What antibiotics are used to treat peritonsillar abscess?

Antibiotic Treatment for Peritonsillar Abscess

For peritonsillar abscess, first-line antibiotic therapy should include clindamycin, trimethoprim-sulfamethoxazole, or doxycycline to cover both MRSA and anaerobic bacteria, in conjunction with surgical drainage which is essential for treatment success. 1

Microbiology and Antibiotic Selection

Peritonsillar abscesses are typically polymicrobial infections involving both aerobic and anaerobic bacteria:

• Common pathogens:

  • Streptococcus pyogenes (Group A Streptococcus)
  • Staphylococcus aureus (including MRSA)
  • Anaerobic bacteria
  • Less commonly: Haemophilus influenzae, Pseudomonas aeruginosa, Escherichia coli, and Enterococcus species 2

• First-line antibiotic options 1:

Antibiotic	Dosage	Coverage	Notes
Clindamycin	300-450 mg PO TID	MRSA, streptococci, anaerobes	Higher risk of C. difficile colitis
Trimethoprim-sulfamethoxazole	1-2 DS tablets PO BID	MRSA	Limited activity against β-hemolytic streptococci; avoid in pregnancy (3rd trimester) and children <2 months
Doxycycline	100 mg PO BID	MRSA	Limited streptococcal coverage; avoid in children <8 years and pregnancy

• Alternative options:
  • Penicillin: Effective for Streptococcus pyogenes but ineffective against Staphylococcus aureus due to resistance 2
  • Cephalosporins: Effective broad-spectrum coverage 3
  • Metronidazole: Often added for anaerobic coverage 3

Treatment Algorithm

1. Initial assessment:

   • Evaluate for signs of systemic infection (fever, malaise)
   • Assess for complications (airway obstruction, extension to deep neck tissues)
   • Consider imaging (ultrasound or CT) to confirm diagnosis in unclear cases 1, 4

2. Primary treatment:

   • Surgical drainage is essential - needle aspiration is the gold standard 3, 5
   • Aspirate at three points for optimal drainage 6
   • Collect specimen for culture and sensitivity testing 1

3. Antibiotic therapy:

   • Start empiric antibiotics immediately after drainage
   • For uncomplicated cases: oral antibiotics (see table above)
   • For severe infections or immunocompromised patients: parenteral therapy 1

4. Supportive care:

   • Hydration
   • Pain control
   • Consider corticosteroids to reduce symptoms and speed recovery 4

5. Follow-up:

   • Review patient's condition 2-3 days after initial treatment
   • If no improvement, consider:
     • Re-evaluation of diagnosis
     • Review of culture results
     • Alternative antibiotic regimen 1

Special Considerations

• Treatment failure: If symptoms persist beyond 7 days, diagnostic re-evaluation is warranted 1
• Recurrent infections: Consider interval tonsillectomy, especially with history of recurrent tonsillitis 6
• Complications: Monitor for airway obstruction, aspiration, or extension of infection into deep neck tissues 4

Pitfalls to Avoid

1. Relying on antibiotics alone: Surgical drainage is essential; antibiotics alone are insufficient 1
2. Using penicillin as monotherapy: While effective against Streptococcus pyogenes, it's ineffective against Staphylococcus aureus due to resistance 2
3. Delaying treatment: Prompt recognition and initiation of therapy are crucial to avoid serious complications 4
4. Inadequate follow-up: Patients should be reassessed within 2-3 days to ensure resolution of infection 1

Peritonsillar abscess management requires both appropriate surgical drainage and targeted antibiotic therapy to effectively treat the infection and prevent complications.