How should acute sinusitis be managed, when is bacterial sinusitis suspected, and what are the recommended pharmacologic treatments for viral, bacterial, and chronic sinusitis?

Management of Acute Sinusitis

Amoxicillin for 10-14 days is the first-line antibiotic for acute bacterial sinusitis, but antibiotics should only be started when symptoms persist ≥10 days without improvement, worsen after initial improvement ("double worsening"), or present with severe features (fever ≥102.2°F with purulent discharge for ≥3 consecutive days). 1, 2

Distinguishing Viral from Bacterial Sinusitis

Most acute rhinosinusitis (98-99.5%) is viral and resolves spontaneously within 7-10 days without antibiotics. 3, 2 The critical decision point is recognizing when bacterial infection is likely:

Suspect Bacterial Sinusitis When:

• Persistent symptoms: Nasal discharge or daytime cough lasting >10 days without improvement 1, 2
• Worsening symptoms: Initial improvement followed by worsening of symptoms or new fever/discharge within 10 days ("double worsening") 1, 4
• Severe onset: Fever ≥102.2°F (39°C) with purulent nasal discharge for ≥3 consecutive days 1, 2

Common pitfall: Do not rely on purulent nasal discharge color alone to diagnose bacterial infection—yellow or green mucus reflects neutrophils, not bacteria, and occurs commonly in viral infections. 3

Management of Viral Rhinosinusitis (Symptoms <10 Days)

For patients with symptoms <10 days and no severe features, provide symptomatic treatment only: 2, 4

• Analgesics: Acetaminophen or ibuprofen for facial pain, pressure, and fever 3, 2
• Nasal saline irrigation: High-volume irrigation helps thin secretions and improve drainage 3, 2
• Intranasal corticosteroids: Mometasone, fluticasone, or budesonide twice daily reduces mucosal inflammation 3, 2
• Adequate hydration and warm facial packs for comfort 3, 2
• Topical decongestants: May provide short-term relief but limit to 3-5 days maximum to avoid rhinitis medicamentosa 3

Do not prescribe antibiotics for viral rhinosinusitis—this contributes to antibiotic resistance without clinical benefit. 3, 2

Antibiotic Treatment for Acute Bacterial Sinusitis

First-Line Therapy:

Amoxicillin is the drug of choice based on efficacy, cost, and tolerability: 1, 2, 4

• Standard dose: 500 mg three times daily or 875 mg twice daily for 10-14 days 1, 2
• High-dose: Consider 2g twice daily in areas with high pneumococcal resistance or recent antibiotic exposure 1
• Alternative duration: Treat for 7 days after symptoms resolve (minimum 10 days total) 1

Second-Line Therapy (Treatment Failure or High Resistance Areas):

If no improvement after 3-5 days or in regions with high resistance rates: 1, 2

• Amoxicillin-clavulanate: 875 mg/125 mg twice daily or 2g/125mg twice daily for severe disease 1, 2
• Provides coverage against β-lactamase-producing H. influenzae and M. catarrhalis 1

Penicillin Allergy Options:

For non-anaphylactic penicillin allergy: 1

• Cefdinir, cefuroxime, or cefpodoxime for 10 days 1
• Cross-reactivity risk with second/third-generation cephalosporins is negligible for non-Type I reactions 5

For severe penicillin allergy (anaphylaxis): 5

• Levofloxacin 500-750 mg once daily for 10-14 days 5
• Moxifloxacin 400 mg once daily for 10-14 days 5

Avoid azithromycin and trimethoprim-sulfamethoxazole—resistance rates for S. pneumoniae and H. influenzae exceed 20-50%, making them unreliable. 1, 5

Observation Without Antibiotics:

For selected patients with mild symptoms (mild pain, temperature <101°F) and reliable follow-up, observation for 3 days is reasonable before starting antibiotics. 1, 4 This approach reduces unnecessary antibiotic use while maintaining safety.

