What antibiotics are recommended for streptococcal pharyngitis in a patient with a penicillin allergy?

Antibiotic Treatment for Streptococcal Pharyngitis in Patients with Penicillin Allergy

For patients with streptococcal pharyngitis who have penicillin allergy, first-generation cephalosporins are recommended for those without anaphylactic reactions, while clindamycin, clarithromycin, or azithromycin are recommended for those with severe/immediate penicillin allergy. 1, 2

Treatment Algorithm Based on Type of Penicillin Allergy

Non-Anaphylactic Penicillin Allergy

• First-generation cephalosporins are the preferred first-line alternatives for patients without immediate hypersensitivity to penicillin 1, 2
• Recommended options include:
  • Cephalexin: 20 mg/kg per dose twice daily for 10 days 2
  • Cefadroxil: 30 mg/kg once daily for 10 days 2

Immediate/Anaphylactic Penicillin Allergy

• Patients with immediate hypersensitivity to penicillin should avoid cephalosporins due to potential cross-reactivity (up to 10%) 2
• Recommended alternatives include:

1. Clindamycin

   • Dosage: 7 mg/kg per dose three times daily (maximum = 300 mg per dose) for 10 days 2
   • Particularly effective for eradicating streptococci, even in chronic carriers 2
   • Low resistance rates (approximately 1% in the US) 2

2. Macrolides

   • Clarithromycin
     • Dosage: 7.5 mg/kg per dose twice daily (maximum = 250 mg per dose) for 10 days 2
   • Azithromycin
     • Dosage: 12 mg/kg once daily (maximum = 500 mg) for 5 days 2, 3
     • Only macrolide requiring a shorter course due to its prolonged tissue half-life 2, 4
   • Consider local resistance patterns when prescribing macrolides (5-8% resistance in the US) 2

Duration of Therapy

• Most antibiotics require a full 10-day course to achieve maximal pharyngeal eradication of Group A Streptococcus 1, 2
• Azithromycin is the exception, requiring only a 5-day course 1, 3, 4
• Shorter courses of other antibiotics may lead to treatment failure and complications 2

Efficacy Considerations

• First-generation cephalosporins have strong evidence for efficacy in non-anaphylactic penicillin-allergic patients 2, 5
• Clindamycin demonstrates high efficacy in eradicating streptococci 2
• Macrolides have moderate-quality evidence but carry concerns about resistance 2, 6
• A comparative study showed that 10 days of clarithromycin therapy (91% eradication) was more effective than 5 days of azithromycin therapy (82% eradication) 6

Adjunctive Therapy

• Acetaminophen or NSAIDs can be used for moderate to severe symptoms or high fever 2, 7
• Avoid aspirin in children due to the risk of Reye syndrome 2
• Corticosteroids are not recommended as adjunctive therapy 2
• Medicated throat lozenges used every two hours can provide symptomatic relief 7

Common Pitfalls to Avoid

• Assuming all penicillin-allergic patients cannot receive cephalosporins - only those with immediate/anaphylactic reactions should avoid them 2
• Prescribing shorter courses than recommended (except for azithromycin) 2
• Ignoring local resistance patterns when prescribing macrolides 2
• Routine post-treatment throat cultures are not recommended for asymptomatic patients who have completed therapy 2

Special Considerations

• For patients with recurrent streptococcal pharyngitis, clindamycin may be particularly effective due to its ability to eradicate the organism in chronic carriers 2
• In areas with high macrolide resistance, cephalosporins are preferred for patients without severe penicillin allergy 2