Treatment of Acute Bacterial Sinusitis
Amoxicillin 500 mg twice daily for 10-14 days is the first-line treatment for uncomplicated acute bacterial sinusitis in adults, or 875 mg twice daily for more severe infections. 1
Confirming the Diagnosis Before Treatment
Before initiating antibiotics, ensure the patient meets criteria for acute bacterial sinusitis (not viral rhinosinusitis):
- Persistent symptoms ≥10 days without improvement (nasal discharge, congestion, facial pain/pressure, cough) 1
- Severe symptoms for ≥3 consecutive days (fever >39°C, purulent nasal discharge, severe facial pain) 1
- "Double sickening" - worsening after initial improvement from a viral upper respiratory infection 1
Most acute rhinosinusitis is viral and resolves within 7 days without antibiotics. 1 Overdiagnosis leads to unnecessary antibiotic use and resistance. 2
First-Line Antibiotic Treatment
Standard Therapy (Uncomplicated Cases)
For adults without recent antibiotic exposure or risk factors for resistance:
- Amoxicillin 500 mg twice daily for 10-14 days 1
- For moderate-to-severe disease: Amoxicillin 875 mg twice daily 1
For children:
- Standard dose: Amoxicillin 45 mg/kg/day in 2 divided doses 1
- High-dose (areas with resistant S. pneumoniae or risk factors): 80-90 mg/kg/day in 2 divided doses 1
High-Dose Amoxicillin-Clavulanate (Preferred for Severe Disease)
Amoxicillin-clavulanate 875 mg/125 mg twice daily for 5-10 days is the preferred first-line option for moderate-to-severe acute bacterial sinusitis, recent antibiotic exposure, or areas with high resistance. 1
The clavulanate component provides coverage against β-lactamase-producing H. influenzae and M. catarrhalis, which have become increasingly prevalent. 1 This combination should be taken with meals to reduce gastrointestinal upset. 3
Pediatric dosing: 80-90 mg/kg/day of amoxicillin component with 6.4 mg/kg/day clavulanate in 2 divided doses for children with risk factors (age <2 years, daycare attendance, recent antibiotic use). 1
Treatment Duration
Treat for 10-14 days until symptom-free for 7 days. 1 Shorter 5-7 day courses with certain antibiotics (amoxicillin-clavulanate, some cephalosporins) have comparable efficacy with fewer side effects. 1, 2 However, inadequate treatment duration can lead to relapse. 1
Penicillin-Allergic Patients
For documented penicillin allergy, second- or third-generation cephalosporins are the preferred alternatives, as the risk of cross-reactivity is negligible. 1
Recommended Options:
- Cefuroxime-axetil (second-generation cephalosporin) 1
- Cefpodoxime-proxetil (third-generation, superior activity against H. influenzae) 1
- Cefdinir (third-generation, excellent coverage) 1
For severe beta-lactam allergy: Levofloxacin 500 mg once daily for 10-14 days 1 Reserve fluoroquinolones specifically for situations where beta-lactams are contraindicated due to resistance concerns. 1
Critical pitfall: Azithromycin and other macrolides should NOT be used as first-line therapy due to 20-25% resistance rates. 1
Treatment Failure Protocol
If no improvement after 3-5 days (adults) or 72 hours (children), reassess the diagnosis and switch antibiotics. 1
Second-Line Options:
- High-dose amoxicillin-clavulanate (if not already used): 4 g/250 mg per day 1
- Respiratory fluoroquinolones (levofloxacin 500-750 mg once daily or moxifloxacin): Provide 90-92% predicted clinical efficacy and excellent coverage against multi-drug resistant S. pneumoniae 1
- Third-generation cephalosporins (cefpodoxime, cefdinir): Superior activity against H. influenzae compared to cefuroxime 1
Anatomic Location Considerations
For maxillary sinusitis (most common): Standard first-line antibiotics as above 1
For frontal, ethmoidal, or sphenoidal sinusitis: Consider fluoroquinolones (levofloxacin or moxifloxacin) due to potential for serious complications. 1 These locations require broader coverage and should not be treated with routine first-line therapy. 1
Essential Adjunctive Therapies
Intranasal Corticosteroids (Strongly Recommended)
Intranasal corticosteroids should be added as adjunct to antibiotic therapy in both acute and chronic sinusitis. 1 They decrease inflammation, promote drainage, and may reduce the need for antibiotics. 1, 2
Supportive Measures:
- Saline nasal irrigation: Facilitates mechanical removal of mucus and prevents crusting 2
- Analgesics (acetaminophen, NSAIDs): For pain relief 1
- Adequate hydration, warm facial packs, sleeping with head elevated 1
- Decongestants (systemic or topical): Limited to 5 days to avoid rebound congestion 2
Oral Corticosteroids (Selective Use)
Short-term oral corticosteroids (e.g., dexamethasone 4 mg) may be reasonable for acute hyperalgic sinusitis (severe pain) or marked mucosal edema when patients fail initial treatment. 1 However, corticosteroids should never be used as monotherapy—antibiotics remain necessary for bacterial infection. 1
Watchful Waiting Option
For adults with uncomplicated acute bacterial sinusitis, watchful waiting without immediate antibiotics is appropriate when follow-up can be assured. 1 Start antibiotics if no improvement by 7 days or worsening at any time. 1 The number needed to treat with antibiotics is 3-5 for persistent symptoms. 1
Critical Pitfalls to Avoid
- Do not use azithromycin due to 20-25% resistance rates 1
- Do not use fluoroquinolones routinely as first-line therapy—reserve for treatment failures, complicated sinusitis, or multi-drug resistant organisms to prevent resistance development 1
- Do not use topical decongestants >5 days—leads to rebound congestion (rhinitis medicamentosa) 2
- Do not stop antibiotics early—complete the full 10-14 day course even after symptoms improve to prevent relapse and resistance 1, 3
- Reassess at 3-5 days—failure to reassess leads to prolonged ineffective therapy 1
When to Refer to a Specialist
Refer to an otolaryngologist or allergist/immunologist for: