Treatment of Streptococcal Pharyngitis in Teenagers
For a teenager with confirmed Group A streptococcal pharyngitis by rapid antigen detection test or throat culture, prescribe oral penicillin V 500 mg 2-3 times daily for 10 days, or amoxicillin 50 mg/kg once daily (maximum 1 gram) for 10 days. 1
First-Line Treatment Regimens
The American Heart Association and Infectious Diseases Society of America establish penicillin as the definitive first-line agent based on proven efficacy in preventing acute rheumatic fever, narrow spectrum of activity, safety profile, and low cost. 1
Recommended penicillin dosing for adolescents ≥27 kg (60 lb):
- Penicillin V: 500 mg orally 2-3 times daily for 10 days 1
- Amoxicillin: 50 mg/kg once daily (maximum 1 gram) for 10 days 1
- Benzathine penicillin G: 1,200,000 units intramuscularly as a single dose 1
The 10-day duration is mandatory—shortening the course by even a few days significantly increases treatment failure rates and risk of rheumatic fever. 1, 2 Intramuscular benzathine penicillin G should be reserved for teenagers when compliance with oral therapy is questionable. 1
Penicillin-Allergic Patients
For non-anaphylactic penicillin allergy (e.g., rash):
- First-generation cephalosporin (such as cephalexin) for 10 days 1
For immediate-type hypersensitivity or anaphylaxis:
- Clindamycin: 20 mg/kg/day divided in 3 doses (maximum 1.8 g/day) for 10 days 1
- Azithromycin: 12 mg/kg once daily (maximum 500 mg) for 5 days 1
- Clarithromycin: 15 mg/kg/day divided twice daily (maximum 250 mg twice daily) for 10 days 1
Cephalosporins must be avoided in patients with immediate hypersensitivity reactions to penicillin due to approximately 10% cross-reactivity risk. 1
Treatment Goals and Timing
The primary objective is prevention of acute rheumatic fever, which remains achievable when treatment is initiated within 9 days of symptom onset. 1 Secondary goals include reducing symptom duration (typically to less than 24 hours), preventing suppurative complications (peritonsillar abscess, cervical lymphadenitis), and limiting transmission to close contacts. 1, 3
Critical Pitfalls to Avoid
Do not perform routine post-treatment testing in asymptomatic teenagers. Follow-up throat cultures or rapid tests are not indicated after completing appropriate antibiotic therapy, even if the patient was initially symptomatic. 1 A positive post-treatment test in an asymptomatic patient likely reflects chronic carrier status rather than treatment failure. 1
Do not test or treat asymptomatic household contacts. Up to 20-33% of household members may be asymptomatic Group A streptococcal carriers during winter and spring, but prophylactic treatment does not reduce subsequent infection rates. 1
Do not use sulfonamides, trimethoprim, tetracyclines, or fluoroquinolones—these agents are not effective against Group A streptococcus. 1
Do not shorten the antibiotic course. Even reducing a 10-day penicillin course by 2-3 days results in appreciably higher treatment failure rates. 1, 2 The only exception is azithromycin, which requires only 5 days due to prolonged tissue half-life. 1
Recurrent or Persistent Symptoms
If a teenager develops recurrent pharyngitis with positive testing shortly after completing treatment, consider several possibilities: chronic carrier state with intercurrent viral infection (most common), noncompliance with the original 10-day regimen, new infection from family or community contacts, or true treatment failure. 1
For multiple documented recurrent episodes, alternative regimens include:
- Clindamycin 20-30 mg/kg/day in 3 divided doses for 10 days 1
- Amoxicillin-clavulanate 40 mg/kg/day (amoxicillin component) in 3 divided doses for 10 days 1
- Benzathine penicillin G with rifampin 20 mg/kg/day for 4 days 1
Chronic carriers have Group A streptococci present without immunologic response, are at very low risk for complications including rheumatic fever, and do not require eradication attempts unless special circumstances exist (history of rheumatic fever, outbreak situations). 1