy Indications

The presence of significant cellulitis surrounding the abscess is a specific indication for adjunctive antibiotics, distinguishing this from simple abscesses that require drainage alone 1

Additional indications for antibiotics include:

• Systemic signs of infection (fever, tachycardia, hypotension) 1
• Immunocompromised patients 1
• Incomplete source control 1
• Diabetes mellitus 1

Antibiotic Selection

For Typical Cases (Non-Complex Abscesses)

• Oral beta-lactams are appropriate for mild-to-moderate cases: cephalexin, dicloxacillin, amoxicillin-clavulanate, or clindamycin 1
• Clindamycin 300-450 mg every 6 hours orally for adults is effective and covers both streptococci and MRSA 2, 3
• TMP-SMX is an alternative option, though it lacks streptococcal coverage and should be combined with a beta-lactam if streptococci are suspected 3

For Complex Abscesses (Perianal, Perirectal, or Severe Infections)

• Empiric broad-spectrum coverage of Gram-positive, Gram-negative, and anaerobic bacteria is required 1
• Parenteral options include ampicillin-sulbactam 3g IV every 6 hours 4
• For penicillin allergy: clindamycin 600mg IV three times daily 4, 2
• For severe infections with systemic toxicity: vancomycin plus piperacillin-tazobactam or a carbapenem 4

MRSA Considerations

• MRSA is uncommon in typical cellulitis but common in abscesses (49% prevalence in one study) 1, 3
• Coverage for MRSA should be considered when there is purulent drainage, penetrating trauma (especially IV drug use), or concurrent MRSA infection elsewhere 1
• Clindamycin provides MRSA coverage and was superior to TMP-SMX in preventing recurrent infections (6.8% vs 13.5% at 1 month) 3

Duration of Treatment

• 5-7 days of antibiotic therapy is typically sufficient if clinical improvement occurs 1, 4
• For more severe infections, extend to 7-14 days depending on clinical response 4
• Continue antibiotics until resolution of systemic symptoms and significant improvement in local signs 4

Critical Distinctions

The terminology matters clinically: "cellulitis" refers to diffuse spreading infection requiring antibiotics, while inflammation surrounding a purulent collection should be termed "abscess with surrounding inflammation" to emphasize that drainage is the primary treatment 1

When Antibiotics Are NOT Needed

• Simple abscesses without surrounding cellulitis in immunocompetent patients require drainage alone 1, 5, 6
• The erythema and induration should be limited only to the defined area of the abscess without extension beyond its borders 1

Common Pitfalls

• Failing to drain the abscess adequately: Incomplete drainage is a major risk factor for recurrence (up to 44% recurrence rate) 1
• Using antibiotics alone without drainage for purulent collections—this will fail 1
• Assuming all surrounding erythema represents cellulitis requiring antibiotics—some inflammation is expected around any abscess 1
• Unnecessary wound packing: Evidence does not support routine packing after drainage, and it increases pain and healthcare costs 1

Hospitalization Criteria

Admit patients with:

• Systemic inflammatory response syndrome (SIRS) or sepsis 4
• Hemodynamic instability or altered mental status 4
• Severe immunocompromise 1, 4
• Concern for deeper or necrotizing infection 1
• Poor adherence to outpatient therapy 1

Follow-up

• Surgical re-evaluation is warranted if no improvement occurs within 48-72 hours 4
• Most patients can be managed as outpatients with close follow-up 5