What is the recommended management for strep (streptococcal) pharyngitis in the Emergency Department (ED)?

Management of Streptococcal Pharyngitis in the Emergency Department

Treat confirmed Group A streptococcal pharyngitis with penicillin V 250 mg orally twice daily for 10 days in children or 500 mg twice daily for 10 days in adults, or give a single intramuscular injection of benzathine penicillin G (600,000 units for patients <27 kg; 1.2 million units for patients ≥27 kg) if compliance is uncertain. 1

Diagnostic Approach

Confirm the diagnosis before initiating antibiotics using either throat culture or rapid antigen detection testing (RADT), as clinical features alone cannot reliably distinguish Group A streptococcal pharyngitis from viral causes 1.

• If clinical suspicion is high based on epidemiological factors (e.g., known outbreak, close contact with confirmed case), you may initiate therapy while awaiting culture results, but discontinue antibiotics if testing is negative 1
• Therapy can be safely delayed up to 9 days after symptom onset and still prevent acute rheumatic fever, so waiting for test confirmation does not compromise outcomes 1

First-Line Antibiotic Selection

Penicillin remains the drug of choice due to its narrow spectrum, proven efficacy in preventing rheumatic fever, lack of resistance, safety profile, and low cost 1. No Group A streptococcal isolate worldwide has ever demonstrated penicillin resistance 1.

Penicillin Regimens:

• Oral penicillin V: 250 mg twice daily for children (or 500 mg twice daily for adults) for 10 days 1
• Amoxicillin: 50 mg/kg once daily (maximum 1000 mg) for 10 days—often preferred in young children due to better palatability and once-daily dosing that may improve adherence 1
• Intramuscular benzathine penicillin G: Single injection of 600,000 units for patients <27 kg or 1.2 million units for patients ≥27 kg 1

Use intramuscular benzathine penicillin G in the ED when:

• Compliance with a 10-day oral course is unlikely 1
• The patient has limited access to follow-up care 2
• The patient lives in areas where rheumatic fever remains prevalent (inner-city populations with episodic medical care) 2

Penicillin-Allergic Patients

For patients with non-anaphylactic penicillin allergy, use a first-generation cephalosporin (cephalexin or cefadroxil) for 10 days, as cross-reactivity risk is <3% 1, 3.

For patients with immediate-type hypersensitivity or anaphylactic reactions to β-lactams:

• Azithromycin: 12 mg/kg once daily (maximum 500 mg) for 5 days 1, 4
• Clarithromycin: Standard dosing for 10 days 1
• Clindamycin: 7 mg/kg three times daily (maximum 300 mg/dose) for 10 days 1, 5

Important Caveat on Macrolides:

While macrolide resistance remains <5% in the United States, it has been reported in isolated cases 1. The FDA label notes that azithromycin is indicated as an alternative to first-line therapy, and data establishing its efficacy in preventing rheumatic fever are not available 4. Despite this limitation, azithromycin is widely used and guideline-endorsed for penicillin-allergic patients 1.

Treatment Duration

Most oral antibiotics require a full 10-day course to achieve maximal pharyngeal eradication of Group A streptococci 1. While the FDA has approved certain agents (cefdinir, cefpodoxime, azithromycin) for 5-day courses, the IDSA guidelines note that these shorter courses use broader-spectrum antibiotics and are more expensive than penicillin 1. A recent 2022 study found that 5- to 7-day courses were non-inferior to 10-day courses for clinical outcomes 6, but the 10-day course remains the standard recommendation in current IDSA guidelines 1.

Key Clinical Outcomes of Treatment

Treatment achieves multiple goals beyond just symptom relief 1:

1. Prevention of acute rheumatic fever (the primary rationale for treatment)
2. Prevention of suppurative complications (peritonsillar abscess, cervical lymphadenitis, mastoiditis)
3. Rapid symptom resolution (within 24-48 hours) 1, 2
4. Decreased infectivity after 24 hours of appropriate therapy 3
5. Reduced transmission to close contacts 1

Post-Treatment Management

Do not perform routine follow-up throat cultures or RADT in asymptomatic patients who have completed therapy 1. Testing is only indicated in special circumstances:

• Patients with persistent or recurrent symptoms 1, 5
• Patients with a history of rheumatic fever 1, 5
• During outbreaks of acute rheumatic fever or post-streptococcal glomerulonephritis 5

Do not routinely test or treat asymptomatic household contacts unless there are repeated episodes suggesting household transmission 1.

Management of Treatment Failure or Recurrence

If symptoms persist or recur shortly after completing therapy with a positive repeat test 1:

• Retreat with clindamycin (7 mg/kg three times daily for 10 days) or amoxicillin-clavulanate, as these agents achieve higher eradication rates in difficult cases 1, 5
• Consider intramuscular benzathine penicillin G if compliance with the initial oral regimen is questionable 1
• Recognize that up to 20% of school-aged children are asymptomatic streptococcal carriers who may develop intercurrent viral infections mimicking pharyngitis 5

Common Pitfalls to Avoid

• Treating without diagnostic confirmation: Leads to unnecessary antibiotic use, adverse effects, and antimicrobial resistance 1
• Using inappropriate antibiotics: Tetracyclines, sulfonamides, trimethoprim-sulfamethoxazole, and older fluoroquinolones are not effective against Group A streptococci 5
• Stopping therapy early: Even though symptoms resolve quickly, the full course is needed to eradicate the organism and prevent rheumatic fever 1
• Routine post-treatment testing: This identifies carriers rather than treatment failures and leads to unnecessary retreatment 1, 5