Treatment of Acute Sinusitis
First-Line Approach: Symptomatic Management for Most Patients
Most cases of acute sinusitis are viral and resolve spontaneously within 7-10 days without antibiotics—symptomatic treatment with analgesics, nasal saline irrigation, and decongestants should be the initial approach, with antibiotics reserved only for patients meeting specific bacterial criteria. 1
When to Start Antibiotics: Three Specific Patterns
Antibiotics should only be initiated when acute bacterial sinusitis is confirmed by one of these three patterns 1, 2:
- Persistent symptoms ≥10 days without clinical improvement (nasal discharge, congestion, facial pain/pressure) 1, 2
- Severe symptoms for ≥3 consecutive days: fever ≥39°C (102.2°F) with purulent nasal discharge and facial pain 1, 2
- "Double sickening": worsening symptoms after initial improvement from a viral upper respiratory infection 1, 2
Critical pitfall: 98-99.5% of acute rhinosinusitis is viral, yet antibiotics are prescribed in 81-92% of cases—this massive overtreatment drives antimicrobial resistance without clinical benefit 1, 3
Symptomatic Treatment (Appropriate for ALL Patients)
Analgesics
Nasal Saline Irrigation
- Promotes mucus clearance and temporarily reduces tissue edema 1
- Can be used with hypertonic or normal saline 1
- No serious adverse effects and beneficial in both acute and chronic sinusitis 1
Decongestants
- Topical decongestants (oxymetazoline, phenylephrine): Use for ≤3 days maximum to avoid rebound congestion 1, 4
- Oral decongestants (pseudoephedrine): Provides symptomatic relief, though evidence is limited 1
Intranasal Corticosteroids
- Mometasone, fluticasone, or budesonide twice daily provides modest but clinically important benefits 1
- Number needed to treat = 14 for symptom improvement 1
- Particularly beneficial when marked mucosal edema is present 1, 3
What NOT to Use
- Antihistamines should be avoided unless the patient has concurrent allergic rhinitis, as they may thicken secretions 1, 4
- Guaifenesin has theoretical benefits but insufficient evidence 1
Antibiotic Therapy: When Bacterial Sinusitis is Confirmed
First-Line Antibiotic: Amoxicillin
Amoxicillin is the preferred first-line antibiotic for uncomplicated acute bacterial sinusitis 1, 3:
- Standard dose: 500 mg twice daily for mild disease 1, 3
- High dose: 875 mg twice daily for moderate disease or areas with high prevalence of resistant S. pneumoniae 1, 3
- Duration: 10-14 days or until symptom-free for 7 days 1, 3
Rationale: Amoxicillin is generally effective, inexpensive, and well-tolerated, with excellent coverage against Streptococcus pneumoniae, the most common bacterial pathogen 1
First-Line Alternative: High-Dose Amoxicillin-Clavulanate
For patients at risk of resistant organisms, high-dose amoxicillin-clavulanate is recommended 1, 3:
- Dose: 875 mg/125 mg twice daily (adults) or 90 mg/kg/day of amoxicillin component with 6.4 mg/kg/day clavulanate in 2 divided doses (children) 1, 3
- Duration: 5-10 days (shorter courses have comparable efficacy with fewer side effects) 3
Risk factors for resistant organisms 1, 3:
- Age <2 years or >65 years
- Daycare attendance
- Recent antibiotic use (within past 4-6 weeks)
- Hospitalization within past 5 days
- Immunocompromised status
The clavulanate component provides coverage against β-lactamase-producing H. influenzae and M. catarrhalis, which have become increasingly prevalent 3
Penicillin-Allergic Patients
Non-Severe Penicillin Allergy (Rash, Mild Reactions)
Second- or third-generation cephalosporins are safe and effective for patients with non-anaphylactic penicillin allergy 1, 3:
- Cefuroxime-axetil (second-generation): Standard alternative 1, 3
- Cefpodoxime-proxetil (third-generation): Superior activity against H. influenzae 1, 3
- Cefdinir (third-generation): Excellent coverage 1, 3
Evidence: Recent data show the risk of serious allergic reactions to second- and third-generation cephalosporins in penicillin-allergic patients is negligible 3
Severe Penicillin Allergy (Anaphylaxis, Type I Hypersensitivity)
Respiratory fluoroquinolones should be reserved for patients with documented severe beta-lactam allergy 1, 3:
- Levofloxacin: 500 mg once daily for 10-14 days 1, 3, 5
- Moxifloxacin: 400 mg once daily for 10 days 1, 3
Critical caveat: Fluoroquinolones provide 90-92% predicted clinical efficacy but should be reserved to prevent resistance development 1, 3
