What is the appropriate management and antibiotic regimen for acute Group A Streptococcus pharyngitis in an otherwise healthy adult or child presenting with sore throat, fever, tonsillar exudates, tender anterior cervical lymphadenopathy, and no cough?

Management of Group A Streptococcal Pharyngitis

Amoxicillin 500 mg orally twice daily for 10 days (or penicillin V 500 mg twice daily for 10 days) is the definitive first-line treatment for laboratory-confirmed Group A streptococcal pharyngitis in adults and children, regardless of whether tonsillar exudates are present. 1

Diagnostic Approach

Testing is required before prescribing antibiotics:

• Perform a rapid antigen detection test (RADT) or throat culture in patients with clinical features suggesting bacterial infection: fever, tonsillar exudates, tender anterior cervical lymphadenopathy, and absence of cough. 2, 1
• A positive RADT alone is sufficient for diagnosis and does not require backup culture. 1
• Do not test or treat patients with clear viral features (cough, rhinorrhea, hoarseness, conjunctivitis, oral ulcers), as these strongly suggest viral etiology and do not warrant antibiotics. 2, 3
• Testing is generally not recommended in children under 3 years unless specific risk factors are present, as Group A streptococcus is uncommon in this age group. 1, 4

First-Line Antibiotic Therapy

Penicillin and amoxicillin remain the gold standard:

• Adults: Amoxicillin 500 mg orally twice daily for 10 days OR penicillin V 500 mg orally 2-3 times daily for 10 days. 1
• Children: Amoxicillin 50 mg/kg once daily (maximum 1000 mg) OR 25 mg/kg twice daily (maximum 500 mg per dose) for 10 days. 1
• Alternative for children: Penicillin V 250 mg orally 2-3 times daily for 10 days. 1

Rationale for penicillin/amoxicillin preference:

• Zero documented resistance worldwide among Group A streptococcus, ensuring 100% susceptibility. 1
• Proven efficacy in preventing acute rheumatic fever, the primary therapeutic goal. 1
• Narrow antimicrobial spectrum reduces selection pressure for resistant flora. 1
• Excellent safety profile and lowest cost. 1
• Amoxicillin is often preferred over penicillin V due to better palatability and more convenient twice-daily dosing. 1

Intramuscular option when adherence is uncertain:

• Benzathine penicillin G: 600,000 units (if <27 kg) or 1,200,000 units (if ≥27 kg) as a single IM dose. 1

Treatment Duration: Non-Negotiable 10-Day Course

A complete 10-day course is mandatory for penicillin and amoxicillin:

• Required to achieve maximal pharyngeal eradication and prevent acute rheumatic fever, even if symptoms improve within 3-4 days. 1
• Shortening the course by even a few days markedly increases treatment failure rates and rheumatic fever risk. 1
• The only exception is azithromycin, which requires only 5 days due to its prolonged tissue half-life. 1
• Therapy can be initiated up to 9 days after symptom onset and still effectively prevent acute rheumatic fever. 1

Management of Penicillin-Allergic Patients

For non-immediate (delayed) penicillin allergy:

• First-generation cephalosporins are preferred: Cephalexin 500 mg orally twice daily for 10 days (adults) or 20 mg/kg twice daily for 10 days (children, maximum 500 mg per dose). 1
• Cross-reactivity risk is only 0.1% with delayed reactions. 1

For immediate/anaphylactic penicillin allergy:

• Clindamycin is the preferred agent: 300 mg orally three times daily for 10 days (adults) or 7 mg/kg three times daily for 10 days (children, maximum 300 mg per dose). 1
• Clindamycin has only ~1% resistance among U.S. Group A streptococcus isolates and shows superior eradication in chronic carriers. 1
• Azithromycin is an acceptable alternative: 500 mg orally once daily for 5 days (adults) or 12 mg/kg once daily for 5 days (children, maximum 500 mg). 1
• Macrolide resistance in the United States ranges from 5-8%, which is a significant concern. 1

Critical pitfall to avoid:

• Do not use cephalosporins in patients with anaphylaxis, angioedema, or immediate urticaria to penicillin due to 10% cross-reactivity risk. 1

Clinical Benefits of Treatment

Antibiotic therapy provides modest but meaningful benefits:

• Shortens duration of sore throat by approximately 1-2 days (number needed to treat = 6 at day 3,21 at day 7). 2, 1
• Prevents suppurative complications such as peritonsillar abscess. 4
• The primary justification for treatment is prevention of acute rheumatic fever, which can cause permanent cardiac damage. 1
• Reduces contagiousness and transmission to close contacts. 4

Adjunctive Symptomatic Management

Pain and fever control:

• Offer acetaminophen or NSAIDs (such as ibuprofen) for moderate to severe symptoms or fever. 1, 3
• Aspirin must be avoided in children due to risk of Reye syndrome. 1, 3
• Topical anesthetics (lozenges containing ambroxol, lidocaine, or benzocaine) may provide temporary relief. 3
• Warm salt water gargles can be used in patients old enough to gargle. 3

Corticosteroids are not recommended:

• Provide only minimal symptom reduction (~5 hours) with potential adverse effects. 3
• Not recommended for routine use in Group A streptococcal pharyngitis. 1, 3

Management of Household Contacts and Follow-Up

Asymptomatic contacts:

• Do not routinely test or treat asymptomatic household members; up to one-third are asymptomatic carriers, and prophylactic therapy does not reduce subsequent infection rates. 1

Post-treatment testing:

• Routine follow-up testing after completion of therapy in asymptomatic patients is unnecessary; positive results usually reflect carrier status rather than treatment failure. 1

Critical Pitfalls to Avoid

• Never prescribe antibiotics for viral pharyngitis (patients with cough, rhinorrhea, hoarseness, oral ulcers); this provides no benefit and contributes to antibiotic resistance. 2, 3
• Never shorten the 10-day course of penicillin or amoxicillin, even if symptoms resolve early; this increases treatment failure and rheumatic fever risk. 1
• Never withhold antibiotics solely because exudates are absent; laboratory confirmation of Group A streptococcus is the sole criterion for therapy. 1
• Never use azithromycin as first-line therapy when penicillin/amoxicillin can be used; reserve it only for immediate penicillin allergy when clindamycin cannot be tolerated. 1
• Never rely on clinical features alone to diagnose Group A streptococcal pharyngitis; no clinical signs or scores have adequate predictive value without laboratory confirmation. 2, 4