What is the treatment for acute bacterial tonsillitis?

Treatment of Acute Bacterial Tonsillitis

Penicillin V for 10 days is the first-line antibiotic treatment for acute bacterial tonsillitis caused by Group A Streptococcus, with amoxicillin as an equally acceptable alternative. 1, 2, 3

Confirming Bacterial Infection Before Treatment

• Testing with rapid antigen detection test (RADT) and/or throat culture for Group A Streptococcus is mandatory before initiating antibiotics 2, 3
• Bacterial tonsillitis presents with sudden onset of sore throat, fever >38°C (>38.3°C for some criteria), tonsillar exudates, tender anterior cervical lymphadenopathy, and notably the absence of cough 2, 3
• Initiating antibiotics without confirming GAS infection is a critical pitfall to avoid, as most tonsillitis is viral and does not require antibiotics 2, 4

First-Line Antibiotic Regimens

Penicillin V (Preferred)

• Children: 250 mg twice daily or three times daily for 10 days 1
• Adolescents and adults: 250 mg four times daily or 500 mg twice daily for 10 days 1
• Penicillin V is recommended due to proven efficacy, safety, narrow spectrum, low cost, and minimal resistance development 5, 1

Amoxicillin (Equally Acceptable Alternative)

• Children: 50 mg/kg once daily (maximum 1000 mg) for 10 days, or 25 mg/kg (maximum 500 mg) twice daily for 10 days 1
• Amoxicillin offers comparable efficacy to penicillin with the advantage of less frequent dosing, improving compliance 5, 1

Benzathine Penicillin G (Single-Dose Option)

• Patients <27 kg: 600,000 units intramuscularly as a single dose 1
• Patients ≥27 kg: 1,200,000 units intramuscularly as a single dose 1
• This option is particularly useful when compliance with oral therapy is a concern 1

Treatment Duration: Why 10 Days Matters

• The standard 10-day course is necessary to maximize bacterial eradication and prevent serious complications like rheumatic fever 2, 3
• Shorter courses of penicillin (less than 10 days) increase the risk of treatment failure and should be avoided 5, 2
• While some newer antibiotics show efficacy with shorter courses, the clinical differences are small and not clinically significant enough to abandon the proven 10-day regimen for penicillins 5

Treatment for Penicillin-Allergic Patients

For Non-Immediate Hypersensitivity (Type IV Reactions)

• Cephalexin: 20 mg/kg/dose twice daily (maximum 500 mg/dose) for 10 days 1
• Cefadroxil: 30 mg/kg once daily (maximum 1 g) for 10 days 1
• Avoid cephalosporins in patients with immediate-type (IgE-mediated) hypersensitivity to penicillin 1, 3

For Immediate Hypersensitivity or Cephalosporin Allergy

• Clindamycin: 7 mg/kg/dose three times daily (maximum 300 mg/dose) for 10 days 1, 3
• Azithromycin: 12 mg/kg once daily (maximum 500 mg) for 5 days 1, 6
• Clarithromycin: 7.5 mg/kg/dose twice daily (maximum 250 mg/dose) for 10 days 1

Important Caveat About Macrolides

• Macrolide resistance in Group A Streptococcus is a significant concern and varies by geographic region 1
• Azithromycin showed superior bacteriologic eradication compared to penicillin V in pediatric studies (95% vs 73% at Day 14), though approximately 1% of susceptible isolates developed resistance following therapy 6
• Despite shorter treatment duration (5 days), azithromycin demonstrated clinical success rates of 98% at Day 14 compared to 84% for penicillin V 6

Cephalosporins: A Note on Efficacy

• Some meta-analyses show cephalosporins have higher clinical cure rates than penicillin, though the clinical significance of this difference is debated and the magnitude is small 5, 1
• The differences are not clinically relevant enough to displace penicillin as first-line therapy, particularly given cost and spectrum considerations 5

Management of Treatment Failure

• Consider alternative antibiotics such as clindamycin or amoxicillin-clavulanate for patients who fail initial therapy 2
• Treatment failure may indicate beta-lactamase producing co-pathogens, poor compliance, or reinfection 7
• Re-testing for GAS and evaluating for complications such as peritonsillar abscess is warranted 2

Critical Pitfalls to Avoid

• Never use shorter courses of penicillin (<10 days) for GAS tonsillitis - this increases treatment failure risk 2
• Never prescribe broad-spectrum antibiotics when narrow-spectrum penicillins are effective - this promotes unnecessary resistance 2
• Never prescribe antibiotics for viral tonsillitis - most tonsillitis is viral and requires only supportive care with analgesia and hydration 2, 4
• Never initiate antibiotics without confirming GAS infection through testing - clinical presentation alone cannot reliably distinguish bacterial from viral etiology 2, 8