Treatment of Pharyngitis
First-Line Antibiotic Therapy
Penicillin or amoxicillin for 10 days remains the definitive first-line treatment for Group A streptococcal (GAS) pharyngitis, based on proven efficacy, narrow spectrum, safety profile, and the absence of documented resistance. 1
Specific Dosing Regimens
For adults:
For children:
- Penicillin V 250 mg twice daily or three times daily for 10 days 1
- Amoxicillin 25 mg/kg/day divided twice daily (or 50 mg/kg once daily, maximum 1000 mg) for 10 days for children <40 kg 1
- Amoxicillin 500 mg twice daily for 10 days for children ≥40 kg 1
Intramuscular benzathine penicillin G is recommended when adherence is questionable. 1
Diagnostic Approach Before Treatment
Test patients with 2 or more Centor criteria using rapid antigen detection test (RADT) or throat culture before prescribing antibiotics. 2
Centor criteria include:
Do not test or treat patients with viral features such as cough, rhinorrhea, hoarseness, or oral ulcers, as these strongly suggest non-streptococcal etiology. 2
Children under 3 years generally do not require testing unless they have specific risk factors like an older sibling with GAS infection. 1
Treatment for Penicillin-Allergic Patients
Non-Immediate/Non-Anaphylactic Penicillin Allergy
First-generation cephalosporins are the preferred alternatives with strong, high-quality evidence. 1
Specific regimens:
- Cephalexin 500 mg orally every 12 hours for 10 days (adults) 4
- Cephalexin 20 mg/kg per dose twice daily (maximum 500 mg/dose) for 10 days (children) 4
- Cefadroxil 30 mg/kg once daily (maximum 1 gram) for 10 days (children) 4
Immediate/Anaphylactic Penicillin Allergy
Clindamycin is the preferred choice with approximately 1% resistance in the United States. 1
Specific regimen:
- Clindamycin 7 mg/kg per dose three times daily (maximum 300 mg/dose) for 10 days 4
Macrolides are acceptable alternatives but have higher resistance rates (5-8% in the US): 1
- Azithromycin 12 mg/kg once daily (maximum 500 mg) for 5 days 4
- Clarithromycin 7.5 mg/kg per dose twice daily (maximum 250 mg/dose) for 10 days 4
Critical Treatment Duration Requirements
A full 10-day course is mandatory for all antibiotics except azithromycin to achieve maximal pharyngeal eradication and prevent acute rheumatic fever. 1
Azithromycin requires only 5 days due to its prolonged tissue half-life. 1, 5
Shortening the course by even a few days results in appreciable increases in treatment failure rates and rheumatic fever risk. 4
Adjunctive Symptomatic Therapy
NSAIDs or acetaminophen should be used for moderate to severe symptoms or high fever. 2
Aspirin must be avoided in children due to Reye syndrome risk. 4
Corticosteroids are not recommended as adjunctive therapy. 4
Special Clinical Situations
Recurrent Pharyngitis
Distinguish between true recurrent infections versus chronic carrier with viral infections. 1
For documented recurrent GAS infections with treatment failures, clindamycin or amoxicillin-clavulanate may be used. 1
Chronic carriers generally do not require antimicrobial therapy, as they are unlikely to spread GAS pharyngitis and are at little risk for complications. 4
Pregnancy
Penicillin and amoxicillin remain first-line with proven safety. 1
For penicillin-allergic pregnant patients:
Post-Treatment Management
No routine follow-up cultures or RADTs are needed for asymptomatic patients who completed therapy. 2
Follow-up testing should only be considered in special circumstances, such as patients with a history of rheumatic fever. 4
Patients become non-contagious after 24 hours of appropriate antibiotic therapy. 2
Common Pitfalls to Avoid
Do not prescribe shorter courses than recommended (except azithromycin's 5-day regimen) as this increases treatment failure and rheumatic fever risk. 1
Do not use cephalosporins in patients with immediate/anaphylactic penicillin reactions due to 10% cross-reactivity. 1, 4
Check local macrolide resistance patterns before prescribing azithromycin or clarithromycin, as resistance varies geographically. 1
Do not use tetracyclines, sulfonamides, trimethoprim-sulfamethoxazole, or older fluoroquinolones as they are ineffective against GAS. 2
Do not prescribe broad-spectrum cephalosporins when narrow-spectrum first-generation agents are appropriate, as they are more expensive and more likely to select for antibiotic-resistant flora. 4