Antibiotic Treatment for Acute Bacterial Sinusitis in a 12-Year-Old
For a 12-year-old with acute bacterial sinusitis, amoxicillin at 45 mg/kg/day divided into 2 doses (maximum 500 mg twice daily) is the recommended first-line treatment for 7-10 days. 1, 2
First-Line Treatment Options
Standard-dose amoxicillin is appropriate for most cases unless the child has specific risk factors for resistant bacteria. 1, 3 The dose should be 45 mg/kg/day divided into 2 doses, not exceeding 500 mg twice daily. 1, 2
High-dose amoxicillin-clavulanate (80-90 mg/kg/day of amoxicillin component with 6.4 mg/kg/day of clavulanate in 2 divided doses) should be used instead if the child: 1, 2
- Lives in an area with high prevalence of penicillin-resistant Streptococcus pneumoniae
- Attends daycare
- Has received antibiotics within the past 4-6 weeks
- Presents with moderate to severe illness (high fever, severe facial pain)
- Is younger than 2 years (though your patient is 12)
Alternative Options for Penicillin Allergy
If the child has a penicillin allergy, cefpodoxime-proxetil at 8 mg/kg/day in 2 divided doses is the recommended alternative. 1, 2 Other acceptable second- or third-generation cephalosporins include cefuroxime-axetil or cefdinir. 1, 2, 3
Important caveat: Recent evidence shows that the risk of cross-reactivity between penicillins and second/third-generation cephalosporins is negligible, so cephalosporins can be safely used in most patients with reported penicillin allergy. 1
Azithromycin and other macrolides should NOT be used due to high resistance rates among S. pneumoniae and H. influenzae. 2, 4 Despite FDA approval of azithromycin for sinusitis, current guidelines explicitly exclude it from recommended therapy. 2
Treatment Duration
The standard duration is 7-10 days. 1, 2 Some experts recommend continuing treatment until the patient is symptom-free for 7 additional days, which typically results in a 10-14 day total course. 1, 2
When to Escalate or Change Therapy
If there is no improvement after 3-5 days of initial antibiotic therapy, switch to a different antibiotic. 2, 3 The appropriate second-line choice is:
- Amoxicillin-clavulanate (if amoxicillin was used initially) at high-dose: 80-90 mg/kg/day of amoxicillin component 1, 2
- A different cephalosporin (if cephalosporin was used initially) 2
For children unable to tolerate oral medication or unlikely to be adherent, a single dose of intramuscular or intravenous ceftriaxone 50 mg/kg can be given. 1, 2 If the child improves at 24 hours, switch to oral antibiotics to complete the course. 1
Adjunctive Therapies
Intranasal corticosteroids can be added as adjunctive therapy to help reduce mucosal inflammation and improve symptoms. 2 Short-term oral corticosteroids may be considered for severe pain (hyperalgic sinusitis) or marked mucosal edema. 1, 2
Supportive measures include adequate hydration, analgesics, warm facial packs, and sleeping with the head elevated. 2
Critical Pitfalls to Avoid
Do not use fluoroquinolones (levofloxacin, moxifloxacin) as first-line therapy. 1, 2, 5 These should be reserved only for complicated sinusitis involving frontal, ethmoidal, or sphenoidal sinuses, or for treatment failure after appropriate first-line therapy. 1, 2, 5
Do not use ciprofloxacin at all for sinusitis as it has inadequate coverage against S. pneumoniae, the most common pathogen. 5
Avoid macrolides (azithromycin, clarithromycin) due to resistance patterns despite their FDA approval for this indication. 2, 4
Microbiology Context
The predominant pathogens are Streptococcus pneumoniae (30-66%), Haemophilus influenzae (20-30%), and Moraxella catarrhalis (12-28%). 6, 7 Approximately 10-42% of H. influenzae and nearly 100% of M. catarrhalis produce β-lactamase, making them resistant to amoxicillin alone. 3 This is why amoxicillin-clavulanate is preferred in high-risk situations. 1, 2