Diagnosis and Treatment of Group A Streptococcal Pharyngitis in Children and Adolescents
Diagnostic Approach
In children aged 5–15 years with acute pharyngitis, perform a rapid antigen detection test (RADT) first; if negative, obtain a backup throat culture before making final treatment decisions. 1
Do not test children younger than 3 years unless an older sibling has confirmed GAS infection, because acute rheumatic fever and classic streptococcal pharyngitis are rare in this age group. 1
Do not test when clear viral features are present—cough, rhinorrhea, hoarseness, conjunctivitis, or oral ulcers strongly indicate viral etiology and testing will likely identify asymptomatic carriers rather than true infection. 1
Test when clinical features suggest bacterial infection: sudden-onset sore throat, fever, tonsillar exudates, tender anterior cervical lymphadenopathy, and absence of viral symptoms. 1
Two-Step Testing Algorithm for Children
Positive RADT: No backup culture needed; specificity is ≥95%, making false positives rare. 1
Negative RADT: Mandatory backup throat culture because RADT sensitivity is only 80–90% in children, missing 10–20% of true infections. 1, 2, 3
The higher prevalence of GAS (20–30%) in children aged 5–15 years and the meaningful risk of acute rheumatic fever justify this two-step approach. 1
Treatment can be initiated when the culture returns positive—therapy started within 9 days of symptom onset still effectively prevents acute rheumatic fever. 1
Common Diagnostic Pitfall
- RADT sensitivity increases with disease severity (spectrum bias): 47% in children with zero Centor criteria versus 90% in those with 3–4 criteria, but even with high clinical scores, backup culture remains mandatory in children. 3
First-Line Antibiotic Therapy
Prescribe oral amoxicillin 50 mg/kg once daily (maximum 1000 mg) or 25 mg/kg twice daily (maximum 500 mg per dose) for a full 10-day course. 1, 4
Why Amoxicillin is Preferred
Zero documented penicillin resistance exists worldwide among Group A Streptococcus, guaranteeing reliable bacterial eradication. 1, 4
Amoxicillin offers better palatability and more convenient dosing than penicillin V in children, improving adherence while maintaining identical efficacy. 5
Its narrow antimicrobial spectrum minimizes disruption to normal flora and reduces selection pressure for resistant organisms. 4
Proven efficacy in preventing acute rheumatic fever, the primary goal of treatment. 4
Critical Treatment Duration
A complete 10-day course is mandatory to achieve maximal pharyngeal eradication and prevent acute rheumatic fever; shortening the course by even 2–3 days markedly increases treatment failure and rheumatic fever risk. 1, 5, 4
- Even when symptoms resolve within 3–4 days, the full 10-day regimen must be continued because premature discontinuation permits bacterial regrowth. 5
Alternative: Intramuscular Benzathine Penicillin G
Single IM dose: 600,000 units for children <27 kg; 1.2 million units for children ≥27 kg. 1
Use when oral adherence is uncertain—this eliminates compliance concerns entirely. 1
Management of Penicillin-Allergic Patients
Non-Anaphylactic (Delayed) Penicillin Allergy
Prescribe a first-generation cephalosporin: cephalexin 20 mg/kg twice daily (maximum 500 mg per dose) for 10 days. 1, 5, 4
Cross-reactivity risk with delayed, mild penicillin reactions is only 0.1%, making cephalosporins safe and preferred. 1, 5
First-generation cephalosporins have strong, high-quality evidence supporting their efficacy, narrow spectrum, and low cost. 5, 4
Immediate/Anaphylactic Penicillin Allergy
All β-lactam antibiotics must be avoided because cross-reactivity can reach 10% in patients with immediate hypersensitivity (anaphylaxis, angioedema, urticaria within 1 hour). 1, 5
Prescribe clindamycin 7 mg/kg three times daily (maximum 300 mg per dose) for 10 days. 1, 5, 4
Clindamycin is the preferred β-lactam-free alternative with only ~1% resistance among US Group A Streptococcus isolates. 1, 5
It demonstrates superior eradication rates even in chronic carriers and treatment failures. 1, 5
Macrolide Alternatives (Less Preferred)
Azithromycin: 12 mg/kg once daily (maximum 500 mg) for 5 days—the only antibiotic requiring a shortened course due to prolonged tissue half-life. 1, 5
Clarithromycin: 7.5 mg/kg twice daily (maximum 250 mg per dose) for 10 days. 1, 5
Macrolide resistance in the United States ranges from 5–8% and varies geographically, making clindamycin more reliable. 1, 5, 4
Critical Pitfalls to Avoid
Do not prescribe antibiotics without laboratory confirmation—clinical features alone cannot reliably distinguish bacterial from viral pharyngitis, and most cases are viral. 1
Do not use cephalosporins in patients with immediate/anaphylactic penicillin reactions due to the ~10% cross-reactivity risk. 1, 5
Do not shorten the antibiotic course below 10 days (except azithromycin's 5-day regimen), as this dramatically increases treatment failure and rheumatic fever risk. 1, 5, 4
Do not test or treat asymptomatic household contacts—up to one-third may be carriers, and prophylactic treatment does not reduce subsequent infection rates. 1
Do not order routine post-treatment cultures for asymptomatic children who completed therapy; reserve testing for special circumstances such as prior rheumatic fever. 1, 5
Do not prescribe trimethoprim-sulfamethoxazole (Bactrim)—it fails to eradicate GAS in 20–25% of cases and is absolutely contraindicated. 5
Adjunctive Symptomatic Management
Offer acetaminophen or ibuprofen for moderate-to-severe sore throat, fever, or systemic discomfort. 1, 4
Avoid aspirin in children due to the risk of Reye syndrome. 1, 5, 4
Corticosteroids are not recommended as adjunctive therapy for streptococcal pharyngitis. 1, 5, 4
Management of Treatment Failure
If symptoms persist after a fully adhered 10-day course, switch to clindamycin 7 mg/kg three times daily (maximum 300 mg per dose) for 10 days. 1, 5
Clindamycin achieves substantially higher eradication rates than penicillin or amoxicillin in chronic carriers and persistent infections. 1, 5
Consider whether the patient is a chronic GAS carrier experiencing concurrent viral infections rather than true recurrent streptococcal infections—carriers generally do not require treatment. 1