Adjunctive Therapies for Acute Bacterial Sinusitis

Intranasal corticosteroids are strongly recommended as adjunctive therapy alongside antibiotics: 1, 3, 2

• Mometasone, fluticasone, or budesonide twice daily 3, 2
• Reduces mucosal inflammation, improves drainage, and accelerates symptom resolution 1, 3
• Particularly effective in patients with allergic rhinitis or marked mucosal edema 3

Additional supportive measures: 3, 2

• Nasal saline irrigation for mucus clearance 3, 2
• Analgesics (acetaminophen or NSAIDs) for pain management 3, 2
• Adequate hydration and head elevation during sleep 3

Evidence does not support routine use of oral antihistamines, decongestants, or mucolytics for acute bacterial sinusitis, though they may provide symptomatic relief in selected cases. 1

Reassessment and Treatment Failure

Reassess at 72 hours: If symptoms worsen or fail to improve after 3 days of antibiotics, consider: 1, 2

• Switching to high-dose amoxicillin-clavulanate if initially on amoxicillin alone 1, 2
• Switching to a respiratory fluoroquinolone (levofloxacin or moxifloxacin) 5
• Re-evaluating the diagnosis to exclude complications or alternative diagnoses 1, 2

Face-to-face re-evaluation is desirable when treatment fails, as drug-resistant bacteria or complications may be present. 1

Management of Chronic Sinusitis (Symptoms >12 Weeks)

Chronic rhinosinusitis requires a different approach focused on inflammation rather than infection: 1, 6

First-Line Treatment:

• Intranasal corticosteroids (daily, long-term) are the primary therapy 3, 6
• High-volume saline irrigation is essential adjunctive treatment 3, 6

Additional Considerations:

• Evaluate and treat underlying conditions: Allergic rhinitis, GERD, immunodeficiency, cystic fibrosis, ciliary dyskinesia 1, 3, 6
• Antibiotics have a controversial role—reserve for superimposed acute bacterial infections, not routine use 1, 6
• Systemic corticosteroids (5-day course) may be reasonable for chronic hyperplastic sinusitis or marked mucosal edema, but never give without antibiotics when bacterial infection is suspected 1, 3

When to Refer:

Refer to otolaryngology or allergy/immunology when: 1, 3, 6

• Symptoms persist after maximal medical therapy (typically 8-12 weeks) 6
• Recurrent acute sinusitis (≥3 episodes per year) 3
• Suspected anatomic abnormalities, nasal polyps, or need for endoscopic sinus surgery 1, 6
• Evaluation for immunodeficiency, cystic fibrosis, or other underlying conditions 1, 6

Complications Requiring Urgent Evaluation

Immediately evaluate for complications if any of the following are present: 1

Orbital Complications:

• Periorbital swelling, proptosis, impaired extraocular movements 1
• Requires contrast-enhanced CT and urgent otolaryngology consultation 1

Intracranial Complications:

• Severe headache, photophobia, seizures, focal neurologic findings 1
• Includes meningitis, brain abscess, subdural/epidural empyema, venous thrombosis 1
• Higher morbidity and mortality than orbital complications 1

Do not obtain imaging (plain films, CT, MRI, ultrasound) to differentiate viral from bacterial sinusitis in uncomplicated cases—diagnosis is clinical. 1 Reserve contrast-enhanced CT or MRI for suspected complications only. 1

Key Pitfalls to Avoid

• Do not prescribe antibiotics for symptoms <10 days unless severe features are present 3, 2
• Do not use mucus color alone to determine need for antibiotics 3
• Do not use topical decongestants >3-5 days to prevent rebound rhinitis medicamentosa 3
• Do not use azithromycin or TMP-SMX as first-line therapy due to high resistance rates 1, 5
• Do not give systemic corticosteroids without antibiotics when bacterial infection is suspected 3
• Do not obtain routine imaging for uncomplicated acute sinusitis 1