Treatment for 6-Year-Old Boy with Right Lower Lobe Pneumonia and Amoxicillin Allergy
For a 6-year-old with community-acquired pneumonia who is allergic to amoxicillin, azithromycin is the definitive first-line treatment at 10 mg/kg on day 1 (maximum 500 mg), followed by 5 mg/kg/day once daily on days 2-5 (maximum 250 mg/day). 1, 2, 3
Outpatient Management Algorithm
Primary recommendation: Azithromycin provides excellent coverage for both typical bacterial pathogens (Streptococcus pneumoniae) and atypical organisms (Mycoplasma pneumoniae, Chlamydophila pneumoniae), which are increasingly common in children ≥5 years of age. 1, 3
Dosing specifics for azithromycin:
- Day 1: 10 mg/kg as a single dose (maximum 500 mg) 1, 4
- Days 2-5: 5 mg/kg once daily (maximum 250 mg/day) 1, 4
- Can be taken with or without food 4
Alternative oral options if azithromycin cannot be used:
For non-severe penicillin allergy (no anaphylaxis):
- Cefpodoxime, cefprozil, or cefuroxime under medical supervision, as cross-reactivity with cephalosporins occurs in approximately 10% of penicillin-allergic patients 1, 5, 6
- These provide good pneumococcal coverage but require careful monitoring for allergic reactions 1, 5
For severe penicillin allergy (anaphylaxis history):
- Levofloxacin 8-10 mg/kg/day once daily (maximum 750 mg/day) is preferred for severe allergy 1, 2, 5
- Clindamycin 30-40 mg/kg/day in 3-4 divided doses if local pneumococcal susceptibility is known 1, 2
When to Hospitalize
Admit if any of the following are present: 1
- Oxygen saturation ≤92% on room air 1
- Respiratory rate >50 breaths/min 1
- Difficulty breathing or grunting 1
- Signs of dehydration 1
- Inability of family to provide appropriate observation 1
Inpatient Treatment for Penicillin-Allergic Patients
If hospitalization is required:
- Azithromycin IV 10 mg/kg on days 1 and 2, then transition to oral therapy 2, 3, 5
- Add vancomycin 40-60 mg/kg/day divided every 6-8 hours OR clindamycin 10-13 mg/kg/dose IV every 6-8 hours if MRSA is suspected (necrotizing infiltrates, empyema, recent influenza, or severe presentation) 1, 2, 3
For severe allergy with no MRSA concern:
- Levofloxacin or moxifloxacin IV are alternatives with excellent pneumococcal activity 5
Critical Considerations and Common Pitfalls
Do NOT use ciprofloxacin - it lacks adequate pneumococcal coverage and is contraindicated for community-acquired pneumonia 5
Macrolide resistance: While azithromycin is recommended, approximately 1% of S. pneumoniae isolates may develop resistance following therapy 4. However, clinical efficacy remains high at 94-95% 7
Reassessment timing: Evaluate clinical response within 48-72 hours 1, 2, 3. If no improvement occurs, consider:
- Treatment failure due to resistant organisms 3
- Complications such as parapneumonic effusion 1
- Alternative diagnosis 2
Atypical pathogen prevalence: In children ≥5 years, Mycoplasma pneumoniae and Chlamydophila pneumoniae account for approximately 29.5% and 15% of cases respectively, making macrolides particularly appropriate for this age group 7
Safety Profile
Azithromycin has significantly fewer adverse events compared to amoxicillin-clavulanate or erythromycin (11.3% vs 31% treatment-related adverse events), with the most common being gastrointestinal symptoms 7. The 5-day course improves adherence compared to 10-day regimens 7