What is the appropriate evaluation and management for an otherwise healthy patient presenting with acute pharyngitis?

Management of Acute Pharyngitis

Do not prescribe antibiotics based on clinical appearance alone—perform laboratory testing to confirm Group A streptococcal (GAS) pharyngitis before initiating antimicrobial therapy, because viruses cause the majority of acute pharyngitis cases and only GAS infection warrants antibiotic treatment. 1

Initial Clinical Assessment

Determine whether testing is indicated:

• Test when present: Sudden-onset severe sore throat, fever, tonsillopharyngeal erythema with or without exudates, tender anterior cervical lymphadenopathy, absence of cough, palatal petechiae, or scarlatiniform rash 1

• Do NOT test when present: Cough, rhinorrhea, hoarseness, conjunctivitis, oral ulcers, or diarrhea—these features strongly indicate viral etiology and testing will only identify asymptomatic GAS carriers 1, 2

• Age-specific exclusion: Children under 3 years should not be routinely tested unless an older sibling has confirmed GAS infection, because GAS pharyngitis and acute rheumatic fever are rare in this age group 2

Diagnostic Strategy

For Children and Adolescents (Ages 3-18)

Two-step testing is mandatory:

1. Perform rapid antigen detection test (RADT) first 1, 2
2. If RADT is negative, obtain throat culture because RADT sensitivity is only 80-90%, missing 10-20% of true infections 1, 2
3. If culture returns positive, antibiotics can be initiated—treatment within 9 days of symptom onset still prevents acute rheumatic fever 2

For Adults

RADT alone is sufficient:

• A negative RADT does NOT require backup throat culture 1, 2
• This approach is justified because adults have only 5-10% prevalence of GAS pharyngitis and extremely low risk of acute rheumatic fever 2
• RADT specificity is ≥95%, making false positives rare 2

Treatment of Confirmed GAS Pharyngitis

First-Line Therapy (10-Day Course Required)

Penicillin or amoxicillin remains the definitive first-line treatment because of proven efficacy, narrow spectrum, safety, and low cost 1, 2:

• Penicillin V: 250 mg 2-3 times daily for patients <27 kg; 500 mg 2-3 times daily for patients ≥27 kg 2
• Amoxicillin: 50 mg/kg once daily (maximum 1 g)—often preferred in young children due to better taste 1, 2
• Benzathine penicillin G (IM): Single dose of 600,000 U for patients <27 kg; 1,200,000 U for patients ≥27 kg—use when adherence is questionable 1, 2

Penicillin-Allergic Patients

Non-anaphylactic allergy:

• First-generation cephalosporin for 10 days 1, 2

Anaphylactic or immediate-type hypersensitivity:

• Clindamycin: 20 mg/kg/day divided 3 times daily (maximum 1.8 g/day) for 10 days 2
• Azithromycin: 12 mg/kg once daily (maximum 500 mg) for 5 days 2
• Clarithromycin: 15 mg/kg/day divided 2 times daily for 10 days 2

Management of Negative Test Results

Withhold antibiotics entirely and provide only symptomatic treatment because the vast majority of these cases are viral and self-limited 1, 2:

• Analgesics/antipyretics: Ibuprofen or acetaminophen for pain and fever relief 2
• Reassurance: Symptoms typically resolve in less than 1 week without antibiotics 2
• Antibiotics shorten symptom duration by only 1-2 days with number needed to treat of 6 at 3 days and 21 at 1 week 2

Critical Pitfalls to Avoid

Do not treat asymptomatic household contacts:

• Up to one-third of household members may be asymptomatic GAS carriers, but prophylactic treatment does not reduce subsequent infection rates 1, 2

Do not perform routine follow-up testing after completing therapy:

• Follow-up cultures or RADTs are not recommended in asymptomatic patients who completed appropriate antibiotic treatment 1, 2
• Positive post-treatment tests often reflect carrier status rather than treatment failure 2

Do not use clinical scoring alone to prescribe antibiotics:

• Even with Centor score of 4, the actual probability of GAS ranges from only 40-60% in pediatric populations, meaning 40-60% would receive unnecessary antibiotics without testing 2
• Clinical features and exudates overlap too broadly between bacterial and viral causes to make accurate diagnosis without laboratory confirmation 1, 2

Do not shorten antibiotic course below 10 days:

• A full 10-day course is essential to prevent acute rheumatic fever and achieve maximal pharyngeal eradication of GAS 1, 2

Outcomes Prioritized by This Approach

The primary goals are prevention of acute rheumatic fever, prevention of suppurative complications (peritonsillar abscess, cervical lymphadenitis, mastoiditis), symptom abatement, reduced transmission, and minimization of inappropriate antimicrobial therapy 1