Treatment for Strep Throat
First-Line Antibiotic Therapy
For patients without penicillin allergy, prescribe oral amoxicillin 50 mg/kg once daily (maximum 1000 mg) or 25 mg/kg twice daily (maximum 500 mg per dose) for a full 10-day course. 1 Amoxicillin is preferred over penicillin V due to superior palatability, better compliance with once-daily dosing, and higher bacteriologic cure rates (79% vs 55% with lower-dose penicillin V). 2, 1
- Adult dosing: Amoxicillin 500 mg orally twice daily for 10 days, or penicillin V 500 mg orally twice daily for 10 days. 1
- Pediatric dosing: Amoxicillin 40–50 mg/kg/day divided twice daily (maximum 1000 mg per dose) for 10 days achieves 88% clinical cure versus 71% with conventional penicillin V dosing. 2
- No documented penicillin resistance exists worldwide among Group A Streptococcus, ensuring reliable efficacy. 3
When Oral Compliance Is Uncertain
- Intramuscular benzathine penicillin G as a single dose (600,000 units if <27 kg; 1,200,000 units if ≥27 kg) ensures complete treatment when adherence to oral therapy cannot be guaranteed. 1
Treatment for Penicillin-Allergic Patients
Step 1: Determine the Type of Allergic Reaction
Immediate/anaphylactic reactions (anaphylaxis, angioedema, respiratory distress, or urticaria occurring ≤1 hour after penicillin) carry up to 10% cross-reactivity with all β-lactam antibiotics, including cephalosporins—these patients must avoid all β-lactams. 3, 4
Non-immediate (delayed) reactions (mild rash or skin symptoms >1 hour after exposure) have only 0.1% cross-reactivity with first-generation cephalosporins, permitting their safe use. 3
For Non-Immediate Penicillin Allergy
Prescribe a first-generation cephalosporin: cephalexin 500 mg orally twice daily for 10 days (adults) or 20 mg/kg per dose twice daily (maximum 500 mg/dose) for 10 days (children). 1, 4 This recommendation is supported by strong, high-quality evidence demonstrating narrow-spectrum activity, proven efficacy, low cost, and essentially zero resistance. 3, 4
- Alternative: Cefadroxil 1 gram orally once daily for 10 days (adults) or 30 mg/kg once daily (maximum 1 gram) for 10 days (children). 1
For Immediate/Anaphylactic Penicillin Allergy
Prescribe clindamycin 300 mg orally three times daily for 10 days (adults) or 7 mg/kg per dose three times daily (maximum 300 mg/dose) for 10 days (children). 1, 3 Clindamycin is the preferred β-lactam-free alternative with only ~1% resistance among US Group A Streptococcus isolates and superior eradication rates in chronic carriers and treatment failures. 3, 4
- Alternative macrolide option: Azithromycin 500 mg orally once daily for 5 days (adults) or 12 mg/kg once daily (maximum 500 mg) for 5 days (children). 1, 3 However, macrolide resistance ranges from 5–8% in the United States and varies geographically, making clindamycin more reliable. 3, 4
- Another macrolide option: Clarithromycin 250 mg orally twice daily for 10 days (adults) or 7.5 mg/kg per dose twice daily (maximum 250 mg/dose) for 10 days (children), with similar resistance concerns as azithromycin. 3
Critical Treatment Duration Requirements
A full 10-day course is mandatory for all antibiotics except azithromycin to achieve maximal pharyngeal eradication of Group A Streptococcus and prevent acute rheumatic fever. 1, 3, 4 Shortening the course by even a few days leads to appreciable increases in treatment-failure rates and rheumatic-fever risk. 3, 4
- Azithromycin is the only exception, requiring only 5 days due to its prolonged tissue half-life. 1, 3
- Even if symptoms resolve within 3–4 days, the full 10-day course must be continued for all agents except azithromycin. 3
Treatment of Recurrent or Persistent Infections
For patients who fail initial therapy with amoxicillin or cephalexin, prescribe clindamycin because it achieves substantially higher eradication rates than penicillin or amoxicillin in chronic carriers and persistent infections. 3
- Pediatric dosing: Clindamycin 20–30 mg/kg/day divided three times daily (maximum 300 mg/dose) for 10 days. 1
- Adult dosing: Clindamycin 600 mg/day in 2–4 equally divided doses for 10 days. 1
- Alternative regimen: Amoxicillin-clavulanate 40 mg/kg/day (amoxicillin component) divided three times daily (maximum 2000 mg amoxicillin/day) for 10 days. 1, 3
Chronic Carrier Considerations
- Chronic pharyngeal carriers generally do not require treatment unless special circumstances exist (community outbreak of rheumatic fever, family history of rheumatic fever, or excessive family anxiety), because they rarely spread infection or develop complications. 3, 4
Adjunctive Symptomatic Treatment
- Offer acetaminophen or NSAIDs (e.g., ibuprofen) for moderate-to-severe sore throat, fever, or systemic discomfort. 1, 3
- Avoid aspirin in children due to the risk of Reye syndrome. 1, 3
- Corticosteroids are not recommended as adjunctive therapy for streptococcal pharyngitis. 3
Common Pitfalls to Avoid
- Do not prescribe cephalosporins to patients with immediate/anaphylactic penicillin reactions (anaphylaxis, angioedema, or immediate urticaria) due to the ~10% cross-reactivity risk. 1, 3, 4
- Do not shorten the antibiotic course below 10 days (except azithromycin's 5-day regimen), as this markedly increases treatment failure and rheumatic-fever risk. 1, 3, 4
- Do not order routine post-treatment throat cultures for asymptomatic patients who have completed therapy; reserve testing for special circumstances such as a history of rheumatic fever. 3, 4
- Do not prescribe trimethoprim-sulfamethoxazole (Bactrim) for strep throat, as sulfonamides fail to eradicate Group A Streptococcus in 20–25% of cases. 3