How should a 12-year-old with acute sinusitis be treated?

Treatment of Acute Bacterial Sinusitis in a 12-Year-Old

Start oral amoxicillin 45 mg/kg/day divided twice daily for 10–14 days (or until symptom-free for 7 days) as first-line therapy. 1

Diagnostic Confirmation

The diagnosis is entirely clinical—do not obtain imaging studies (X-rays or CT scans) for uncomplicated cases, as they do not change management and lack specificity. 1, 2

• A 12-year-old meets criteria for acute bacterial sinusitis if presenting with any of these three patterns: 1
  • Persistent illness: nasal discharge (any quality) or daytime cough lasting >10 days without improvement 1
  • Worsening course: sudden worsening or new fever ≥38°C after initial improvement 1
  • Severe onset: fever ≥39°C plus purulent nasal discharge for ≥3 consecutive days 1

First-Line Antibiotic Regimen

• Standard-dose amoxicillin (45 mg/kg/day divided twice daily) is the recommended first-line agent for uncomplicated acute bacterial sinusitis. 1, 2

• The number needed to treat with antibiotics is 3–5 to achieve clinical cure, demonstrating substantial benefit over observation. 1, 2

• Treatment duration should be 10–14 days total, or continue until the child is symptom-free for at least 7 days. 2, 3

When to Escalate to High-Dose Therapy

Use high-dose amoxicillin (80–90 mg/kg/day) or high-dose amoxicillin-clavulanate if the child has any of these risk factors: 1, 2

• Recent antibiotic use within the past 4–6 weeks 1, 2
• Daycare attendance 1, 2
• Residence in areas with high prevalence of penicillin-resistant Streptococcus pneumoniae 1, 2
• Age <2 years (not applicable to this 12-year-old) 2

Mandatory 72-Hour Reassessment

Re-evaluate the child exactly 72 hours after starting amoxicillin to identify treatment failure or complications: 1, 2, 4

• Worsening symptoms (new fever, increased purulent discharge, severe headache) → escalate immediately to high-dose amoxicillin-clavulanate (90 mg/kg/day of amoxicillin component). 1, 2, 5

• Lack of improvement by 72 hours → consider escalation to high-dose amoxicillin-clavulanate. 2, 4

• Orbital complications (periorbital swelling, proptosis, impaired eye movements) → obtain immediate contrast-enhanced CT and specialist consultation. 1, 2, 4

• Intracranial complications (altered mental status, severe headache, focal neurologic deficits, seizures) → emergent CT and neurosurgical evaluation. 2, 4

Alternative Antibiotics for Penicillin Allergy

If the child has a documented penicillin allergy, use one of these alternatives: 6, 5

• Cefdinir 14 mg/kg once daily (or 7 mg/kg twice daily) for 10 days 7, 5
• Cefpodoxime or cefuroxime 6, 5
• Second- and third-generation cephalosporins carry minimal cross-reactivity risk even in penicillin-allergic patients. 6

Parenteral Option for Non-Adherence or Vomiting

• If the child cannot tolerate oral medication or adherence is unlikely, give ceftriaxone 50 mg/kg (maximum 2 grams) as a single intramuscular or intravenous dose. 6

• If clinical improvement occurs within 24 hours, switch to oral high-dose amoxicillin-clavulanate to complete the 10–14 day course. 6

• If the child remains significantly febrile or symptomatic at 24 hours, additional parenteral ceftriaxone doses may be required before transitioning to oral therapy. 6

Microbiologic Rationale

The three major pathogens in pediatric acute bacterial sinusitis are: 1, 2

• Streptococcus pneumoniae (~30%) 1, 2
• Nontypeable Haemophilus influenzae (~20–30%) 1, 5
• Moraxella catarrhalis (~10–20%) 1, 5

Approximately 10–15% of S. pneumoniae isolates are penicillin-nonsusceptible, and 10–42% of H. influenzae and nearly 100% of M. catarrhalis produce β-lactamase, justifying escalation to amoxicillin-clavulanate in treatment failures. 6

Common Pitfalls to Avoid

• Do not delay antibiotic therapy once the diagnosis is confirmed; although the AAP permits a 3-day observation period for persistent cases, this option is only appropriate at exactly 10 days of symptoms, not for severe or worsening presentations. 1, 2

• Do not obtain sinus imaging in uncomplicated cases—imaging is reserved exclusively for suspected orbital or intracranial complications. 1, 2

• Do not prescribe trimethoprim-sulfamethoxazole or azithromycin due to high resistance rates among common pathogens. 6

• Do not use antihistamines or decongestants as primary treatment, as randomized trials show no incremental benefit when added to antibiotics. 8

• Do not start with amoxicillin-clavulanate unless risk factors for resistant organisms are present; standard amoxicillin remains first-line for uncomplicated disease. 2, 8