What is the recommended treatment for pneumonia in a 9-year-old patient with a Penicillin (PCN) allergy?

Treatment of Pneumonia in a 9-Year-Old with Penicillin Allergy

For a 9-year-old child with pneumonia and penicillin allergy, a macrolide antibiotic such as azithromycin is the recommended first-line treatment. 1, 2

Antibiotic Selection Algorithm

Outpatient Management

1. First-line therapy:

   • Azithromycin: 10 mg/kg on day 1 (maximum 500 mg), followed by 5 mg/kg once daily on days 2-5 (maximum 250 mg) 1, 2

2. Alternative options (if azithromycin cannot be used):

   • Clarithromycin: 15 mg/kg/day divided in 2 doses (maximum 1 g/day) 1, 2
   • Doxycycline: Can be used since the child is >7 years old, 2-4 mg/kg/day in 2 doses 2
   • Oral cephalosporins with substantial activity against S. pneumoniae (if non-severe penicillin allergy):
     • Cefpodoxime
     • Cefprozil
     • Cefuroxime 1

Inpatient Management (if required)

1. If moderate to severe illness:
   • Azithromycin IV plus one of the following (if non-anaphylactic penicillin allergy):
     • Ceftriaxone or cefotaxime 1
   • If severe penicillin allergy with risk of cross-reactivity:
     • Levofloxacin (for children who have reached growth maturity) 1
     • Clindamycin (if susceptible) 1
     • Linezolid 1

Treatment Considerations Based on Pneumonia Type

Presumed Bacterial Pneumonia

• For a 9-year-old (≥5 years), macrolide antibiotics are appropriate first-line therapy due to:
  • Higher prevalence of Mycoplasma pneumoniae in this age group 1, 2
  • Penicillin allergy preventing use of first-line beta-lactams 1

Presumed Atypical Pneumonia

• Macrolides are the treatment of choice for atypical pneumonia regardless of penicillin allergy status 1, 2
• Azithromycin has shown excellent efficacy against Mycoplasma pneumoniae with 100% eradication rates compared to 57% with erythromycin 3

Duration of Therapy

• Azithromycin: 5-day course (10 mg/kg on day 1, followed by 5 mg/kg on days 2-5) 1, 2, 4
• A 3-day course of azithromycin may be sufficient for mild cases of atypical pneumonia 5

Clinical Pearls and Pitfalls

Important Considerations

• Penicillin allergy label is associated with worse clinical outcomes in bacterial pneumonia, including higher risks of hospitalization (RR 1.23), respiratory failure (RR 1.14), and mortality (RR 1.08) 6
• Azithromycin has been shown to have fewer side effects than erythromycin (11.3% vs 31%) 3
• For children with bacteremic pneumococcal pneumonia, particular caution should be exercised when selecting alternatives to beta-lactams due to risk of secondary sites of infection 1

Monitoring

• Assess clinical response within 48-72 hours of starting therapy 2
• If the child remains febrile or unwell 48 hours after starting treatment, re-evaluation is necessary to consider complications 1
• Patients on oxygen therapy should have oxygen saturation monitored at least every 4 hours 1

Common Mistakes to Avoid

• Inappropriate use of broad-spectrum antibiotics when narrower options would be effective
• Failure to consider local resistance patterns when selecting therapy
• Not considering the possibility of MRSA in severe or non-responding cases (add vancomycin or clindamycin if suspected) 1, 2
• Overlooking the possibility of viral pneumonia, particularly during influenza season

Azithromycin has demonstrated excellent efficacy in both classic and atypical pneumonia, with studies showing faster radiological improvement compared to amoxicillin (81% vs 60.9% at day 7) and earlier cessation of cough compared to erythromycin (3.6 vs 5.5 days) 7.