What is the treatment for sinusitis?

Treatment of Sinusitis

Amoxicillin is the first-line antibiotic for acute bacterial sinusitis, dosed at 500 mg twice daily (or 875 mg twice daily for more severe infections) for 10-14 days, with treatment continuing until symptom-free for 7 days. 1, 2

Distinguishing Bacterial from Viral Sinusitis

Before initiating antibiotics, confirm acute bacterial sinusitis using one of three clinical patterns: 1, 2

• Persistent symptoms ≥10 days without improvement (nasal congestion, purulent rhinorrhea, postnasal drainage, facial/dental pain, headache, cough)
• Severe symptoms for ≥3 consecutive days (high fever >39°C with purulent nasal discharge and facial pain)
• "Double sickening" - worsening symptoms after initial improvement from a viral upper respiratory infection

Most acute rhinosinusitis cases are viral and resolve within 7 days without antibiotics. 2

First-Line Antibiotic Treatment

Standard Therapy (Uncomplicated Cases)

• Amoxicillin 500 mg twice daily for mild disease without recent antibiotic exposure 2
• Amoxicillin 875 mg twice daily for moderate disease 2
• Duration: 10-14 days or until symptom-free for 7 days 1, 2

High-Risk or Resistant Organisms

• Amoxicillin-clavulanate 875 mg/125 mg twice daily for patients with recent antibiotic exposure, daycare attendance, age <2 years, or regions with high prevalence of resistant S. pneumoniae 2
• The clavulanate component provides coverage against β-lactamase-producing H. influenzae and M. catarrhalis 2

Penicillin-Allergic Patients

Second- or third-generation cephalosporins are preferred over fluoroquinolones due to negligible cross-reactivity risk with penicillin allergy: 2

• Cefuroxime-axetil (second-generation cephalosporin) 3, 2
• Cefpodoxime-proxetil (third-generation, superior activity against H. influenzae) 3, 2
• Cefdinir (third-generation, excellent coverage) 3, 2

Reserve fluoroquinolones (levofloxacin 500-750 mg once daily or moxifloxacin) for documented severe beta-lactam allergy or treatment failures to prevent resistance development. 2

Avoid azithromycin and macrolides - they have 20-25% resistance rates and should not be used as first-line therapy. 2

Treatment Failure Protocol

If no improvement after 3-5 days, reassess diagnosis and switch antibiotics: 3, 2

• Switch to amoxicillin-clavulanate (high-dose: 875 mg/125 mg twice daily or 4 g/250 mg per day) 3, 2
• Alternative: Respiratory fluoroquinolones (levofloxacin or moxifloxacin) provide 90-92% predicted clinical efficacy 2
• Continue treatment for another 10-14 days 3

For sinusitis failing to improve after 21-28 days of initial treatment, consider broader-spectrum agents with or without anaerobic coverage (clindamycin or metronidazole). 3

Adjunctive Therapies

Intranasal Corticosteroids (Strongly Recommended)

• Fluticasone propionate 200 mcg daily (two 50-mcg sprays per nostril once daily) as adjunct to antibiotics for both acute and chronic sinusitis 3, 1, 4
• Decreases nasal mucosal eosinophils and basophils, reduces inflammation and congestion 3, 4
• Maximum benefit may take several days; can be used regularly or as-needed in adults 4

Systemic Corticosteroids (Selective Use)

• Short-term oral corticosteroids (typically 5 days) for patients with marked mucosal edema, nasal polyps, or failure to respond to initial antibiotic treatment 3, 1, 2
• Dexamethasone 4 mg may be used as short-term adjunctive therapy for acute hyperalgic sinusitis (severe pain) when combined with appropriate antibiotics 2

Supportive Measures

• Daily high-volume saline irrigation for chronic sinusitis 1
• Adequate hydration, analgesics (acetaminophen, NSAIDs), warm facial packs 2
• Decongestants (systemic or topical) to promote drainage 3, 2
• Sleep with head elevated 2

Chronic Sinusitis (Symptoms ≥8 Weeks)

Intranasal corticosteroids are first-line therapy for chronic sinusitis, not antibiotics. 1

• Daily high-volume saline irrigation 1
• Longer duration antibiotic therapy may be required for chronic infectious sinusitis 1
• Consider short course of systemic corticosteroids or doxycycline for patients with nasal polyps 1
• Evaluate for underlying allergic rhinitis, immunodeficiency, and anatomic abnormalities 3, 1

Consider non-infectious chronic hyperplastic eosinophilic rhinosinusitis - this does not respond to antibiotics and may require systemic corticosteroids. 3

Recurrent Sinusitis (≥3 Episodes Per Year)

Patients require comprehensive evaluation: 3, 2

• Assess for allergic rhinitis - measure IgE sensitization to inhalant allergens 3
• Evaluate for immunodeficiency - measure quantitative serum IgG, IgA, IgM levels and specific antibody responses 3
• Identify anatomic abnormalities - consider sinus CT scan 3
• Referral to allergist-immunologist for treatment of underlying allergic factors, unusual pathogens, or immunodeficiency 3, 2
• Referral to otolaryngologist for structural abnormalities or medically resistant disease 3

Pediatric Dosing

• Amoxicillin 45 mg/kg/day in 2 divided doses for standard therapy 2
• High-dose amoxicillin 80-90 mg/kg/day in 2 divided doses for areas with high prevalence of resistant S. pneumoniae or risk factors 2
• Amoxicillin-clavulanate 80-90 mg/kg/day of amoxicillin component with 6.4 mg/kg/day clavulanate in 2 divided doses for children with risk factors 2
• Reassess at 72 hours if no improvement 2

Critical Pitfalls to Avoid

• Do not use antibiotics for viral rhinosinusitis - most cases resolve within 7 days without treatment 2
• Ensure adequate treatment duration (minimum 10-14 days) to prevent relapse; instruct patients to complete the full course even after symptoms improve 1, 2
• Avoid fluoroquinolone overuse - reserve for treatment failures, complicated sinusitis, or severe beta-lactam allergy to prevent resistance 2
• Do not use azithromycin or macrolides as first-line therapy due to high resistance rates 2
• Address underlying risk factors (allergies, anatomical abnormalities) to prevent recurrent disease 3, 1
• Dexamethasone should never be used as monotherapy for bacterial sinusitis - antibiotics are necessary to treat the underlying infection 2