Treatment of Group A Streptococcal (GAS) Pharyngitis
Penicillin or amoxicillin for 10 days is the treatment of choice for confirmed GAS pharyngitis due to proven efficacy, narrow spectrum, lack of resistance, and low cost. 1
First-Line Treatment for Non-Allergic Patients
Oral penicillin V remains the gold standard, with dosing of 250 mg twice or three times daily for children, and 250 mg three to four times daily or 500 mg twice daily for adolescents and adults, all for 10 days. 2 Penicillin-resistant GAS has never been documented, making this the most reliable choice. 1
Amoxicillin is equally effective and often preferred for young children due to better palatability and the option for once-daily dosing at 50 mg/kg (maximum 1000 mg) for 10 days. 1, 2 This broader-spectrum agent may enhance adherence while remaining relatively inexpensive. 1
Intramuscular benzathine penicillin G (1.2 million units as a single dose) should be used for patients unlikely to complete a full 10-day oral course, particularly in settings where compliance cannot be assured, such as crowded inner-city populations with episodic medical care. 2, 3
Treatment for Penicillin-Allergic Patients
The approach depends on the type of allergic reaction:
For non-anaphylactic penicillin allergy:
- First-generation cephalosporins (cephalexin or cefadroxil) for 10 days are recommended. 1, 2, 4
- Narrow-spectrum cephalosporins are strongly preferred over broad-spectrum agents to minimize selection of antibiotic-resistant flora. 1
- Note that up to 10% of penicillin-allergic patients may also be allergic to cephalosporins. 1
For anaphylactic penicillin allergy:
- Clindamycin for 10 days (resistance rate approximately 1% in the United States). 1, 2, 4
- Clarithromycin for 10 days. 1, 2, 4
- Azithromycin for 5 days (12 mg/kg/day, maximum 500 mg). 1, 2, 4
Important caveat: Macrolide resistance (azithromycin, clarithromycin) ranges from 5-8% in most U.S. areas but can be highly prevalent in some regions, potentially resulting in treatment failures. 1, 2, 4 Despite FDA approval, azithromycin shows significantly lower bacteriologic eradication rates (31-38%) compared to penicillin (68-81%) at Day 28, though clinical success rates remain similar. 5, 6
Adjunctive Symptomatic Treatment
Acetaminophen or NSAIDs should be used for moderate to severe symptoms or high fever control, as multiple randomized, double-blind, placebo-controlled studies demonstrate significant benefits in reducing fever and pain. 1, 2, 7
Aspirin must be avoided in children due to the risk of Reye syndrome. 1, 2, 7, 4
Corticosteroids are not recommended for routine use, as they provide only minimal symptom reduction (approximately 5 hours) with potential adverse effects. 1, 2, 7, 4
Management of Recurrent GAS Pharyngitis
First, distinguish between true recurrent infections versus chronic carriage with superimposed viral infections. 2, 4 Each episode should be confirmed with rapid antigen detection test (RADT) or throat culture. 4
For documented recurrent GAS pharyngitis after penicillin failure, clindamycin for 10 days is highly effective, protecting patients from recurrence for at least 3 months and potentially serving as an alternative to tonsillectomy. 8 Other options include amoxicillin-clavulanic acid or benzathine penicillin G with rifampin. 2
Critical Pitfalls to Avoid
Do not prescribe antibiotics without confirming GAS infection via RADT or throat culture, as viral pharyngitis accounts for 70-85% of cases. 2, 7 Clinical features suggesting viral etiology include cough, rhinorrhea, hoarseness, oral ulcers, conjunctivitis, and diarrhea. 2
Do not use short-course cephalosporins (5-day courses of cefdinir or cefpodoxime) despite FDA approval, as studies lack strict entry criteria and proper assessment of treatment failure versus reinfection. 1
Avoid tetracyclines, sulfonamides, trimethoprim-sulfamethoxazole, and older fluoroquinolones as they are ineffective against GAS. 1
Do not routinely test or treat asymptomatic household contacts, as this provides limited benefit and contributes to antibiotic resistance. 1
Ensure completion of the full 10-day course of penicillin or amoxicillin, as incomplete treatment can lead to treatment failure and increased risk of rheumatic fever. 2, 9
Expected Clinical Response
Clinical improvement typically occurs within 24-48 hours of initiating appropriate antibiotic therapy. 1 Early treatment reduces symptom duration to less than 24 hours in most cases, decreases suppurative complications, and limits disease spread. 3 Routine follow-up throat cultures or RADT are not recommended except in special circumstances. 1