Treatment for Strep Throat in Patients with Azithromycin and Penicillin Allergies
For patients with allergies to both azithromycin and penicillin, clindamycin is the recommended first-line treatment for strep throat, with clarithromycin as an alternative option. 1
Recommended Antibiotic Options
First-Line Treatment:
- Clindamycin
- Adult dosage: 300 mg three times daily for 10 days
- Pediatric dosage: 6.5 mg/kg body weight twice daily for 10 days
- Clindamycin has demonstrated excellent efficacy in eradicating Group A Streptococcus, even in cases where penicillin treatment has failed 2
Alternative Option:
- Clarithromycin
- This macrolide antibiotic is structurally different from azithromycin and may be tolerated despite azithromycin allergy 1
- Dosage should follow standard recommendations for strep throat treatment
Diagnostic Considerations
Before initiating treatment, confirm the diagnosis using:
- Centor Criteria assessment (tonsillar exudates, tender anterior cervical lymph nodes, lack of cough, and fever)
- Rapid antigen detection test (RADT) and/or throat culture for patients with 3-4 Centor criteria 1
Treatment Considerations
Duration of Treatment
- Complete the full 10-day course of antibiotics to:
- Prevent acute rheumatic fever
- Ensure complete eradication of Group A Streptococcus
- Reduce risk of treatment failure 1
Symptomatic Relief
While antibiotics address the infection, symptomatic treatment is important:
- NSAIDs or acetaminophen for pain and fever management
- Warm salt water gargles and throat lozenges to alleviate throat discomfort 1
Important Caveats and Considerations
Cross-Reactivity Concerns
- Patients with true anaphylactic reactions to penicillin should avoid all β-lactam antibiotics
- Clarithromycin may have cross-reactivity with azithromycin in some patients, so monitor carefully if this alternative is used
Treatment Failure
- If treatment failure occurs with clindamycin (which is rare), consultation with an infectious disease specialist is recommended
- Bacterial culture with susceptibility testing should be performed to guide alternative therapy
Compliance Importance
- Poor compliance is a major factor in treatment failure
- Emphasize to patients the importance of completing the full course of antibiotics even if symptoms improve 3
Special Populations
- For patients with a history of rheumatic fever, continuous antimicrobial prophylaxis may be needed to prevent recurrences 1
- Consider tonsillectomy for patients with recurrent streptococcal tonsillitis based on Paradise criteria (≥7 episodes in one year, ≥5 episodes per year for two years, or ≥3 episodes per year for three years) 1