What is the recommended treatment for a 14-year-old patient with strep throat?

Treatment of Strep Throat in a 14-Year-Old

For a 14-year-old with confirmed streptococcal pharyngitis, prescribe oral amoxicillin 50 mg/kg once daily (maximum 1,000 mg) or 25 mg/kg twice daily (maximum 500 mg per dose) for a full 10 days. 1

Diagnostic Confirmation Required First

Before prescribing antibiotics, you must confirm Group A Streptococcus (GAS) infection with testing 2:

• Perform a rapid antigen detection test (RADT) first 1
• If RADT is negative, follow up with a throat culture in adolescents, as the incidence of strep throat and risk of rheumatic fever remain significant in this age group 2
• Do not prescribe antibiotics based on clinical features alone, even with classic findings like tonsillar exudates, fever, and anterior cervical adenitis 2

First-Line Antibiotic Treatment

Amoxicillin is the preferred first-line agent for this age group 1, 3:

• Dosing: 50 mg/kg once daily (maximum 1,000 mg) OR 25 mg/kg twice daily (maximum 500 mg per dose) 1
• Duration: Full 10 days mandatory 1, 2
• Why amoxicillin over penicillin V: Better palatability, proven equivalent efficacy, and convenient once-daily dosing option that improves adherence 1, 3

Penicillin V remains an acceptable alternative 2:

• Dosing for adolescents: 500 mg twice daily OR 250 mg four times daily for 10 days 2
• Key advantage: No documented penicillin resistance in GAS anywhere in the world 1

Critical Treatment Duration

The full 10-day course is non-negotiable 1, 2:

• Shortening the course by even a few days dramatically increases treatment failure rates and risk of acute rheumatic fever 1
• Even though symptoms typically resolve within 3-4 days, bacterial eradication requires the full course 1, 3
• The primary goal is preventing acute rheumatic fever and suppurative complications, not just symptom relief 1, 3

Treatment for Penicillin-Allergic Patients

Determine the type of allergic reaction first 1, 3:

Non-Anaphylactic Penicillin Allergy

• First-generation cephalosporins are safe and preferred 1, 3
• Cephalexin: 20 mg/kg per dose twice daily (maximum 500 mg per dose) for 10 days 1, 3
• Cross-reactivity risk is only 0.1% with non-immediate reactions 3

Immediate/Anaphylactic Penicillin Allergy

• Avoid all beta-lactams including cephalosporins due to up to 10% cross-reactivity risk 1, 3
• Clindamycin is the preferred choice: 7 mg/kg per dose three times daily (maximum 300 mg per dose) for 10 days 1, 3
• Clindamycin has only ~1% resistance among GAS in the United States 1, 3
• Azithromycin is an alternative: 12 mg/kg once daily (maximum 500 mg) for 5 days 1, 3
• However, macrolide resistance is 5-8% in the United States, making clindamycin more reliable 1, 3

Adjunctive Symptomatic Treatment

For moderate to severe symptoms or high fever 1, 2:

• Acetaminophen or NSAIDs (ibuprofen) for pain and fever control 1, 2
• Never use aspirin in adolescents due to Reye syndrome risk 1, 2
• Corticosteroids are not recommended 2

Common Pitfalls to Avoid

Do not use these antibiotics for strep throat 1:

• Trimethoprim-sulfamethoxazole (Bactrim): 50% resistance rate, not effective against GAS 1
• Broad-spectrum cephalosporins (cefdinir, cefixime, cefpodoxime): More expensive, promote resistance when narrow-spectrum agents are appropriate 1, 3

Do not shorten the treatment course 1, 2:

• Even if the patient feels better after 3-4 days, the full 10-day course (except azithromycin's 5-day regimen) is essential 1, 2
• Incomplete treatment increases treatment failure and rheumatic fever risk 1

Do not perform routine post-treatment testing 1, 3:

• Throat cultures after completing therapy are not recommended for asymptomatic patients 1, 3
• Consider follow-up testing only in special circumstances, such as patients with a history of rheumatic fever 3

Why This Treatment Matters

Antibiotics provide modest symptom reduction (shortening illness by about 1-2 days) but are critical for preventing serious complications 2, 4:

• Acute rheumatic fever: Antibiotics reduce risk to less than one-third 4
• Suppurative complications: Antibiotics reduce acute otitis media to one-quarter and peritonsillar abscess to one-sixth of untreated rates 4
• Symptom relief: Number needed to treat is 5 at day 3 and 14 at one week 4