What is the first-line treatment for acute bacterial sinusitis in children?

First-Line Treatment for Acute Bacterial Sinusitis in Children

Amoxicillin with or without clavulanate is the first-line antibiotic treatment for acute bacterial sinusitis in children, with the choice between standard-dose amoxicillin versus high-dose amoxicillin-clavulanate determined by specific risk factors. 1

Diagnostic Criteria Before Treatment

Before initiating antibiotics, confirm the diagnosis using one of three clinical presentations 1:

• Persistent illness: Nasal discharge (any quality) or daytime cough lasting ≥10 days without improvement 1
• Severe onset: Fever ≥39°C (102.2°F) with purulent nasal discharge for ≥3 consecutive days 1
• Worsening course: Initial improvement followed by worsening or new onset of nasal discharge, daytime cough, or fever 1

Treatment Algorithm Based on Risk Stratification

Standard-Dose Amoxicillin (45 mg/kg/day divided twice daily)

Use this for children who meet ALL of the following low-risk criteria 2, 3:

• Age >2 years
• No daycare attendance
• No antibiotic exposure in the previous 4-6 weeks
• Community with low prevalence of resistant S. pneumoniae (<10%)

High-Dose Amoxicillin-Clavulanate (90 mg/kg/day of amoxicillin component)

Use this for children with ANY of the following high-risk factors 1, 2, 3:

• Age <2 years
• Daycare attendance
• Recent antibiotic use (within 4-6 weeks)
• High local prevalence of resistant S. pneumoniae
• Severe or worsening clinical presentation

The rationale for high-dose therapy is that 10-15% of S. pneumoniae isolates are nonsusceptible to penicillin, and 10-42% of H. influenzae and nearly 100% of M. catarrhalis produce β-lactamase 4.

Treatment Duration

Treat for 10-14 days total. 1, 2, 4

Penicillin-Allergic Patients

For children with penicillin allergy 1, 4:

• Non-severe allergy (e.g., rash): Cefdinir, cefpodoxime proxetil, or cefuroxime axetil
• Severe Type I hypersensitivity: Note that macrolides (azithromycin, clarithromycin) have limited effectiveness with bacterial failure rates of 20-25% and should be avoided when possible 1

Critical caveat: Azithromycin and trimethoprim-sulfamethoxazole should not be used due to high resistance rates among common pathogens 4. The FDA label indicates azithromycin 10 mg/kg once daily for 3 days for pediatric sinusitis 5, but this contradicts current guideline recommendations due to resistance concerns.

Reassessment at 72 Hours

Mandatory reassessment is required at 72 hours because clinical trial data show that children who fail to improve by day 3 are unlikely to improve without intervention 2. If there is worsening or failure to improve 1, 2:

• Switch to high-dose amoxicillin-clavulanate (if initially on amoxicillin alone)
• Consider ceftriaxone 50 mg/kg IM/IV once daily if oral adherence is unlikely 2, 4
• Reassess the diagnosis to ensure bacterial sinusitis is correct

When to Treat Immediately vs. Observe

• Severe onset or worsening course: Always treat immediately with antibiotics 1, 4
• Persistent illness only: Either treat immediately OR observe for an additional 3 days before initiating antibiotics, using shared decision-making based on symptom severity 1, 4

Red Flags Requiring Immediate Imaging and Specialist Consultation

Do NOT obtain imaging for uncomplicated sinusitis 1, 4. However, obtain contrast-enhanced CT and immediate ENT/neurosurgery consultation if any of the following are present 2, 4:

• Periorbital or orbital swelling with proptosis
• Impaired extraocular muscle function or visual acuity
• Severe headache with photophobia
• Altered mental status or seizures
• Focal neurologic findings

For suspected orbital or intracranial complications, initiate IV vancomycin plus ceftriaxone or cefotaxime immediately 2.

Common Pitfalls to Avoid

• Do not obtain imaging (CT or X-ray) to diagnose uncomplicated bacterial sinusitis—it does not contribute to diagnosis and exposes children to unnecessary radiation 1
• Do not use macrolides or TMP-SMX as first-line agents due to high resistance rates 1, 4
• Do not skip the 72-hour reassessment—only 9% of placebo-treated children who failed at day 3 improved between days 3-10 without intervention 2
• Do not confuse viral URI with bacterial sinusitis—bacterial sinusitis requires specific diagnostic criteria, not just nasal congestion 1

Adjunctive Therapy

Intranasal corticosteroids may provide additional benefit when used alongside antibiotics but should not replace antimicrobial therapy 2, 4.