Treatment of Strep Throat in Children with Penicillin Allergy
For children with penicillin allergy and strep throat, azithromycin is the recommended alternative treatment at a dosage of 12 mg/kg once daily for 5 days (maximum 500 mg per dose). 1
First-Line Alternative Options
When penicillin allergy prevents the use of first-line therapy (penicillin V or amoxicillin), the following alternatives should be considered:
Azithromycin
- Dosage: 12 mg/kg once daily (maximum 500 mg per dose)
- Duration: 5 days
- Advantages: Once-daily dosing improves compliance 1, 2
Clindamycin
- Dosage: 20-30 mg/kg/day divided into 3 doses (maximum 300-450 mg per dose)
- Duration: 10 days
- Best for: Severe penicillin allergies or cases where macrolides cannot be used 1
Efficacy Considerations
While azithromycin offers convenient dosing, it's important to note that:
- The FDA label indicates azithromycin has shown 95% bacteriologic eradication of S. pyogenes at Day 14, compared to 73% with penicillin V 3
- However, some studies show lower eradication rates with azithromycin (10 mg/kg for 3 days) compared to penicillin V (65% vs. 82%) 4
- A total dose of 60 mg/kg azithromycin (either as 12 mg/kg daily for 5 days or 20 mg/kg daily for 3 days) provides optimal eradication rates 5
Treatment Monitoring
- Evaluate for treatment failure if symptoms worsen or don't improve after 48-72 hours of antibiotic therapy 1
- Consider potential causes of treatment failure:
- Non-compliance with prescribed regimen
- Streptococcal carrier with concurrent viral infection
- New infection with Group A Streptococcus
- True treatment failure (rare) 1
Important Considerations
- Allergy severity: The choice between azithromycin and clindamycin may depend on the severity of the penicillin allergy 1
- Resistance concerns: Some strains of S. pyogenes may be resistant to azithromycin, so susceptibility testing should be performed when possible 3
- Rheumatic fever prevention: Unlike penicillin, data establishing azithromycin's efficacy in preventing rheumatic fever are not available 1, 3
Supportive Care
- Manage pain and fever with NSAIDs or acetaminophen (avoid aspirin due to risk of Reye syndrome) 1
- Consider symptomatic relief with:
- Cold liquids and ice chips
- Gargling with cold water
- Avoiding hot liquids and spicy foods 1
Remember that while azithromycin is effective and well-tolerated with the convenience of a short, once-daily regimen 2, the 5-day course at 12 mg/kg/day is preferred over shorter courses to ensure adequate eradication of the pathogen 1, 5.