What is the recommended treatment for a sinus infection?

Treatment for Acute Bacterial Sinusitis

For uncomplicated maxillary sinusitis in adults, start with amoxicillin-clavulanate 875 mg/125 mg twice daily for 7-10 days, which is the preferred first-line antibiotic based on current resistance patterns. 1

When to Start Antibiotics

Antibiotic therapy is indicated when you observe:

• Persistent symptoms: Nasal discharge or cough lasting >10 days without improvement 1
• Severe symptoms: High fever with purulent nasal discharge for 3-4 consecutive days 2
• Worsening symptoms: Initial improvement followed by deterioration 2
• Unilateral purulent rhinorrhea with pain over the affected sinus that worsens when bending forward 3

Do NOT start antibiotics for diffuse, bilateral nasal symptoms of moderate intensity with serous discharge occurring in an epidemic context—these patients need symptomatic treatment first. 3

First-Line Antibiotic Selection

Standard Cases (Maxillary Sinusitis)

Amoxicillin-clavulanate 875 mg/125 mg twice daily is the preferred first-line choice over plain amoxicillin due to increasing bacterial resistance, particularly beta-lactamase-producing organisms. 1 The duration should be 7-10 days, treating until symptom-free for 7 days. 3, 1

Plain amoxicillin 500 mg twice daily may be acceptable only in uncomplicated cases without recent antibiotic exposure, though this is increasingly less reliable. 1

Penicillin-Allergic Patients

For documented penicillin allergy, use:

• Cefuroxime-axetil (second-generation cephalosporin) 3, 1
• Cefpodoxime-proxetil or cefdinir (third-generation cephalosporins) 3, 1
• Pristinamycin for true beta-lactam allergy 3

The risk of cross-reactivity with second- and third-generation cephalosporins in penicillin-allergic patients is negligible. 1

Critical pitfall: Do NOT use azithromycin or other macrolides as first-line therapy—resistance rates are 20-25% for Streptococcus pneumoniae and Haemophilus influenzae. 1, 4 The FDA label for azithromycin lists 500 mg daily for 3 days for acute bacterial sinusitis, but this should be avoided due to resistance patterns. 4

Treatment Based on Anatomic Location

Frontal, Ethmoidal, or Sphenoidal Sinusitis

These locations carry high risk of serious complications (meningitis, orbital complications). Reserve fluoroquinolones active against pneumococci for these cases:

• Levofloxacin 750 mg daily for 5 days OR 500 mg daily for 10-14 days 1, 5
• Moxifloxacin (alternative fluoroquinolone) 3, 1

Fluoroquinolones should NOT be used as routine first-line therapy for uncomplicated maxillary sinusitis—reserve them to prevent resistance development. 3, 1

Clinical signs requiring fluoroquinolone therapy or hospitalization include: meningeal signs, exophthalmos, palpebral edema, ocular mobility disorders, or severe pain preventing sleep. 3

Second-Line Treatment for Failure

If no improvement occurs after 3-5 days of initial therapy:

• Switch to amoxicillin-clavulanate if started on plain amoxicillin 1
• Switch to a respiratory fluoroquinolone (levofloxacin or moxifloxacin) if already on amoxicillin-clavulanate 1
• Consider imaging and bacteriological testing before switching 3

Adjunctive Therapies

Intranasal corticosteroids should be added to antibiotic therapy in all cases of acute sinusitis to reduce inflammation and promote drainage. 1

Short-term oral corticosteroids (e.g., dexamethasone 4 mg) may be reasonable for:

• Acute hyperalgic sinusitis (severe pain) 1
• Marked mucosal edema 1
• Failure to respond to initial treatment 1

Never use systemic corticosteroids as monotherapy—antibiotics remain essential for bacterial infection. 1

Supportive measures include adequate hydration, analgesics, warm facial packs, and sleeping with head elevated. 1

Watchful Waiting Option

For adults with uncomplicated acute bacterial sinusitis where follow-up is assured, watchful waiting without immediate antibiotics is appropriate. Start antibiotics only if no improvement by 7 days or worsening at any time. 1

Critical Treatment Pitfalls

• Inadequate duration: Complete the full 7-10 day course even after symptoms improve to prevent relapse 1
• Wrong antibiotic choice: Avoid macrolides (azithromycin, clarithromycin) due to high resistance rates 1
• Overuse of fluoroquinolones: Reserve levofloxacin/moxifloxacin for complicated cases or treatment failures 3, 1
• Missing complicated sinusitis: Always assess for warning signs requiring hospitalization and parenteral therapy 3

Pediatric Dosing (Age ≥6 months)

• Amoxicillin: 45 mg/kg/day in 2 divided doses (standard) or 80-90 mg/kg/day (high-dose for resistant S. pneumoniae) 1
• Amoxicillin-clavulanate: 80-90 mg/kg/day of amoxicillin component with 6.4 mg/kg/day clavulanate in 2 divided doses 1
• Duration: 10 mg/kg once daily for 3 days for acute bacterial sinusitis 4