What is the best antibiotic (abx) for a peritonsillar abscess?

Antibiotic Treatment for Peritonsillar Abscess

For peritonsillar abscess, clindamycin is the best antibiotic choice due to its excellent coverage against both aerobic and anaerobic bacteria commonly found in these infections, particularly Streptococcus pyogenes and oral anaerobes. 1

Microbiology and Antibiotic Selection

Peritonsillar abscesses are typically polymicrobial infections with the following characteristics:

• Most commonly isolated organisms:
  • Streptococcus pyogenes (Group A Streptococcus)
  • Fusobacterium necrophorum
  • Staphylococcus aureus
  • Oral anaerobes 2, 3

First-line antibiotic options:

1. Clindamycin (300-450 mg orally every 8 hours for 10-14 days)

   • Provides excellent coverage against both streptococci and oral anaerobes
   • Active against both aerobic and anaerobic components of infection 1

2. Amoxicillin-clavulanate (875/125 mg twice daily)

   • Broad-spectrum coverage for mixed aerobic/anaerobic infections
   • Good alternative when clindamycin cannot be used 1

For patients with penicillin allergy or MRSA concerns:

• Clindamycin remains first choice if no resistance concerns
• Linezolid (600 mg orally twice daily) for suspected MRSA 4
• Metronidazole (500 mg every 8 hours) plus a macrolide for anaerobic coverage 1

Treatment Algorithm

1. Initial assessment:

   • Evaluate for systemic toxicity (fever, tachycardia)
   • Assess trismus, voice changes, and ability to swallow
   • Determine if outpatient management is appropriate 5

2. Drainage procedure:

   • Needle aspiration is the gold standard for both diagnosis and initial treatment 6
   • Incision and drainage for larger or recurrent abscesses

3. Antibiotic therapy:

   • Outpatient treatment: Clindamycin 300-450 mg orally every 8 hours for 10-14 days 1
   • Inpatient treatment: For severe cases with systemic symptoms:
     • Clindamycin + piperacillin-tazobactam IV
     • Alternative: ceftriaxone + metronidazole IV 1

4. Adjunctive therapy:

   • Corticosteroids to reduce inflammation and pain
   • Adequate hydration and pain control 7, 3

Special Considerations

• History of recurrent peritonsillar abscess: Consider tonsillectomy after resolution of acute infection 4
• Immunocompromised patients: Lower threshold for inpatient management with IV antibiotics
• Severe cases: Watch for complications including airway obstruction, extension to deep neck spaces, or sepsis 5

Pitfalls to Avoid

1. Inadequate drainage: Relying solely on antibiotics without proper drainage often leads to treatment failure
2. Inappropriate antibiotic selection: Using antibiotics without anaerobic coverage (like fluoroquinolones alone) may result in treatment failure 4
3. Delayed recognition of complications: Extension to parapharyngeal or retropharyngeal spaces requires immediate surgical intervention
4. Premature discontinuation of antibiotics: Complete the full course (10-14 days) even if symptoms improve quickly 1

Peritonsillar abscess management requires both appropriate drainage and targeted antibiotic therapy. While outpatient management with clindamycin is appropriate for most cases 7, patients with severe symptoms, inability to maintain oral hydration, or concerning complications should be managed as inpatients with IV antibiotics and close monitoring.