What is the recommended treatment for strep (streptococcal) pharyngitis?

Treatment of Streptococcal Pharyngitis

Penicillin or amoxicillin is the first-line treatment for strep pharyngitis in non-allergic patients, given for 10 days to eradicate the organism and prevent rheumatic fever. 1

First-Line Treatment for Non-Allergic Patients

• Penicillin V is the drug of choice at 250 mg four times daily OR 500 mg twice daily for 10 days in adults 1
• Amoxicillin is equally effective and offers simpler dosing: 50 mg/kg once daily (maximum 1000 mg) OR 25 mg/kg twice daily (maximum 500 mg per dose) for 10 days 1
• Benzathine penicillin G intramuscularly provides single-dose treatment: 600,000 units for patients <27 kg; 1,200,000 units for patients ≥27 kg 1

These agents are preferred based on their narrow spectrum of activity, infrequency of adverse reactions, modest cost, and proven efficacy in preventing acute rheumatic fever 1. No penicillin resistance has been documented in Group A Streptococcus anywhere in the world 2.

Treatment for Penicillin-Allergic Patients

Non-Immediate (Non-Anaphylactic) Penicillin Allergy

First-generation cephalosporins are the preferred alternatives for patients without immediate hypersensitivity reactions 1, 2:

• Cephalexin: 20 mg/kg per dose twice daily (maximum 500 mg per dose) for 10 days 1
• Cefadroxil: 30 mg/kg once daily (maximum 1 gram) for 10 days 1

The cross-reactivity risk with first-generation cephalosporins is only 0.1% in patients with non-severe, delayed penicillin reactions 2.

Immediate/Anaphylactic Penicillin Allergy

Patients with immediate hypersensitivity (anaphylaxis, angioedema, urticaria within 1 hour) must avoid ALL beta-lactam antibiotics, including cephalosporins, due to up to 10% cross-reactivity risk 1, 2.

Clindamycin is the preferred alternative 1, 2:

• Dosing: 7 mg/kg per dose three times daily (maximum 300 mg per dose) for 10 days 1
• Advantages: Only ~1% resistance rate among Group A Streptococcus in the United States; highly effective even in chronic carriers 2

Macrolide alternatives (if clindamycin cannot be used) 1:

• Azithromycin: 12 mg/kg once daily (maximum 500 mg) for 5 days 1
• Clarithromycin: 7.5 mg/kg per dose twice daily (maximum 250 mg per dose) for 10 days 1

Critical Treatment Duration Requirements

A full 10-day course is essential for all antibiotics EXCEPT azithromycin to achieve maximal pharyngeal eradication and prevent acute rheumatic fever 1, 2. Azithromycin requires only 5 days due to its prolonged tissue half-life 1, 2. Shortening the course by even a few days results in appreciable increases in treatment failure rates 2.

Important Resistance Considerations

• Macrolide resistance among Group A Streptococcus is approximately 5-8% in the United States but varies geographically and temporally 1, 2
• Clindamycin resistance remains very low at approximately 1% in the United States 2
• Because of resistance concerns, azithromycin should be reserved for patients who cannot use penicillin, cephalosporins, or clindamycin 2, 3

Adjunctive Symptomatic Therapy

• Acetaminophen or NSAIDs (such as ibuprofen) should be considered for moderate to severe symptoms or high fever 1
• Aspirin must be avoided in children due to risk of Reye syndrome 1, 2
• Corticosteroids are NOT recommended as adjunctive therapy 1, 2

Common Pitfalls to Avoid

• Do not use cephalosporins in patients with immediate/anaphylactic penicillin reactions - the 10% cross-reactivity risk makes this dangerous 1, 2
• Do not shorten treatment courses below 10 days (except azithromycin's 5-day regimen) - this increases treatment failure and rheumatic fever risk 1, 2
• Do not use azithromycin as first-line therapy - it should only be used when penicillin and preferred alternatives cannot be used due to resistance concerns 2
• Do not prescribe broad-spectrum cephalosporins when narrow-spectrum first-generation agents are appropriate - this unnecessarily increases cost and antibiotic resistance 2
• Do not use trimethoprim-sulfamethoxazole for strep throat - resistance rates are high (50%) and it is not effective against Group A Streptococcus 2

Special Considerations

• Therapy can be safely postponed up to 9 days after symptom onset and still prevent acute rheumatic fever 2
• Routine post-treatment throat cultures or rapid antigen tests are NOT recommended for asymptomatic patients who have completed therapy 1, 2
• Chronic carriers generally do not require treatment as they are unlikely to spread infection or develop complications 1, 2
• Asymptomatic household contacts should NOT be tested or treated routinely 1