Treatment of Sinusitis
Distinguishing Viral from Bacterial Sinusitis Before Treatment
Most acute rhinosinusitis (98-99.5%) is viral and resolves spontaneously within 7-10 days without antibiotics—antibiotics should only be initiated when acute bacterial sinusitis is confirmed by one of three clinical patterns. 1
The three diagnostic patterns that warrant antibiotic therapy are:
- Persistent symptoms ≥10 days without clinical improvement (nasal congestion, purulent rhinorrhea, postnasal drainage, facial/dental pain, headache, or cough) 1, 2
- Severe symptoms for ≥3 consecutive days: fever ≥39°C with purulent nasal discharge and facial pain 1, 3
- "Double sickening": worsening symptoms after initial improvement from a viral upper respiratory infection 1, 3
Critical pitfall: Do not prescribe antibiotics for symptoms lasting less than 10 days unless severe symptoms are present, as this contributes to antimicrobial resistance without clinical benefit. 1, 2
First-Line Antibiotic Treatment for Acute Bacterial Sinusitis
Adults
Amoxicillin remains the first-line antibiotic for uncomplicated acute bacterial sinusitis, with dosing of 500 mg twice daily for mild disease or 875 mg twice daily for moderate disease. 1, 2
- Treatment duration is 10-14 days or until symptom-free for 7 days 2, 3
- High-dose amoxicillin (875 mg twice daily) is preferred in areas with high prevalence of resistant S. pneumoniae 1, 3
- Amoxicillin-clavulanate (875 mg/125 mg twice daily) provides better coverage against β-lactamase-producing organisms and may be preferred as first-line therapy, particularly with recent antibiotic exposure 3
Pediatric Patients
- Standard dose: amoxicillin 45 mg/kg/day in 2 divided doses 3
- High-dose: amoxicillin 80-90 mg/kg/day in 2 divided doses for children with risk factors (age <2 years, daycare attendance, recent antibiotic use within 4-6 weeks) 3
- Amoxicillin-clavulanate: 80-90 mg/kg/day of amoxicillin component with 6.4 mg/kg/day clavulanate in 2 divided doses for high-risk children 3
Penicillin-Allergic Patients
For patients with documented penicillin allergy, second- or third-generation cephalosporins are the preferred first-line alternatives due to negligible cross-reactivity risk. 3
Non-Severe Penicillin Allergy (Rash, Delayed Reactions)
- Second-generation cephalosporins: cefuroxime-axetil 3
- Third-generation cephalosporins: cefpodoxime-proxetil, cefdinir, or cefprozil 3
- Recent evidence shows the risk of serious allergic reactions to second- and third-generation cephalosporins in penicillin-allergic patients is negligible 3
Severe Beta-Lactam Allergy (Anaphylaxis)
- Respiratory fluoroquinolones: levofloxacin 500 mg once daily or moxifloxacin 400 mg once daily for 10-14 days 3
- Fluoroquinolones should be reserved for severe allergies or treatment failures to prevent resistance development 3
Critical pitfall: Azithromycin and other macrolides should NOT be used as first-line therapy due to resistance rates of 20-25% for both S. pneumoniae and H. influenzae. 3
Treatment Failure Protocol
If no improvement occurs after 3-5 days of initial antibiotic therapy, switch to a different antibiotic or re-evaluate the diagnosis. 2, 3
Second-Line Options After Amoxicillin Failure
- High-dose amoxicillin-clavulanate: 875 mg/125 mg twice daily (adults) or 90 mg/kg/day amoxicillin component with 6.4 mg/kg/day clavulanate in 2 divided doses (children) 3
- This provides coverage against β-lactamase-producing H. influenzae and M. catarrhalis, as well as drug-resistant S. pneumoniae 3
Second-Line Options After Amoxicillin-Clavulanate Failure
- Respiratory fluoroquinolones: levofloxacin 500-750 mg once daily or moxifloxacin 400 mg once daily for 10 days, providing 90-92% predicted clinical efficacy 3
- Third-generation cephalosporins: cefpodoxime-proxetil or cefdinir offer superior activity against H. influenzae 3
