What is the recommended treatment for a patient with a sore throat suspected to be caused by Group A Streptococcus (GAS)?

Treatment of Group A Streptococcal Pharyngitis

Penicillin or amoxicillin for 10 days is the first-line treatment for confirmed GAS pharyngitis, based on proven efficacy, narrow spectrum, safety profile, and low cost. 1

Diagnostic Confirmation Required Before Treatment

• Testing with rapid antigen detection test (RADT) or throat culture must be performed before prescribing antibiotics, as clinical features alone cannot reliably distinguish GAS from viral pharyngitis 1, 2
• A positive RADT is diagnostic and does not require backup culture due to high specificity 1, 2
• In children and adolescents, negative RADT results should be confirmed with throat culture, though this is not routinely necessary in adults given the lower incidence of GAS and minimal risk of acute rheumatic fever 1
• Testing is not recommended when overt viral features are present (cough, rhinorrhea, hoarseness, oral ulcers) 1, 3

First-Line Antibiotic Treatment

For non-penicillin-allergic patients:

• Penicillin V 250 mg orally 2-3 times daily for 10 days (adults) or amoxicillin 50 mg/kg once daily (maximum 1,000 mg) for 10 days (children) are the recommended first-line options 1, 2
• Amoxicillin is often preferred in young children due to better palatability and once-daily dosing, which enhances adherence 1, 2
• The full 10-day course is essential to achieve maximal pharyngeal eradication of GAS and prevent acute rheumatic fever 1, 4
• Penicillin-resistant GAS has never been documented 1

Treatment for Penicillin-Allergic Patients

For non-anaphylactic penicillin allergy:

• First-generation cephalosporins such as cephalexin 20 mg/kg per dose twice daily (maximum 500 mg per dose) for 10 days are recommended due to low cross-reactivity risk 1, 2, 5

For anaphylactic/immediate-type penicillin allergy:

• Clindamycin 7 mg/kg per dose three times daily (maximum 300 mg per dose) for 10 days is the preferred alternative 1, 2, 5
• Clarithromycin 7.5 mg/kg per dose twice daily (maximum 250 mg per dose) for 10 days is an acceptable alternative 1, 2, 5
• Azithromycin 12 mg/kg once daily (maximum 500 mg) for 5 days is FDA-approved for shorter-course therapy 1, 6

Important Caveat on Macrolides

• Azithromycin achieves similar clinical success rates (94-95%) but significantly lower bacteriologic eradication rates (31-38%) compared to penicillin (68-81%) at Day 28 7
• Despite lower eradication rates, no increase in GAS-related sequelae has been documented with azithromycin 7
• Macrolide resistance rates vary geographically (5-8% in most US areas), which should be considered when selecting treatment 2, 5

Adjunctive Symptomatic Treatment

• NSAIDs (ibuprofen) or acetaminophen should be used for moderate to severe symptoms or high fever control 1, 2, 3, 8
• NSAIDs are more effective than acetaminophen for fever and pain relief 8
• Aspirin must be avoided in children due to the risk of Reye syndrome 1, 2, 3
• Corticosteroids are not recommended for routine use, as they provide only minimal symptom reduction (approximately 5 hours) with potential adverse effects 1, 3
• Medicated throat lozenges containing topical anesthetics (ambroxol, lidocaine, benzocaine) used every 2 hours may provide temporary relief 2, 3, 8

Expected Clinical Response

• Clinical improvement typically occurs within 24-48 hours of initiating appropriate antibiotic therapy 1
• GAS pharyngitis is a self-limited disease, but antibiotic treatment shortens symptom duration by 1-2 days, reduces complications, and decreases contagiousness 3

Special Considerations for Recurrent Cases

• Patients with recurrent episodes may be chronic pharyngeal GAS carriers experiencing repeated viral infections rather than true recurrent bacterial infections 1, 2, 5
• Each suspected episode must be confirmed with RADT or throat culture before treating 5
• Clindamycin demonstrates substantially higher eradication rates than penicillin in chronic carriers and may protect against recurrence for at least 3 months 2, 9
• Tonsillectomy may be considered for children meeting specific frequency criteria (≥7 episodes in 1 year, ≥5 episodes/year for 2 years, or ≥3 episodes/year for 3 years) 5

Critical Pitfalls to Avoid

• Never prescribe antibiotics without diagnostic confirmation, as most sore throats are viral and do not benefit from antibiotics 1, 2, 3
• Never use cephalosporins in patients with anaphylactic/immediate-type penicillin reactions due to cross-reactivity risk 2
• Never shorten antibiotic courses below 10 days for penicillin or amoxicillin (except azithromycin at 5 days), as incomplete courses increase treatment failure risk and complications 1, 2, 3
• Never use trimethoprim-sulfamethoxazole (Bactrim) due to high GAS resistance rates 2
• Never routinely test or treat asymptomatic household contacts, as this is not warranted given the self-limited nature of GAS pharyngitis and limited efficacy of prophylaxis 1
• Never perform follow-up throat cultures or RADT routinely after treatment completion, though this may be considered in special circumstances 1