What is the 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, with no documented penicillin resistance ever reported worldwide. 1, 2

First-Line Antibiotic Regimens

Oral Therapy (Preferred for Most Patients)

Penicillin V:

• Children: 250 mg twice or three times daily for 10 days 1, 2
• Adolescents and adults: 250 mg four times daily OR 500 mg twice daily for 10 days 1, 2

Amoxicillin (equivalent efficacy with better palatability):

• 50 mg/kg once daily (maximum 1,000 mg) OR 25 mg/kg twice daily (maximum 500 mg per dose) for 10 days 2, 3

Intramuscular Therapy (When Compliance is Uncertain)

Benzathine penicillin G (single dose):

• Patients <60 lb (27 kg): 600,000 units 2
• Patients ≥60 lb: 1,200,000 units 1, 2

This option is particularly valuable in settings where follow-up is lacking, compliance cannot be assured, or in areas where rheumatic fever remains prevalent 1, 4. The single injection guarantees complete treatment and has been the gold standard since the 1950s for preventing rheumatic fever 1.

Treatment for Penicillin-Allergic Patients

Non-Immediate (Non-Anaphylactic) Penicillin Allergy

First-generation cephalosporins are preferred:

• Cephalexin: 20 mg/kg per dose twice daily (maximum 500 mg per dose) for 10 days 5, 2
• Cefadroxil: 30 mg/kg once daily (maximum 1 gram) for 10 days 5

The cross-reactivity risk is only 0.1% in patients with non-severe, delayed penicillin reactions 5. These agents provide strong, high-quality evidence for efficacy 5.

Immediate/Anaphylactic Penicillin Allergy

All beta-lactams must be avoided due to up to 10% cross-reactivity risk. 1, 5

Clindamycin (preferred alternative):

• 7 mg/kg per dose three times daily (maximum 300 mg per dose) for 10 days 5, 2
• Resistance rate is approximately 1% in the United States 5
• Highly effective at eradicating streptococci, even in chronic carriers 1, 5

Azithromycin (acceptable alternative):

• 12 mg/kg once daily (maximum 500 mg) for 5 days 5, 2, 6
• Only antibiotic requiring just 5 days due to prolonged tissue half-life 5, 6
• Macrolide resistance is 5-8% in the United States, varying geographically 1, 5

Clarithromycin:

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

Erythromycin (less preferred due to gastrointestinal side effects):

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

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, 5, 2, 3 Shortening the course by even a few days results in appreciable increases in treatment failure rates 5. Therapy can be safely postponed up to 9 days after symptom onset and still prevent rheumatic fever 5.

Adjunctive Symptomatic Therapy

Analgesics/Antipyretics:

• Acetaminophen or NSAIDs (ibuprofen) should be considered for moderate to severe symptoms or high fever 1, 5, 2
• Multiple randomized, double-blind, placebo-controlled studies demonstrate significant pain and fever reduction 1
• Aspirin must be avoided in children due to Reye syndrome risk 1, 5, 2

Corticosteroids are NOT recommended:

• Although they decrease symptom duration by approximately 5 hours, the minimal benefit does not justify potential adverse effects 1
• Given the efficacy of antimicrobials and analgesics, corticosteroids add no meaningful clinical value 1

Management of Recurrent Episodes

For patients with recurrent pharyngitis and positive testing:

• Consider retreatment with the same initial agent if compliance was good 1
• Use intramuscular benzathine penicillin G if oral compliance is questionable 1, 2
• Clindamycin or amoxicillin-clavulanate may be beneficial for chronic carriers due to high pharyngeal eradication rates 1

Important distinction: Patients may be chronic pharyngeal GAS carriers experiencing repeated viral infections rather than true recurrent streptococcal infections 1. Chronic carriers do not ordinarily require antimicrobial therapy as they are unlikely to spread infection or develop complications 1, 5.

Common Pitfalls to Avoid

Do not use these agents for streptococcal pharyngitis:

• Sulfonamides and tetracyclines have high resistance rates and frequent treatment failures 1, 3
• Trimethoprim-sulfamethoxazole has 50% resistance and is not effective 5, 3

Do not prescribe cephalosporins to patients with immediate/anaphylactic penicillin reactions due to the 10% cross-reactivity risk 1, 5.

Do not routinely perform post-treatment throat cultures on asymptomatic patients who have completed therapy 1, 2. Testing should only be considered in special circumstances, such as patients with a history of rheumatic fever 5.

Do not treat likely viral pharyngitis (patients with cough, rhinorrhea, hoarseness, or oral ulcers) with antibiotics 2.

Do not consider tonsillectomy solely to reduce frequency of GAS pharyngitis 1.

Treatment Goals and Outcomes

The primary objectives are: (1) prevention of acute rheumatic fever, (2) prevention of suppurative complications (peritonsillar abscess, cervical lymphadenitis, mastoiditis), (3) rapid symptom resolution, (4) decreased transmission to contacts, and (5) minimization of adverse effects 1. Early treatment reduces symptom duration to less than 24 hours in most cases and permits earlier return to normal activities 4.