Treatment for Streptococcal Pharyngitis
Penicillin or amoxicillin for 10 days is the first-line treatment for streptococcal pharyngitis due to proven efficacy, safety, narrow spectrum, and low cost. 1, 2, 3
First-Line Antibiotic Regimens
For Patients Without Penicillin Allergy
Penicillin V remains the preferred agent due to its narrow spectrum of activity, proven efficacy over decades, excellent safety profile, and low cost 1, 2, 4. There has never been a documented case of penicillin-resistant Group A Streptococcus anywhere in the world 3.
Dosing for Penicillin V (10 days): 1, 2
- Children: 250 mg two or three times daily
- Adolescents and adults: 250 mg four times daily OR 500 mg twice daily
Amoxicillin is equally effective and often preferred in children due to better palatability of the suspension 1, 2, 3. Once-daily dosing improves adherence 3, 5.
Dosing for Amoxicillin (10 days): 1, 2, 3
- 50 mg/kg once daily (maximum 1,000 mg)
- Alternative: 25 mg/kg twice daily (maximum 500 mg per dose)
Intramuscular benzathine penicillin G should be used when compliance with oral therapy is questionable 1, 2:
- Patients <60 lb (27 kg): 600,000 units as single dose
- Patients ≥60 lb: 1,200,000 units as single dose
Treatment for Penicillin-Allergic Patients
Non-Immediate (Non-Anaphylactic) Allergy
First-generation cephalosporins for 10 days are recommended 1, 2, 3:
- Cephalexin: 20 mg/kg per dose twice daily (maximum 500 mg per dose)
- Cefadroxil: 30 mg/kg once daily (maximum 1 g)
Critical caveat: Avoid cephalosporins in patients with immediate hypersensitivity reactions to penicillin 1.
Immediate Hypersensitivity to Penicillin
Clindamycin is the preferred alternative for true anaphylactic penicillin allergy 1, 2, 3:
- 7 mg/kg per dose three times daily (maximum 300 mg per dose) for 10 days
Macrolides are second-line alternatives due to increasing resistance 1, 2, 6:
- Azithromycin: 12 mg/kg once daily (maximum 500 mg) for 5 days only
- Clarithromycin: 7.5 mg/kg per dose twice daily (maximum 250 mg per dose) for 10 days
Important resistance consideration: There is significant resistance to azithromycin and clarithromycin in some parts of the United States, and susceptibility testing should be performed when using these agents 7, 6.
Critical Treatment Duration
The full 10-day course is essential for penicillin and most oral antibiotics to achieve maximal pharyngeal eradication of streptococci and prevent rheumatic fever 1, 2, 4, 8. Shorter courses have not been adequately validated for preventing rheumatic fever 2.
Exception: Azithromycin requires only 5 days due to its prolonged tissue half-life 1, 2.
Management of Treatment Failures and Chronic Carriers
For patients with recurrent positive cultures despite adequate treatment 1, 4:
First approach: Retreatment with the same regimen if compliance was adequate, or intramuscular benzathine penicillin G if compliance is questionable 1, 4.
For chronic carriers or multiple treatment failures: 1, 3
- Clindamycin: 20-30 mg/kg/day in three divided doses (maximum 300 mg per dose) for 10 days
- Amoxicillin/clavulanate: 40 mg amoxicillin/kg/day in three divided doses (maximum 2,000 mg amoxicillin per day) for 10 days
Important distinction: Patients with recurrent pharyngitis and positive cultures may be chronic carriers experiencing repeated viral infections rather than true treatment failures 1. Antibiotics are not generally recommended for asymptomatic carriers except in specific high-risk situations 1.
Adjunctive Symptomatic Treatment
Acetaminophen or NSAIDs may be used for moderate to severe symptoms or high fever 1, 2, 4.
Critical contraindications: 1, 2, 4
- Avoid aspirin in children due to risk of Reye syndrome
- Corticosteroids are not recommended
Common Pitfalls to Avoid
Do not prescribe antibiotics for viral pharyngitis characterized by cough, rhinorrhea, hoarseness, or oral ulcers 1, 4. Only 10% of adults with sore throat have streptococcal pharyngitis, yet 60% or more receive antibiotics 6.
Do not use broad-spectrum antibiotics like amoxicillin/clavulanate as first-line therapy as this increases costs, promotes antimicrobial resistance, and increases gastrointestinal side effects without providing additional clinical benefit 3.
Do not perform routine post-treatment throat cultures for asymptomatic patients who completed adequate therapy 1, 4.
Do not test or treat asymptomatic household contacts unless specific high-risk situations exist 1, 4.