Treatment of Group A Streptococcus (GAS) Pharyngitis in Adolescents
Penicillin or amoxicillin for 10 days is the first-line treatment for adolescents with confirmed GAS pharyngitis, with amoxicillin preferred due to better compliance and equal efficacy. 1, 2
First-Line Antibiotic Therapy
For adolescents without penicillin allergy:
- Oral amoxicillin is the preferred first-line agent at 50 mg/kg once daily (maximum 1,000 mg) or 25 mg/kg twice daily (maximum 500 mg per dose) for 10 days 2, 3
- Oral penicillin V is an equally effective alternative at 250 mg four times daily or 500 mg twice daily for 10 days 2, 4
- Intramuscular benzathine penicillin G 1,200,000 units as a single dose should be used if compliance with oral therapy is questionable 2
The 10-day duration is essential to achieve maximal pharyngeal eradication and prevent acute rheumatic fever, which remains the primary goal of treatment 1, 3. Penicillin and amoxicillin are recommended based on their narrow spectrum of activity, proven efficacy, infrequency of adverse reactions, and modest cost 1.
Treatment for Penicillin-Allergic Adolescents
The choice of alternative antibiotic depends on the type of penicillin allergy:
Non-Immediate (Non-Anaphylactic) Penicillin Allergy:
- First-generation cephalosporins are the preferred alternatives 1, 5
- Cephalexin 500 mg orally twice daily for 10 days 5
- Cefadroxil 30 mg/kg once daily (maximum 1 gram) for 10 days 5
- Cross-reactivity risk is only 0.1% in patients with non-severe, delayed penicillin reactions 5
Immediate/Anaphylactic Penicillin Allergy:
All beta-lactam antibiotics must be avoided due to up to 10% cross-reactivity risk 1, 5
Preferred alternatives include:
- Clindamycin 300 mg orally three times daily for 10 days (preferred due to ~1% resistance rate in the US) 5
- Azithromycin 500 mg orally once daily for 5 days (only antibiotic requiring just 5 days due to prolonged tissue half-life) 1, 5
- Clarithromycin 250 mg orally twice daily for 10 days 1
Critical consideration: Macrolide resistance among GAS is approximately 5-8% in the United States, making clindamycin more reliable in areas with high resistance 5. Clindamycin demonstrates high efficacy even in chronic carriers 5.
Diagnostic Confirmation Required
Testing is mandatory before treatment in adolescents:
- Perform rapid antigen detection test (RADT) on throat swab 1
- Positive RADT is diagnostic and requires no backup culture due to high specificity 1
- Negative RADT must be backed up by throat culture in children and adolescents to ensure maximal sensitivity 1
- Do not test or treat if clinical features strongly suggest viral etiology (cough, rhinorrhea, hoarseness, oral ulcers) 1, 6
Adjunctive Symptomatic Therapy
For moderate to severe symptoms or high fever:
- Acetaminophen or NSAIDs (such as ibuprofen) should be used as adjuncts to antibiotics 1, 2
- Aspirin must be avoided in adolescents due to Reye syndrome risk 1, 2
- Corticosteroids are not recommended as adjunctive therapy 1
Critical Pitfalls to Avoid
Do not shorten antibiotic courses below 10 days (except azithromycin's 5-day regimen), as this dramatically increases treatment failure rates and risk of acute rheumatic fever 5. Even a few days' reduction results in appreciable increases in treatment failure 5.
Do not prescribe cephalosporins to patients with immediate/anaphylactic penicillin reactions due to the 10% cross-reactivity risk 1, 5. This includes patients with history of anaphylaxis, angioedema, respiratory distress, or urticaria occurring within 1 hour of penicillin administration 5.
Do not use trimethoprim-sulfamethoxazole (Bactrim) for GAS pharyngitis due to high resistance rates and lack of efficacy 5.
Do not perform routine post-treatment throat cultures for asymptomatic patients who have completed therapy 1, 2. Follow-up testing should only be considered in special circumstances, such as patients with history of rheumatic fever 5.
Do not treat asymptomatic household contacts unless they develop symptoms 1.
Special Considerations for Recurrent Infections
For adolescents with recurrent GAS pharyngitis, consider that they may be chronic pharyngeal carriers experiencing repeated viral infections rather than true recurrent streptococcal infections 1. Chronic carriers generally do not require antimicrobial therapy as they are unlikely to spread GAS and are at little risk for complications 5.
If retreatment is necessary, options include the same agent used initially, intramuscular benzathine penicillin G if compliance is questionable, or clindamycin for chronic carriers 2.