What are the treatment guidelines for acute sinusitis?

Treatment Guidelines for Acute Sinusitis

Amoxicillin remains the first-line antibiotic for acute bacterial sinusitis in adults and children, with treatment reserved for patients meeting specific clinical criteria rather than all cases of rhinosinusitis. 1

Diagnostic Criteria Before Treatment

The decision to treat with antibiotics depends on three distinct clinical presentations 1:

• Persistent symptoms: Nasal discharge or congestion lasting ≥10 days without improvement 1, 2
• Severe onset: High fever (≥39°C/102°F) with purulent nasal discharge for ≥3-4 consecutive days 1, 2
• Worsening symptoms: Initial improvement followed by clinical deterioration (double-worsening) 1, 2

Most cases of acute rhinosinusitis are viral and do not require antibiotics. Symptoms lasting <7 days are almost always viral and should be managed with supportive care only 3.

Physical examination findings supporting bacterial infection include purulent nasal discharge, unilateral maxillary pain or facial tenderness (especially over teeth), and nasal congestion 1. Imaging is not recommended for routine diagnosis 3, 4.

First-Line Antibiotic Treatment

For uncomplicated acute bacterial sinusitis, prescribe amoxicillin as follows 1, 5:

• Mild disease (no recent antibiotic exposure, low resistance area): Amoxicillin 500 mg twice daily 1
• Moderate disease (recent antibiotics or high S. pneumoniae resistance): Amoxicillin 875 mg twice daily or high-dose 1.5-4 g/day divided 1, 5
• Duration: 10-14 days for most cases 5, 2, or treat for 7 days after symptom resolution with minimum 10 days total 6

The predominant pathogens are Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis 1. Beta-lactamase production occurs in 20% of H. influenzae and 50-70% of M. catarrhalis strains 1.

Penicillin-Allergic Patients

For non-anaphylactic penicillin allergy, use second- or third-generation cephalosporins 1:

• Cefuroxime-axetil, cefpodoxime-proxetil, or cefdinir are acceptable alternatives 1, 2
• Avoid cefixime and ceftibuten as they have poor activity against penicillin-resistant S. pneumoniae 1

For severe penicillin allergy (anaphylaxis), respiratory fluoroquinolones are recommended 6. Trimethoprim-sulfamethoxazole can be used in adults but resistance is more common in children 5.

Azithromycin 500 mg once daily for 3 days is FDA-approved for acute bacterial sinusitis 7, though it is generally considered second-line due to increasing macrolide resistance 2.

Treatment Failure Management

Reassess patients who show no improvement within 72 hours (pediatrics) or 3-5 days (adults) 1, 6:

• Switch to high-dose amoxicillin-clavulanate (90 mg/kg amoxicillin component, maximum 2 g every 12 hours) 1, 5
• Alternative: Respiratory fluoroquinolones (levofloxacin 500 mg daily for 5-10 days or 750 mg daily for 5 days) 8
• Alternative: Second-generation cephalosporins 1

Levofloxacin is FDA-approved for acute bacterial sinusitis at either 500 mg once daily for 10-14 days or 750 mg once daily for 5 days, with equivalent efficacy demonstrated between regimens 8.

Adjunctive Therapies

Intranasal corticosteroids are recommended as adjunctive therapy to reduce mucosal inflammation and improve sinus drainage 1, 5. They decrease edema around sinus ostia 6.

Short-term oral corticosteroids may be reasonable when patients fail initial treatment, have nasal polyposis, or demonstrate marked mucosal edema 1, 5.

Supportive care measures include 5:

• Saline nasal irrigation to improve mucociliary clearance 6, 5
• Nasal decongestants (oxymetazoline) for ≤5 days only to avoid rebound congestion 5
• Analgesics for pain relief 5
• Adequate hydration and rest 5

Watchful Waiting Strategy

For adults with mild, uncomplicated symptoms, watchful waiting without immediate antibiotics is appropriate when reliable follow-up is assured 1. This approach recognizes that many cases resolve spontaneously while avoiding unnecessary antibiotic exposure 3.

Symptomatic treatment with analgesics, decongestants, and saline irrigation is appropriate for patients with nonsevere symptoms (mild pain, temperature <101°F) 4.

Critical Pitfalls to Avoid

• Do not prescribe antibiotics for viral rhinosinusitis (symptoms <7 days without severe features) 3, 4
• Do not use nasal decongestants >5 days due to risk of rhinitis medicamentosa 5
• Complete the full antibiotic course even after symptom improvement to prevent relapse 1
• Do not use fluoroquinolones as first-line for uncomplicated cases 5
• Do not order CT scans routinely; reserve for suspected complications or treatment failures 9, 4

Special Situations Requiring Broader Coverage

Frontal, ethmoidal, or sphenoidal sinusitis requires antibiotic therapy and may need broader coverage 5. Sinusitis of dental origin also definitively requires antibiotics 5. These situations warrant earlier treatment and potentially longer courses (up to 28 days in some guidelines) 10.