Treatment of Streptococcal Pharyngitis in a 15-Year-Old
Penicillin or amoxicillin for 10 days is the recommended first-line treatment for streptococcal pharyngitis in a 15-year-old due to their proven efficacy, narrow spectrum of activity, infrequent adverse reactions, and modest cost. 1
First-Line Treatment Options
- Oral penicillin V: For adolescents, 250 mg four times daily or 500 mg twice daily for 10 days 1
- Amoxicillin: 50 mg/kg once daily (maximum 1,000 mg) for 10 days; this once-daily dosing may enhance adherence 1
- Intramuscular benzathine penicillin G: 1.2 million units as a single dose may be considered if oral adherence is a concern 1
Treatment for Penicillin-Allergic Patients
- For non-anaphylactic penicillin allergy: First-generation cephalosporins (e.g., cephalexin) for 10 days 1, 2
- For anaphylactic penicillin allergy: 1, 2
- Clindamycin: 7 mg/kg three times daily (maximum 300 mg per dose) for 10 days
- Clarithromycin: 7.5 mg/kg twice daily (maximum 250 mg per dose) for 10 days
- Azithromycin: 12 mg/kg once daily (maximum 500 mg) for 5 days (note: increasing resistance in some areas) 3
Diagnostic Considerations
- Diagnosis should be confirmed with rapid antigen detection test (RADT) and/or throat culture before initiating treatment 1
- A positive RADT is diagnostic and does not require backup culture 1
- A negative RADT in children and adolescents should be followed by a throat culture 1
Adjunctive Therapy
- Acetaminophen or NSAIDs can be used for moderate to severe symptoms or high fever 1
- Aspirin should be avoided in children due to risk of Reye syndrome 1
- Corticosteroids are not recommended as adjunctive therapy 1
Important Clinical Considerations
- Treatment should be initiated promptly to prevent complications such as rheumatic fever 4, 5
- The full 10-day course of antibiotics must be completed to ensure eradication of the organism, even if symptoms resolve earlier 4, 6
- Clinical response is usually achieved within 24-48 hours of initiating appropriate antibiotic therapy 1
- Bacteriologic failure rates with penicillin have increased over time (now approximately 30%), often due to poor adherence to the full 10-day regimen 7
Common Pitfalls to Avoid
- Treating without confirming diagnosis through testing, as clinical features alone cannot reliably distinguish between viral and bacterial pharyngitis 1
- Discontinuing antibiotics prematurely when symptoms improve, which can lead to treatment failure and potential complications 4, 6
- Using macrolides (azithromycin, clarithromycin) in areas with high resistance rates 3, 6
- Prescribing broad-spectrum antibiotics unnecessarily when narrow-spectrum options are effective 1
Follow-Up Recommendations
- Routine post-treatment throat cultures are not recommended unless symptoms persist or recur 1
- Patients with worsening symptoms after antibiotic initiation or symptoms lasting 5 days after starting treatment should be reevaluated 6
- For recurrent episodes, consider whether the patient is experiencing true recurrent infections or is a chronic carrier with viral infections 1, 2