What is the treatment for sinusitis?

Treatment of Sinusitis

Amoxicillin at 1.5-4 g/day for 10-14 days is the recommended first-line antibiotic therapy for acute bacterial sinusitis, with treatment continued until 7 days after symptom resolution. 1, 2

Initial Management Approach

Distinguishing Bacterial from Viral Sinusitis

Before initiating antibiotics, confirm bacterial sinusitis is likely by identifying one of these patterns: 3

• Symptoms persisting beyond 10 days without improvement
• Worsening symptoms after initial improvement within 10 days ("double worsening")
• Severe symptoms in the first 3-4 days with high fever (≥39°C) and purulent discharge for 3+ consecutive days

Most acute upper respiratory infections are viral and do not require antibiotics; persistence of symptoms for ≥7 days makes bacterial sinusitis more likely. 4

First-Line Antibiotic Therapy

Amoxicillin remains the initial antibiotic of choice: 1, 2

• Dose: 1.5-4 g/day divided doses
• Duration: 10-14 days total, or continue until 7 days after symptom resolution 1

Essential Adjunctive Therapies

These should be started alongside antibiotics: 1, 2

• Nasal corticosteroids reduce mucosal inflammation and are beneficial in both acute and chronic sinusitis
• Decongestants (topical or systemic) may reduce tissue edema and facilitate drainage
• Comfort measures: adequate hydration, analgesics, warm facial compresses, steam showers, and sleeping with head elevated 2

Important caveat: Antihistamines have no role in treating sinusitis unless the patient has concomitant allergic rhinitis with active symptoms during allergy season. 5, 6

Management of Treatment Failures

Reassessment at 3-5 Days

Evaluate clinical response after 3-5 days of initial therapy. 1, 2

Switch to High-Dose Amoxicillin-Clavulanate

If no improvement after 3-5 days, switch to high-dose amoxicillin-clavulanate: 1, 2

• Adults: 875 mg/125 mg every 12 hours, or for more severe respiratory infections, this is the preferred dose 7
• High-dose pediatric formulation: 90 mg/kg amoxicillin component with 6.4 mg/kg clavulanate, maximum 2g every 12 hours 1
• Duration: 10-14 days 1

Alternative Antibiotics

For penicillin allergy or resistant bacteria, consider: 1, 2

• Cephalosporins (cefuroxime, cefpodoxime, cefdinir)
• Respiratory fluoroquinolones
• Macrolides

Chronic Sinusitis (≥8 Weeks Duration)

Chronic sinusitis requires a fundamentally different approach than acute bacterial sinusitis because it may be noninfectious. 1

Key Distinctions

• Requires both symptoms persisting ≥8 weeks AND abnormal CT or MRI findings 1, 3
• Chronic hyperplastic eosinophilic rhinosinusitis does not respond to antibiotics 1
• Consider systemic corticosteroids for eosinophilic disease 1

Diagnostic Imaging

CT imaging is indicated for: 1

• Chronic sinusitis evaluation
• Treatment failures
• Suspected complications
• Order coronal sinus CT with extra cuts through the ostiomeatal complex 1

When to Refer to Specialists

Allergist-Immunologist Referral

Refer for: 1, 2

• Recurrent sinusitis (≥3 episodes per year)
• Chronic or recurrent sinusitis associated with otitis media, bronchitis, bronchiectasis, or pneumonia
• Suspected immunodeficiency
• Need for evaluation of IgE sensitization to inhalant allergens 1

Otolaryngology Referral

Refer for: 1, 2

• Structural abnormalities or nasal polyps
• Consideration for endoscopic sinus surgery
• Sinusitis refractory to appropriate antibiotic therapy

Red Flags Requiring Immediate Evaluation

Patients with these findings require urgent assessment: 3

• Orbital complications (periorbital edema, vision changes, ophthalmoplegia)
• Neurological complications (altered mental status, severe headache with high fever)
• Signs of intracranial or intraorbital sepsis 8

Common Pitfalls to Avoid

• Do not substitute two 250 mg/125 mg amoxicillin-clavulanate tablets for one 500 mg/125 mg tablet - they contain the same amount of clavulanic acid (125 mg) and are not equivalent 7
• Do not use antihistamines routinely - they have no role unless concurrent allergic rhinitis is symptomatic 5, 6
• Do not order imaging for uncomplicated acute sinusitis - diagnosis is clinical; reserve CT for chronic sinusitis, treatment failures, or suspected complications 1, 4
• Recognize that most acute upper respiratory infections are viral - antibiotics are only appropriate when bacterial sinusitis is likely based on symptom duration and pattern 4