- Ceftriaxone: 1-2 g IM or IV once daily for 5 days (adults) or 50 mg/kg once daily (children) for patients unable to tolerate oral medications 3
Critical pitfall: Reassess patients at 72 hours (pediatrics) or 3-5 days (adults) if no improvement to avoid treatment failure. 3
Adjunctive Therapies
Intranasal Corticosteroids (Strongly Recommended)
Intranasal corticosteroids are recommended as adjunctive therapy in both acute and chronic sinusitis to reduce inflammation and improve drainage. 1, 2
- Fluticasone propionate: 200 mcg/day (two 50-mcg sprays in each nostril once daily) or 100 mcg twice daily 4
- Mometasone furoate or budesonide: twice daily 1
- Maximum effect may take several days, though some improvement may occur within 12 hours 4
- Intranasal corticosteroids are unlikely to reach the interior of the paranasal sinuses but effectively relieve nasal congestion, which is a significant component of sinusitis 5
Supportive Measures
- Analgesics: acetaminophen or NSAIDs for pain and fever relief 1, 2
- Saline nasal irrigation: high-volume daily irrigation provides symptomatic relief and removes mucus 1, 2
- Adequate hydration, warm facial packs, and sleeping with head elevated 1, 2
- Decongestants (systemic or topical): provide symptomatic relief, though evidence for efficacy is limited 1
Systemic Corticosteroids (Limited Use)
- Short-term oral corticosteroids may be reasonable for patients who fail to respond to initial treatment, demonstrate nasal polyposis, or have marked mucosal edema 3
- Typical duration is 5 days 3
- Critical pitfall: Never give systemic corticosteroids without antibiotics when bacterial sinusitis is suspected, as this may suppress the immune response and allow bacterial proliferation 3
Chronic Sinusitis Management
Chronic sinusitis is defined as symptoms lasting longer than 8 weeks, and intranasal corticosteroids are first-line therapy. 1, 2
- Daily high-volume saline irrigation is recommended 1, 2
- Longer duration antibiotic therapy (minimum 3 weeks) for chronic infectious sinusitis 1
- For patients with nasal polyps, consider a short course of systemic corticosteroids or doxycycline 2
- Chronic hyperplastic eosinophilic rhinosinusitis does not respond to antibiotics and may require systemic corticosteroids 5
Recurrent Sinusitis (≥3 Episodes Per Year)
Patients with recurrent sinusitis should be evaluated for underlying inflammation, allergy, immunodeficiency, and anatomic abnormalities. 5, 2
- Evaluate for allergic rhinitis with IgE sensitization testing to inhalant allergens 5
- Consider immunodeficiency evaluation: quantitative serum IgG, IgA, IgM levels and specific antibody responses to tetanus toxoid or pneumococcal polysaccharide vaccine 5
- Assess for anatomic abnormalities: nasal septal deviation, middle turbinate deformity, obstructing nasal polyps 5
When to Refer to a Specialist
Refer patients to an otolaryngologist or allergist/immunologist for the following indications: 1, 2
- Sinusitis refractory to usual antibiotic treatment (no improvement after two courses of appropriate antibiotics) 1
- Recurrent sinusitis (≥3 episodes per year) 1, 2
- Suspected complications (orbital or intracranial involvement) 1
- Need to clarify allergic or immunologic basis 1, 2
- Radiographic evidence of ostiomeatal obstruction despite aggressive medical management 5
- Presence of obstructing nasal polyps after appropriate medical treatment including trial of oral corticosteroids 5
Watchful Waiting Option
For adults with uncomplicated acute bacterial sinusitis, watchful waiting without antibiotics is an appropriate initial strategy when follow-up can be assured. 3
- Patients should start antibiotics only if no improvement occurs by 7 days or if symptoms worsen at any time 3
- Approximately 90% of patients with acute rhinosinusitis improve naturally within 7-15 days without antibiotic treatment 3
- The number needed to treat with antibiotics is 3-5 for persistent symptoms 3