What is the recommended initial treatment for acute bacterial rhinosinusitis?

Acute Bacterial Rhinosinusitis: Initial Treatment Recommendations

Amoxicillin-clavulanate is the recommended first-line empiric antimicrobial therapy for acute bacterial rhinosinusitis in both adults and children, initiated as soon as the clinical diagnosis is established. 1, 2

Diagnostic Criteria Before Starting Treatment

Before initiating antibiotics, confirm one of three clinical presentations 2, 3:

• Persistent symptoms lasting ≥10 days without improvement (nasal discharge, congestion, facial pain/pressure) 1, 2
• Severe symptoms at onset: high fever (≥39°C/102°F) with purulent nasal discharge and facial pain for 3-4 consecutive days 1, 2
• "Double-sickening": initial improvement followed by worsening of symptoms after 5-6 days 1, 2

First-Line Antibiotic Selection

Standard Dosing (Mild Disease, No Risk Factors)

• Adults: Amoxicillin-clavulanate 875 mg/125 mg twice daily 1, 2
• Children: Amoxicillin-clavulanate 45 mg/kg/day (amoxicillin component) divided twice daily 1
• Alternative for mild cases: Amoxicillin alone 1.5-4 g/day may be considered in adults without recent antibiotic exposure 4, though amoxicillin-clavulanate is preferred 1

High-Dose Regimen (Moderate-Severe Disease or Risk Factors)

Use high-dose amoxicillin-clavulanate when 1, 2:

• Geographic areas with high prevalence (>10%) of penicillin-resistant S. pneumoniae
• Recent antibiotic use within past 4-6 weeks 2
• Daycare attendance (children) 1
• Age <2 years or >65 years 1
• Hospitalization within past 5 days 1
• Moderate to severe symptoms 1

Dosing:

• Adults: 2 g twice daily 1, 2
• Children: 90 mg/kg/day (amoxicillin component) divided twice daily 1

This high-dose formulation achieves superior efficacy against penicillin-resistant S. pneumoniae, with 97.3% success rates even against resistant strains 5.

Penicillin-Allergic Patients

For patients with penicillin allergy 2, 4:

• Doxycycline 100 mg twice daily (adults) 4
• Respiratory fluoroquinolones (levofloxacin 500-750 mg daily or moxifloxacin 400 mg daily) 2, 6, 7
• Cephalosporins (cefdinir, cefpodoxime, cefuroxime) if non-severe allergy 1, 8

Avoid: Trimethoprim-sulfamethoxazole has bacteriologic failure rates of 20-25% and should only be used when no alternatives exist 4, 9.

Treatment Duration

• Adults: 5-7 days for uncomplicated cases 1, 2
• Children: 10-14 days 1

The shorter adult duration is supported by equivalent outcomes in clinical trials while reducing antibiotic exposure 1.

Watchful Waiting vs. Immediate Antibiotics

For mild symptoms lasting <7 days, watchful waiting is appropriate 2, 3:

• Delay antibiotics for up to 7 days while providing symptomatic treatment 3
• Start antibiotics only if symptoms worsen or fail to improve after 7 days 3
• This approach reduces unnecessary antibiotic use, as most cases resolve spontaneously with only 1 in 10-15 patients benefiting from immediate antibiotics 3

Immediate antibiotics are indicated for 2, 3:

• Severe symptoms (high fever with purulent discharge and facial pain) 2
• Immunocompromised patients 2
• Suspected complications (orbital or intracranial involvement) 1

Adjunctive Therapies

Recommended 1, 2:

• Intranasal saline irrigation (physiologic or hypertonic) for symptom relief 1, 2
• Intranasal corticosteroids, especially in patients with allergic rhinitis history 1, 2

Not recommended 1, 2:

• Oral or topical decongestants (strong recommendation against) 1
• Oral antihistamines 1

Reassessment for Treatment Failure

Reassess patients at 72 hours after initiating therapy 1, 4:

• Worsening symptoms or failure to improve indicates treatment failure 1
• Switch to alternative antibiotic with broader coverage (e.g., respiratory fluoroquinolone or high-dose amoxicillin-clavulanate if not already used) 1, 2
• Consider imaging or specialist referral if no improvement after second antibiotic course 2

Critical Pitfalls to Avoid

• Do not routinely cover MRSA during initial empiric therapy—it is not recommended despite being a potential pathogen 1
• Do not use broad-spectrum parenteral antibiotics (like ceftriaxone) for uncomplicated cases, as this promotes resistance and is not cost-effective 4, though one small study suggested ceftriaxone superiority 10, the guideline evidence strongly recommends against this approach 4
• Do not prescribe antibiotics for viral rhinosinusitis (symptoms <10 days with improvement trend), as 40-60% resolve spontaneously 4, 9
• Do not use topical decongestants >3 days to avoid rebound congestion 9