What is the recommended treatment for Group A strep (Streptococcus pyogenes) tonsillitis?

Treatment of Group A Streptococcal Tonsillitis

For patients with Group A streptococcal (GAS) tonsillitis, penicillin or amoxicillin remains the first-line treatment of choice due to their proven efficacy, safety, narrow spectrum of activity, and low cost. 1, 2

First-Line Treatment Options (No Penicillin Allergy)

Preferred Regimens:

• Penicillin V (oral):

  • Children: 250 mg 2-3 times daily for 10 days
  • Adolescents/Adults: 250 mg 4 times daily or 500 mg twice daily for 10 days 1, 2

• Amoxicillin (oral):

  • 50 mg/kg once daily (maximum 1000 mg) for 10 days
  • Alternative: 25 mg/kg twice daily (maximum 500 mg per dose) for 10 days 1, 2
  • Advantage: Once-daily dosing may improve adherence

• Benzathine Penicillin G (intramuscular):

  • <27 kg: 600,000 units as a single dose
  • ≥27 kg: 1,200,000 units as a single dose 1
  • Consider for: Patients with poor adherence or inability to take oral medications

Alternative Treatment Options (Penicillin Allergy)

For Non-Anaphylactic Penicillin Allergy:

• Cephalexin (oral):

  • 20 mg/kg twice daily (maximum 500 mg per dose) for 10 days 1, 2

• Cefadroxil (oral):

  • 30 mg/kg once daily (maximum 1 g) for 10 days 1, 2

For Anaphylactic Penicillin Allergy:

• Clindamycin (oral):

  • 7 mg/kg 3 times daily (maximum 300 mg per dose) for 10 days 1, 2

• Azithromycin (oral):

  • 12 mg/kg once daily (maximum 500 mg) for 5 days 1, 2, 3
  • Caution: GAS resistance to macrolides is well-documented (up to 5% in the US) 2

• Clarithromycin (oral):

  • 7.5 mg/kg twice daily (maximum 250 mg per dose) for 10 days 1, 2
  • Caution: Similar resistance concerns as azithromycin

Treatment Duration

The Infectious Diseases Society of America (IDSA) strongly recommends a 10-day duration for most antibiotics to achieve maximal pharyngeal eradication of GAS and prevent complications such as acute rheumatic fever 1, 2. While some studies have explored shorter treatment courses 4, the 10-day regimen remains the standard recommendation for penicillins due to:

1. Consistent evidence of effectiveness
2. Prevention of acute rheumatic fever
3. No documented penicillin resistance in GAS 1, 2

Clinical Considerations

Treatment Efficacy

• Penicillin has been the mainstay of treatment since the 1950s, though some studies report increasing failure rates (up to 30%) 5
• Azithromycin has shown comparable clinical efficacy to penicillin in some studies (clinical success rates of 94-98% for azithromycin vs. 74-84% for penicillin) 3, 6
• Bacteriologic eradication rates with azithromycin can be higher than penicillin in some studies (95% vs. 73% at day 14) 3

Symptom Management

• Patients typically become non-contagious after 24 hours of antibiotic therapy 2
• Clinical response usually occurs within 24-48 hours of starting treatment 2
• Acetaminophen or ibuprofen can be used for pain and fever control (avoid aspirin in children due to risk of Reye syndrome) 2

Follow-Up and Complications

• Routine follow-up throat cultures or rapid antigen detection tests are not recommended 2
• Complete the full course of antibiotics even if symptoms resolve quickly 2
• If symptoms persist or worsen after 5 days of appropriate treatment, consider:
  • Non-compliance with prescribed regimen
  • Penicillin treatment failure
  • New GAS infection
  • Viral pharyngitis in a GAS carrier 2

Special Considerations

GAS Carriers

• GAS carriers do not ordinarily require identification or antimicrobial therapy 1
• Carriers are unlikely to spread GAS pharyngitis to close contacts and are at minimal risk for developing complications 1

Tonsillectomy

• Tonsillectomy is not recommended solely to reduce the frequency of GAS pharyngitis 1
• Consider only if patient meets Paradise criteria (≥7 episodes in past year, or ≥5 episodes per year for 2 consecutive years, or ≥3 episodes per year for 3 consecutive years) 2

Common Pitfalls to Avoid

1. Undertreatment: Insufficient duration of therapy may lead to treatment failure and complications
2. Poor adherence: The 10-day course can be challenging; consider once-daily amoxicillin to improve compliance
3. Inappropriate use of macrolides: Using azithromycin or clarithromycin in areas with high GAS resistance
4. Unnecessary tonsillectomy: Surgery should not be performed solely to prevent recurrent GAS pharyngitis
5. Treating viral pharyngitis: Ensure proper diagnosis of GAS infection before initiating antibiotics