A patient presents with sore throat, fever, tonsillar exudates, tender anterior cervical lymphadenopathy, and no cough—how should I evaluate for group A Streptococcus and manage tonsillopharyngitis?

Evaluation and Management of Tonsillopharyngitis

Initial Clinical Assessment

Use the modified Centor criteria to determine who needs testing: this patient scores 4 points (fever + exudates + tender anterior cervical nodes + no cough), making group A Streptococcus highly likely and mandating immediate rapid antigen detection testing. 1

Modified Centor Scoring

• Fever by history: 1 point 1
• Tonsillar exudates: 1 point 1
• Tender anterior cervical adenopathy: 1 point 1
• Absence of cough: 1 point 1
• Total score = 4 points (51-53% probability of GAS) 2

Testing Algorithm Based on Score

• Score ≥3: Perform rapid antigen detection test (RADT) immediately 1
• Score <3: No testing needed—treat symptomatically only 1
• Do not test if viral features present (cough, rhinorrhea, conjunctivitis, hoarseness, oral ulcers) 1, 2

Diagnostic Testing Strategy

Adults

• Positive RADT: Treat with antibiotics—no confirmatory culture needed (specificity ≥95%) 1, 2
• Negative RADT: No backup throat culture required in adults—withhold antibiotics entirely 1, 2
• The 5-10% prevalence of GAS in adults and extremely low risk of acute rheumatic fever justify accepting the 10-20% false-negative rate 2

Children and Adolescents

• Positive RADT: Treat with antibiotics—no confirmatory culture needed 1, 2
• Negative RADT: Must send backup throat culture before final treatment decision 1, 2
• RADT sensitivity is only 80-90% in children, missing 10-20% of true infections 2
• Treatment can be initiated when culture returns positive—starting within 9 days of symptom onset still prevents acute rheumatic fever 2

First-Line Antibiotic Therapy for Confirmed GAS

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

Preferred Regimens (10-day duration)

• Penicillin V: 250 mg 2-3 times daily (children <27 kg); 500 mg 2-3 times daily (≥27 kg and adults) 1, 2
• Amoxicillin: 50 mg/kg once daily (maximum 1 g) 1, 2
• Benzathine penicillin G (IM): Single dose of 600,000 U (<27 kg) or 1,200,000 U (≥27 kg)—use when adherence is a concern 2

Penicillin-Allergic Patients

• Non-anaphylactic allergy: First-generation cephalosporin for 10 days 1
• Anaphylactic/immediate hypersensitivity:
  • Clindamycin 20 mg/kg/day divided 3 times daily (maximum 1.8 g/day) for 10 days 1, 2
  • Azithromycin 12 mg/kg once daily (maximum 500 mg) for 5 days 1, 2
  • Clarithromycin 15 mg/kg/day divided twice daily for 10 days 2

Management of Negative Test Results

Withhold antibiotics entirely when GAS testing is negative—provide only symptomatic therapy because the vast majority of these cases are viral and self-limited. 1, 2

Symptomatic Treatment

• Ibuprofen or acetaminophen for pain and fever relief 1, 2
• Throat lozenges for comfort (avoid in young children due to choking hazard) 1, 2
• Warm salt water gargles (for patients old enough to gargle) 1
• Reassure that symptoms typically resolve in less than 1 week 2

Expected Antibiotic Benefit (When GAS-Positive)

• Antibiotics shorten sore throat duration by only 1-2 days 1
• Number needed to treat: 6 at 3 days, 21 at 1 week 1
• Primary benefit is preventing acute rheumatic fever, not symptom relief 1, 2

Critical Pitfalls to Avoid

Do Not Treat Based on Clinical Appearance Alone

• Physicians overestimate GAS probability by 80-95% 3
• Exudates and white patches occur with viral infections and do not reliably distinguish bacterial from viral causes 2, 4
• Up to 70% of patients with sore throats receive unnecessary antibiotics, while only 20-30% have GAS 2, 5

Do Not Test or Treat Asymptomatic Contacts

• Up to one-third of household members may be asymptomatic GAS carriers 1, 2
• Prophylactic treatment of contacts does not reduce subsequent infection rates 1, 2
• Testing asymptomatic contacts is not recommended 2

Do Not Perform Routine Follow-Up Testing

• Post-treatment cultures are not recommended in asymptomatic patients after completing appropriate therapy 1, 2
• Positive post-treatment tests often reflect carrier status rather than treatment failure 1, 2

Recognize Chronic Carriers

• Chronic carriers have GAS present but no active immunologic response (no rising antibody titers) 1
• Up to 20% of school-age children may be carriers during winter/spring 1
• Carriers experiencing viral pharyngitis will test positive but do not require antibiotics 1, 2
• Consider carrier state when patients have recurrent positive tests at short intervals 1

Special Considerations

When to Suspect Serious Complications

• Severe symptoms requiring urgent evaluation: difficulty swallowing, drooling, neck tenderness/swelling, severe unilateral throat pain 1
• Consider peritonsillar abscess, parapharyngeal abscess, epiglottitis, or Lemierre syndrome 1
• Fusobacterium necrophorum causes 10-20% of endemic pharyngitis in adolescents and can lead to life-threatening Lemierre syndrome 1

Age-Specific Exclusions

• Children <3 years: Do not test or treat for GAS unless an older sibling has confirmed infection—GAS pharyngitis and acute rheumatic fever are rare in this age group 2

Duration Matters

• 10-day course is mandatory for penicillin to optimize bacterial eradication and prevent rheumatic fever 1, 5
• Shorter penicillin courses (5 days) are inferior and not recommended 6, 5
• Only cefpodoxime and azithromycin have FDA-approved 5-day regimens 5