What is the recommended treatment for streptococcal pharyngitis?

Treatment of Streptococcal Pharyngitis

Penicillin V (250 mg four times daily OR 500 mg twice daily) or amoxicillin (50 mg/kg once daily, maximum 1000 mg) for a full 10 days is the recommended first-line treatment for streptococcal pharyngitis in non-allergic patients. 1, 2

First-Line Treatment for Non-Allergic Patients

• Penicillin V or amoxicillin remains the drug of choice due to proven efficacy, narrow spectrum, safety profile, and low cost, with no documented penicillin resistance in Group A Streptococcus anywhere in the world. 1, 2

• Penicillin V dosing options for adults and adolescents: 250 mg four times daily OR 500 mg twice daily for 10 days 1, 2, 3, 4

• Amoxicillin dosing: 50 mg/kg once daily (maximum 1000 mg) OR 25 mg/kg twice daily (maximum 500 mg/dose) for 10 days 1, 2

• Amoxicillin is often preferred in children due to better palatability and once-daily dosing convenience 2

• Intramuscular benzathine penicillin G as a single dose (600,000 units if <27 kg; 1,200,000 units if ≥27 kg) ensures compliance when adherence to oral therapy is uncertain, particularly in populations where follow-up may be lacking 2

Critical Treatment Duration

• A full 10-day course is essential for all antibiotics except azithromycin to achieve maximal pharyngeal eradication and prevent acute rheumatic fever. 1, 5, 2

• Shortening the course by even a few days results in appreciable increases in treatment failure rates and risk of rheumatic fever 5

• Therapy can be safely postponed up to 9 days after symptom onset and still prevent acute rheumatic fever 5

Treatment for Penicillin-Allergic Patients

Non-Immediate (Non-Anaphylactic) Penicillin Allergy

• First-generation cephalosporins are the preferred first-line alternatives for patients with non-immediate penicillin allergies, with cross-reactivity risk of less than 3-10%. 1, 5, 2

• Cephalexin 20 mg/kg per dose twice daily (maximum 500 mg/dose) for 10 days 1, 5, 2

• Cefadroxil 30 mg/kg once daily (maximum 1 gram) for 10 days 5, 2

• Cross-reactivity risk is only 0.1% in patients with non-severe, delayed penicillin reactions 5

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, 5, 2

• Clindamycin is the preferred alternative for immediate/anaphylactic penicillin allergy: 7 mg/kg per dose three times daily (maximum 300 mg/dose) for 10 days. 1, 5, 2

• Clindamycin has approximately 1% resistance rate among Group A Streptococcus in the United States and demonstrates high efficacy even in chronic carriers 5, 2

• Macrolides (azithromycin, clarithromycin) are acceptable alternatives but carry concerns about resistance 1, 5

Macrolide Options (When Clindamycin Cannot Be Used)

• Azithromycin: 12 mg/kg once daily (maximum 500 mg) for 5 days 1, 5, 6

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

• Erythromycin: 20-40 mg/kg/day divided 2-3 times daily (maximum 1 gram per day) for 10 days 5

• Macrolide resistance among Group A Streptococcus is approximately 5-8% in the United States and varies geographically, making clindamycin more reliable in areas with high resistance rates. 1, 5

• Azithromycin is the only antibiotic requiring just 5 days due to its prolonged tissue half-life, but data establishing efficacy in subsequent prevention of rheumatic fever are not available. 5, 6

Critical Pitfalls to Avoid

• Do not use cephalosporins in patients with immediate/anaphylactic penicillin reactions due to 10% cross-reactivity risk. 1, 5, 2

• Do not use tetracyclines, sulfonamides, or trimethoprim-sulfamethoxazole due to high prevalence of resistant strains or lack of efficacy. 1, 5

• Do not prescribe shorter courses than recommended (except azithromycin's 5-day regimen) as this leads to treatment failure and complications. 1, 5

• Do not use azithromycin as first-line therapy—it should only be used when penicillin and preferred alternatives cannot be used. 5

• Do not assume all penicillin-allergic patients cannot receive cephalosporins—only those with immediate/anaphylactic reactions should avoid them. 5

Adjunctive Symptomatic Treatment

• Acetaminophen or NSAIDs (such as ibuprofen) for moderate to severe symptoms or high fever 1, 5

• Aspirin must be avoided in children due to risk of Reye syndrome. 5

• Corticosteroids are not recommended as adjunctive therapy. 5

Follow-Up and Special Circumstances

• Routine post-treatment throat cultures or rapid antigen tests are not recommended for asymptomatic patients who have completed therapy. 1, 5

• Reevaluation is suggested for patients with worsening symptoms after 48-72 hours or symptoms lasting more than 5 days after treatment initiation 1

• Do not perform diagnostic testing or empiric treatment of asymptomatic household contacts, as penicillin prophylaxis has not been shown to reduce subsequent infection rates. 1

• Chronic carriers generally do not require antimicrobial therapy, as they are unlikely to spread infection and are at little risk for complications 5

• For recurrent streptococcal pharyngitis or chronic carriers with multiple treatment failures, clindamycin may be particularly effective due to its ability to eradicate the organism 5, 2