Treatment of Sinusitis
Initial Diagnostic Approach: Distinguish Viral from Bacterial
Most sinusitis (98-99.5%) is viral and resolves spontaneously within 7-10 days without antibiotics. 1, 2 Prescribe antibiotics only when acute bacterial rhinosinusitis (ABRS) is confirmed by one of three patterns: 1, 2
- Persistent symptoms ≥10 days without clinical improvement 1, 2
- Severe symptoms (fever ≥39°C with purulent nasal discharge and facial pain) for ≥3-4 consecutive days 1, 2
- "Double sickening": worsening symptoms after initial improvement from a viral upper respiratory infection 1, 2
Do not obtain imaging (X-ray or CT) for uncomplicated acute sinusitis unless complications or alternative diagnoses are suspected. 1, 2
First-Line Antibiotic Treatment for Uncomplicated Acute Bacterial Sinusitis
Standard Patients
Amoxicillin-clavulanate 875 mg/125 mg twice daily for 5-10 days is the preferred first-line antibiotic for most adults with confirmed ABRS. 1, 2 This provides 90-92% predicted clinical efficacy against the major pathogens (Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis). 2, 3
Plain amoxicillin 500 mg twice daily (mild disease) or 875 mg twice daily (moderate disease) remains acceptable for uncomplicated cases without recent antibiotic exposure. 2
Treatment duration: 5-10 days for adults, or until symptom-free for 7 days (typically 10-14 days total). 2 Shorter 5-7 day courses have comparable efficacy with fewer adverse effects. 2
High-Risk Patients Requiring High-Dose Therapy
Use high-dose amoxicillin-clavulanate (2 g amoxicillin/125 mg clavulanate twice daily) for patients with: 2
- Recent antibiotic use within the past 4-6 weeks 2
- Age >65 years 2
- Moderate-to-severe symptoms 2
- Comorbid conditions or immunocompromised state 2
Pediatric Dosing
- Standard-dose amoxicillin: 45 mg/kg/day divided into 2 doses for uncomplicated disease 2
- High-dose amoxicillin: 80-90 mg/kg/day divided into 2 doses for children <2 years, daycare attendance, or recent antibiotic use 2
- High-dose amoxicillin-clavulanate: 80-90 mg/kg/day of amoxicillin component with 6.4 mg/kg/day clavulanate in 2 divided doses for treatment failures 2
- Treatment duration: Minimum 10-14 days for children 2
Watchful Waiting as an Alternative Initial Strategy
For adults with uncomplicated ABRS, watchful waiting without immediate antibiotics is equally appropriate when reliable follow-up can be assured. 1, 2 Start antibiotics only if no improvement occurs by 7 days or symptoms worsen at any time. 1, 2 The number needed to treat with antibiotics is 10-15 to achieve one additional cure. 2
Penicillin-Allergic Patients
Non-Severe (Non-Type I) Penicillin Allergy
Second- or third-generation cephalosporins are the preferred alternatives, as the risk of cross-reactivity is negligible: 2, 4
- Second-generation: Cefuroxime-axetil 2
- Third-generation: Cefpodoxime-proxetil, cefdinir, or cefprozil 2
- Dosing: Cefdinir 300 mg twice daily or 600 mg once daily for 10 days 2
Severe (Type I) Penicillin Allergy or True Beta-Lactam Allergy
Respiratory fluoroquinolones are the first-line choice when all beta-lactams are contraindicated: 2
- Levofloxacin 500 mg once daily for 10-14 days 2
- Moxifloxacin 400 mg once daily for 10 days 2
- These provide 90-92% predicted clinical efficacy 2
Doxycycline 100 mg once daily for 10 days is an acceptable but suboptimal alternative (77-81% efficacy) with limited activity against H. influenzae. 2
Do NOT use: 2
- Azithromycin or other macrolides (20-25% resistance rates) 2
- Trimethoprim-sulfamethoxazole (50% resistance for S. pneumoniae) 2
- First-generation cephalosporins like cephalexin (inadequate H. influenzae coverage) 2
Treatment Failure Protocol: When and How to Switch Antibiotics
Reassessment Timepoints
Reassess at 3-5 days: If no improvement or worsening, switch antibiotics immediately. 2 Only 30-41% of patients improve by days 3-5, so lack of complete resolution does not necessarily indicate failure. 2
Reassess at 7 days: If symptoms persist, reconfirm the diagnosis and exclude complications. 2 By 7 days, 73-85% of patients show improvement even with placebo. 2
Second-Line Antibiotic Options
If initial amoxicillin or amoxicillin-clavulanate fails: 1, 2
- High-dose amoxicillin-clavulanate (if not already used): 2 g/125 mg twice daily 2
- Respiratory fluoroquinolones: Levofloxacin 500 mg once daily or moxifloxacin 400 mg once daily for 10 days 2
- Third-generation cephalosporins: Cefpodoxime-proxetil or cefdinir (superior H. influenzae activity) 2
- Ceftriaxone: 1-2 g IM/IV once daily for 5 days (for patients unable to tolerate oral medications or moderate-to-severe disease) 2
For sinusitis failing to improve after 21-28 days: Consider broader-spectrum agents with or without anaerobic coverage (clindamycin or metronidazole). 1
Essential Adjunctive Therapies (For All Patients)
These improve outcomes regardless of antibiotic choice: 2
