What is the appropriate management of acute pharyngitis, including when to use antibiotics and the first‑line therapy?

Management of Acute Pharyngitis

For acute pharyngitis, antibiotics should only be prescribed when Group A Streptococcus (GAS) is confirmed by testing—either rapid antigen detection test (RADT) or throat culture—because the vast majority of cases are viral and do not benefit from antimicrobial therapy. 1

When to Test for GAS

• Do not test patients with clear viral features such as cough, rhinorrhea, hoarseness, conjunctivitis, or oral ulcers, as these strongly indicate a viral etiology. 1

• Do not test children younger than 3 years unless special risk factors exist (e.g., an older sibling with confirmed GAS infection), because acute rheumatic fever and classic streptococcal pharyngitis are rare in this age group. 1

• Test patients aged 5–15 years and adults who present with sudden-onset sore throat, fever, tonsillar exudates, tender anterior cervical lymphadenopathy, and absence of viral features. 1, 2

Diagnostic Approach by Age

Children and Adolescents

• Perform a RADT first; if positive, no backup culture is needed (specificity ≥95%). 1, 2
• If the RADT is negative, obtain a backup throat culture because RADT sensitivity is only 80–90% in children, missing 10–20% of true infections. 1, 2

Adults

• A negative RADT alone is sufficient to rule out GAS pharyngitis; backup throat culture is not necessary because adults have a 5–10% prevalence of GAS and extremely low risk of acute rheumatic fever. 1, 2

First-Line Antibiotic Therapy for Confirmed GAS

Penicillin or amoxicillin for 10 days is the definitive first-line treatment, offering narrow-spectrum activity, proven efficacy in preventing acute rheumatic fever, excellent safety, and low cost. 1

Specific Regimens

Adults:

• Penicillin V 250 mg 2–3 times daily or 500 mg twice daily for 10 days 1, 3
• Amoxicillin 50 mg/kg once daily (maximum 1 g) for 10 days 1, 3
• Benzathine penicillin G (IM) 1.2 million units as a single dose if adherence is a concern 1, 3

Children:

• Penicillin V 250 mg 2–3 times daily (<27 kg) or 500 mg 2–3 times daily (≥27 kg) for 10 days 1
• Amoxicillin 50 mg/kg once daily (maximum 1 g) or 25 mg/kg twice daily (maximum 500 mg per dose) for 10 days 1
• Benzathine penicillin G (IM) 600,000 U (<27 kg) or 1.2 million U (≥27 kg) as a single dose 1

Why 10 Days Is Mandatory

• A full 10-day course is essential to achieve maximal pharyngeal eradication of GAS and prevent acute rheumatic fever, even if symptoms resolve within 3–4 days. 1, 2
• Shortening the course by even a few days dramatically increases treatment failure rates and rheumatic fever risk. 1, 2
• Treatment initiated within 9 days of symptom onset still effectively prevents acute rheumatic fever. 1, 2

Management of Penicillin-Allergic Patients

Non-Anaphylactic (Delayed) Penicillin Allergy

• First-generation cephalosporins are the preferred alternative with strong, high-quality evidence. 1, 4
• Cephalexin 20 mg/kg twice daily (maximum 500 mg per dose) for 10 days in children; 500 mg twice daily for 10 days in adults 1, 4
• Cefadroxil 30 mg/kg once daily (maximum 1 g) for 10 days in children; 1 g once daily for 10 days in adults 1, 4
• Cross-reactivity risk is only 0.1% in patients with non-severe, delayed penicillin reactions. 4

Immediate/Anaphylactic Penicillin Allergy

• Avoid all beta-lactams (including cephalosporins) due to up to 10% cross-reactivity risk. 1, 4

Preferred alternative:

• Clindamycin 7 mg/kg three times daily (maximum 300 mg per dose) for 10 days in children; 300 mg three times daily for 10 days in adults 1, 4
• Clindamycin has only ~1% resistance among GAS in the United States and demonstrates superior eradication rates even in chronic carriers. 1, 4

Acceptable alternatives:

• Azithromycin 12 mg/kg once daily (maximum 500 mg) for 5 days in children; 500 mg once daily for 5 days in adults 1, 4
• Clarithromycin 7.5 mg/kg twice daily (maximum 250 mg per dose) for 10 days in children; 250 mg twice daily for 10 days in adults 1, 4
• Macrolide resistance is 5–8% in the United States and varies geographically; clindamycin is more reliable when beta-lactams cannot be used. 1, 4
• Azithromycin is the only antibiotic requiring just 5 days due to its prolonged tissue half-life. 1, 4

Management When Testing Is Negative

• Withhold antibiotics entirely and provide only symptomatic therapy, as the vast majority of negative-test cases are viral and self-limited. 1, 2
• Offer acetaminophen or NSAIDs (e.g., ibuprofen) for moderate to severe symptoms or high fever. 1, 2
• Avoid aspirin in children due to Reye syndrome risk. 1, 2
• Corticosteroids are not recommended as adjunctive therapy. 1, 2

Common Pitfalls to Avoid

• Do not prescribe antibiotics based on clinical appearance alone (e.g., tonsillar exudates or white patches), as these findings occur in both viral and bacterial infections. 1, 2

• Do not test or treat asymptomatic household contacts; up to one-third may be asymptomatic GAS carriers, and prophylactic treatment does not reduce subsequent infection rates. 1, 2

• Do not perform routine follow-up testing after completing therapy in asymptomatic patients; positive post-treatment tests often reflect carrier status rather than treatment failure. 1, 2

• Do not use broad-spectrum cephalosporins (e.g., cefdinir, cefpodoxime) when narrow-spectrum first-generation agents are appropriate, as they are more expensive and promote antibiotic resistance. 1, 4

• Do not prescribe trimethoprim-sulfamethoxazole (Bactrim) for strep throat, as it fails to eradicate GAS in 20–25% of cases. 4

Special Considerations

• Recurrent pharyngitis: Consider chronic GAS carriage with superimposed viral infections rather than repeated true GAS infections; chronic carriers generally do not require treatment. 1, 2

• Treatment failures: If initial therapy with penicillin or amoxicillin fails, clindamycin demonstrates substantially higher eradication rates in chronic carriers and persistent infections. 1, 4