What is the recommended treatment for streptococcal pharyngitis?

Treatment of Streptococcal Pharyngitis

Penicillin or amoxicillin remains the first-line treatment for streptococcal pharyngitis due to proven efficacy, safety, narrow spectrum, and low cost. 1

First-Line Treatment for Patients Without Penicillin Allergy

Oral penicillin V or amoxicillin for 10 days is the gold standard treatment. 1, 2

Specific Dosing Regimens:

Penicillin V (oral): 1, 2

• Children: 250 mg two or three times daily for 10 days
• Adolescents and adults: 250 mg four times daily OR 500 mg twice daily for 10 days

Amoxicillin (oral): 1, 2

• 50 mg/kg once daily (maximum 1,000 mg) for 10 days
• Alternative: 25 mg/kg twice daily (maximum 500 mg per dose) for 10 days
• Amoxicillin is often preferred in young children due to better taste acceptance 1

Intramuscular benzathine penicillin G (single dose): 1, 2

• Patients <60 lb (27 kg): 600,000 units
• Patients ≥60 lb: 1,200,000 units
• This option is particularly important for patients unlikely to complete oral therapy or in settings where compliance cannot be assured 1, 3

Evidence Supporting Once-Daily Amoxicillin:

Recent high-quality evidence demonstrates that once-daily amoxicillin (750 mg for children <40 kg, 1000 mg for ≥40 kg) is non-inferior to twice-daily dosing, with bacteriologic failure rates of 20.1% at 14-21 days and only 2.8% at 28-35 days. 4 This regimen offers improved convenience and comparable efficacy to traditional multi-dose regimens. 5

Treatment for Patients With Penicillin Allergy

The choice of alternative antibiotic depends on whether the patient has immediate-type (anaphylactic) hypersensitivity to penicillin. 1, 6, 7

For Non-Anaphylactic Penicillin Allergy:

First-generation cephalosporins are the preferred alternative: 1, 6, 7

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

For Immediate/Anaphylactic Penicillin Allergy:

Avoid cephalosporins due to up to 10% cross-reactivity risk. 7 Use one of the following:

Clindamycin: 1, 6, 7

• 7 mg/kg per dose three times daily (maximum 300 mg per dose) for 10 days
• Particularly effective for chronic carriers with resistance rates around 1% in the United States 7

Azithromycin: 1, 6, 8

• 12 mg/kg once daily (maximum 500 mg) for 5 days
• Only macrolide requiring just 5 days due to prolonged tissue half-life 7, 8
• Clinical success rates of 98% at Day 14 and 94% at Day 30 in controlled trials 8

Clarithromycin: 1, 6

• 7.5 mg/kg per dose twice daily (maximum 250 mg per dose) for 10 days

Critical Diagnostic Considerations

Testing should be performed for patients with clinical features suggesting streptococcal infection: 2

• Sudden onset of sore throat
• Fever
• Tonsillopharyngeal inflammation or exudates
• Tender anterior cervical lymphadenopathy
• Age 5-15 years

Avoid testing and treatment when viral features predominate: 1, 2

• Cough, rhinorrhea, hoarseness, conjunctivitis, or oral ulcers strongly suggest viral etiology 1

A positive rapid antigen detection test (RADT) is diagnostic and requires no backup culture in adults. 1 However, negative RADT results in children and adolescents should be confirmed with throat culture. 1, 2

Important Resistance and Efficacy Considerations

Macrolide resistance among Group A Streptococcus varies geographically, with approximately 5-8% resistance in the United States. 1, 7 In areas with high macrolide resistance, cephalosporins or clindamycin are preferred over macrolides for penicillin-allergic patients. 7

Cephalosporins demonstrate lower clinical relapse rates compared to penicillin (OR 0.55; 95% CI 0.31-0.99), though symptom resolution is comparable. 1

Short-course macrolides show greater risk of late bacteriological recurrence (OR 1.31; 95% CI 1.16-1.48) compared to 10-day penicillin courses. 1

Adjunctive Therapy

NSAIDs or acetaminophen can be used for moderate to severe symptoms or high fever. 1, 2 NSAIDs are more effective than acetaminophen for pain and fever control. 9

Avoid aspirin in children due to risk of Reye syndrome. 1, 2

Corticosteroids are not recommended for routine use as they provide only minimal symptom reduction. 1, 9

Management of Recurrent Pharyngitis

For patients with recurrent positive cultures shortly after treatment completion: 1

• Retreat with the same antimicrobial agent initially used
• If compliance with oral therapy is questionable, use intramuscular benzathine penicillin G
• Consider clindamycin or amoxicillin-clavulanate for suspected chronic carriers 6

Distinguish true recurrent infections from chronic carriers experiencing viral infections. 6 Chronic carriers generally do not require antimicrobial therapy as they are unlikely to spread infection or develop complications. 7

Common Pitfalls to Avoid

Do not perform routine post-treatment throat cultures in asymptomatic patients who have completed therapy. 1, 2 Follow-up testing is only indicated in special circumstances such as patients with history of rheumatic fever. 7

Do not routinely test or treat asymptomatic household contacts. 1

Do not prescribe antibiotics for likely viral pharyngitis based on clinical features (cough, rhinorrhea, hoarseness, oral ulcers). 2

Do not use trimethoprim-sulfamethoxazole for streptococcal pharyngitis due to high resistance rates (50%). 7

Ensure full 10-day courses for all antibiotics except azithromycin to achieve maximal pharyngeal eradication and prevent rheumatic fever. 1, 2 Shorter courses (except azithromycin's 5-day regimen) lead to treatment failure and complications. 7