- Intranasal corticosteroids (mometasone, fluticasone, or budesonide twice daily): Reduce mucosal inflammation and improve symptom resolution 2
- Saline nasal irrigation: Provides symptomatic relief and removes mucus 2
- Analgesics (acetaminophen or ibuprofen): Relieve pain and fever 2
- Adequate hydration 2
- Decongestants (systemic or topical): Use cautiously for symptomatic relief 2
Short-term oral corticosteroids (typically 5 days) may be considered for patients with marked mucosal edema or who fail to respond to initial treatment. 1, 2
Chronic Rhinosinusitis (Symptoms ≥8-12 Weeks)
Chronic sinusitis requires fundamentally different management than acute disease. 1, 5
First-Line Treatment
- Daily high-volume saline irrigation combined with intranasal corticosteroid sprays 5
- Smoking cessation if applicable 5
Role of Antibiotics
Antibiotics should be reserved for chronic infectious sinusitis with evidence of active bacterial infection. 5 Consider longer duration therapy (potentially 3 months) with attention to anaerobic pathogens. 5
Chronic hyperplastic eosinophilic rhinosinusitis does not respond to antibiotics and requires systemic corticosteroids. 1
Evaluation for Underlying Causes
- Allergic rhinitis: Consider antihistamines, allergy testing, and immunotherapy 1, 5
- Immunodeficiency: Measure quantitative serum IgG, IgA, IgM levels and specific antibody responses 1
- Anatomic abnormalities: Obtain coronal sinus CT with extra cuts through the ostiomeatal complex 1
- Gastroesophageal reflux disease (GERD): Medical treatment of GERD improves sinusitis symptoms 5
When to Refer to Specialist
Refer to an otolaryngologist or allergist-immunologist when: 1, 5
- First-line medical therapy fails after 8-12 weeks 5
- Sinusitis is refractory to two courses of appropriate antibiotics 2
- Quality of life is significantly affected 5
- Sinusitis is recurrent (≥3 episodes per year) 5
- Associated with unusual opportunistic infections 1
- Suspected complications (orbital cellulitis, meningitis, brain abscess) 2
Surgical Considerations
Functional endoscopic sinus surgery may be considered for medically resistant sinusitis, particularly with localized persistent disease within the ostiomeatal complex. 1, 5 Defer surgery until smoking cessation is achieved. 5
Recurrent Acute Rhinosinusitis (≥3 Episodes Per Year)
Patients with recurrent sinusitis require comprehensive evaluation for underlying causes: 1, 4
- Allergic rhinitis: Evaluate for IgE sensitization to inhalant allergens 1, 4
- Immunodeficiency: Measure quantitative immunoglobulins and specific antibody responses 1, 4
- Anatomic abnormalities: Obtain CT scan of paranasal sinuses 1, 4
Preventive Measures
- Daily intranasal corticosteroids to reduce mucosal inflammation 4
- Daily high-volume saline nasal irrigation to improve mucociliary function 4
- Smoking cessation 4
- Good hand hygiene to minimize viral pathogen exposure 4
Acute Exacerbations
Treat with high-dose amoxicillin-clavulanate (1.5-4 g/day) for 10-14 days. 4
Special Populations and Considerations
Immunocompromised Patients
Referral to an allergist-immunologist is particularly indicated in patients with chronic or recurrent sinusitis associated with: 1
- Otitis media, bronchitis, bronchiectasis, or pneumonia 1
- Prior surgical procedures with continued sinusitis 1
Consider unusual pathogens including Pseudomonas aeruginosa in immunocompromised patients, those with nasal tubes/catheters, or intubated patients. 3
Patients with Asthma
Medical or surgical management of sinusitis results in objective and subjective improvement of asthma. 5, 6
Patients with Nasal Polyps
Nasal polyps in adults may be associated with nonsteroidal anti-inflammatory drug sensitivity and asthma. 1 In children, nasal polyps should prompt evaluation for cystic fibrosis. 1
Critical Pitfalls to Avoid
- Do not prescribe antibiotics for symptoms <10 days unless severe features are present (fever ≥39°C with purulent discharge for ≥3 consecutive days) 1, 2
- Do not use azithromycin or other macrolides as first-line therapy due to 20-25% resistance rates 2
- Do not use fluoroquinolones as routine first-line therapy in patients without documented beta-lactam allergies—reserve them for treatment failures or severe allergies to prevent resistance development 2
- Do not use first-generation cephalosporins (cephalexin, cefadroxil) due to inadequate H. influenzae coverage 2
- Do not use trimethoprim-sulfamethoxazole due to 50% resistance for S. pneumoniae 2
- Do not give systemic corticosteroids without antibiotics when bacterial sinusitis is suspected, as this may suppress the immune response and allow bacterial proliferation 2
- Ensure adequate treatment duration: Minimum 5 days for adults and 10 days for children to prevent relapse 2
- Reassess at 3-5 days (adults) or 72 hours (children) if no improvement to avoid treatment failure 2
- Waiting beyond 7 days to change therapy in non-responders delays effective treatment and may allow complications to develop 2