Alternative for Mild Disease with Penicillin Allergy
What NOT to Use in Penicillin-Allergic Patients
Azithromycin and other macrolides should NOT be used as first-line therapy due to 20-25% resistance rates 3, 6
Second-Line Treatment: When First-Line Antibiotics Fail
Reassessment Timeline
Reassess patients at 3-5 days (adults) or 72 hours (pediatrics) 1, 3:
- If no improvement: Switch to second-line antibiotic or re-evaluate diagnosis 1, 3
- If worsening symptoms: Consider complications or alternative diagnosis 1, 3
Second-Line Antibiotic Options
If amoxicillin fails, switch to high-dose amoxicillin-clavulanate 1, 3:
- Dose: 4 g amoxicillin/250 mg clavulanate per day (adults) or 90 mg/kg/day amoxicillin component (children) 3
- Duration: 10-14 days 3
If amoxicillin-clavulanate fails or patient has severe penicillin allergy, use respiratory fluoroquinolones 1, 3:
- Levofloxacin: 500-750 mg once daily for 10-14 days 1, 3, 5
- Moxifloxacin: 400 mg once daily for 10 days 1, 3
Rationale: Fluoroquinolones provide excellent coverage against multi-drug resistant S. pneumoniae (MDRSP) and β-lactamase-producing H. influenzae 1, 3
Alternative Second-Line Options
Third-generation cephalosporins (if not already tried) 1, 3:
- Cefpodoxime-proxetil or cefdinir: Superior activity against H. influenzae compared to second-generation agents 3
Ceftriaxone (for patients unable to tolerate oral medications) 3:
- Dose: 1-2 g IM or IV once daily for 5 days (adults); 50 mg/kg once daily for 5 days (children) 3
- Advantages: Once-daily dosing, ensures adequate drug levels regardless of GI absorption 3
- Predicted efficacy: 90-92% 3
Special Situations
Frontal, Ethmoidal, or Sphenoidal Sinusitis
Fluoroquinolones (levofloxacin or moxifloxacin) should be considered for sinusitis involving frontal, ethmoidal, or sphenoidal sinuses due to potential for serious complications 1, 3
Pediatric Dosing
Amoxicillin 3:
- Standard dose: 45 mg/kg/day in 2 divided doses for uncomplicated disease 3
- High dose: 80-90 mg/kg/day in 2 divided doses for high-risk children or areas with high prevalence of resistant S. pneumoniae 3
Amoxicillin-clavulanate 3:
- Dose: 80-90 mg/kg/day of amoxicillin component with 6.4 mg/kg/day clavulanate in 2 divided doses 3
Ceftriaxone (for children unable to tolerate oral medication) 3:
- Dose: 50 mg/kg IM as a single dose 3
Watchful Waiting Option
For adults with uncomplicated acute bacterial sinusitis, watchful waiting without immediate antibiotics is appropriate when follow-up can be assured 3:
- Start antibiotics if no improvement by 7 days or worsening at any time 3
- This approach reduces unnecessary antibiotic use while maintaining safety 3
Adjunctive Therapies for Severe or Refractory Cases
Oral Corticosteroids
Short-term oral corticosteroids may be considered for patients who fail to respond to initial treatment or have marked mucosal edema 1, 3:
- Typical duration: 5 days 3
- Must be combined with appropriate antibiotic therapy—never give systemic corticosteroids without antibiotics when bacterial sinusitis is suspected 3
Rationale: Corticosteroids reduce inflammation but have no antibacterial activity; using them alone may suppress immune response and allow bacterial proliferation 3
When to Refer to a Specialist
Refer to otolaryngology if 1, 2:
- Symptoms refractory to two courses of appropriate antibiotics 1
- Recurrent sinusitis (≥3 episodes per year) 1
- Suspected complications: orbital cellulitis, meningitis, intracranial extension 1, 2
- Need for sinus aspiration/culture in immunocompromised patients 1
Critical Pitfalls to Avoid
Overdiagnosis of bacterial sinusitis: Wait at least 10 days before considering antibiotics unless severe symptoms are present 1, 3
Using mucus color alone to determine antibiotic need: Color reflects neutrophils, not bacteria 1
Prescribing azithromycin: Resistance rates exceed 20-25% for both S. pneumoniae and H. influenzae 3
Using first-generation cephalosporins (cephalexin): Inadequate coverage against H. influenzae (nearly 50% are β-lactamase producing) 3
Prolonged use of topical decongestants: Leads to rebound congestion after >3 days 1, 4
Using antihistamines in non-allergic patients: May thicken secretions and worsen symptoms 1, 4
Inadequate treatment duration: Minimum 5 days, typically 7-10 days to prevent relapse 1, 3
Failure to recognize complications: Orbital cellulitis, intracranial extension require urgent intervention 1, 2