What is the treatment for a sinus infection?

Treatment for Sinus Infection

For acute bacterial sinusitis, amoxicillin-clavulanate 875 mg/125 mg twice daily for 7-10 days is the preferred first-line antibiotic treatment in adults, taken with meals to reduce gastrointestinal upset. 1, 2, 3

When Antibiotics Are Indicated

Antibiotics should be prescribed when you have:

• Persistent symptoms lasting >10 days without improvement (nasal discharge, congestion, or cough) 1, 4
• Severe symptoms with high fever and purulent nasal discharge for 3-4 consecutive days 4
• Worsening symptoms after initial improvement from a viral upper respiratory infection 4
• Unilateral facial pain that worsens when bending forward, particularly over the cheeks or forehead 1, 2

First-Line Antibiotic Selection

Amoxicillin-clavulanate is preferred over plain amoxicillin because 20-30% of Haemophilus influenzae and Moraxella catarrhalis (common sinus bacteria) now produce beta-lactamase enzymes that destroy plain amoxicillin. 1, 2, 4

Adult dosing:

• Amoxicillin-clavulanate 875 mg/125 mg twice daily for 7-10 days 1, 2
• Plain amoxicillin 500-875 mg twice daily remains acceptable for uncomplicated cases without recent antibiotic exposure 1, 5

Pediatric dosing:

• High-dose amoxicillin 80-90 mg/kg/day in 2 divided doses for areas with resistant bacteria 1
• Amoxicillin-clavulanate 80-90 mg/kg/day (amoxicillin component) with 6.4 mg/kg/day clavulanate for children with risk factors (age <2 years, daycare attendance, recent antibiotic use) 1

Treatment Duration

Treat for 7-10 days, or until symptom-free for 7 days (typically 10-14 days total). 1, 5, 2 Shorter 5-7 day courses with certain cephalosporins show comparable efficacy with fewer side effects, but standard therapy remains 10-14 days. 1, 2

For Penicillin-Allergic Patients

Second- or third-generation cephalosporins are the preferred alternatives, as the risk of cross-reactivity with penicillin allergy is negligible. 1

Options include:

• Cefuroxime-axetil (second-generation) 1, 5
• Cefpodoxime-proxetil (third-generation, superior activity against H. influenzae) 1, 5
• Cefdinir (third-generation) 1, 5

For severe beta-lactam allergy: Levofloxacin 500 mg once daily for 10-14 days, though fluoroquinolones should be reserved for this specific indication to prevent resistance. 1

Critical pitfall: Azithromycin and other macrolides should NOT be used due to 20-25% resistance rates among Streptococcus pneumoniae. 1

When Treatment Fails

If no improvement after 3-5 days, reassess the diagnosis and switch antibiotics. 1, 5

Second-line options:

• High-dose amoxicillin-clavulanate (if not already used) 1, 2
• Respiratory fluoroquinolones: levofloxacin 500-750 mg once daily or moxifloxacin 1
• Third-generation cephalosporins (cefpodoxime, cefdinir) if cefuroxime was used initially 1

Fluoroquinolones provide 90-92% clinical efficacy and excellent coverage against multi-drug resistant S. pneumoniae, making them valuable for treatment failures, but should not be used routinely to prevent resistance. 1

Adjunctive Therapies

Intranasal corticosteroids are recommended as adjuncts to antibiotics in both acute and chronic sinusitis to reduce mucosal inflammation and promote drainage. 1, 5, 2

Short-term oral corticosteroids may be added for patients with:

• Marked mucosal edema 1, 5
• Severe facial pain (acute hyperalgic sinusitis) 1
• Failure to respond to initial antibiotic treatment 1, 5

Supportive measures:

• Adequate hydration 1
• Analgesics for pain relief 1, 5
• Warm facial packs 1, 5
• Sleeping with head elevated 1
• Nasal saline irrigation 6

Nasal decongestants (oxymetazoline) may help reduce congestion but must be limited to ≤3-5 days to avoid rebound congestion (rhinitis medicamentosa). 5, 2

Special Considerations by Sinus Location

For maxillary sinusitis (most common): Standard first-line antibiotics as above 1

For frontal, ethmoidal, or sphenoidal sinusitis: Consider fluoroquinolones (levofloxacin or moxifloxacin) due to potential for serious complications. 1, 5

For sinusitis of dental origin: Antibiotics are definitely indicated. 5

Watchful Waiting Option

For uncomplicated acute bacterial sinusitis in adults, watchful waiting without immediate antibiotics is appropriate when follow-up can be assured, with antibiotics started if no improvement by 7 days or worsening at any time. 1 The number needed to treat with antibiotics is 3-5 for persistent symptoms. 1

Critical Pitfalls to Avoid

• Inadequate treatment duration leads to relapse—complete the full course even after symptoms improve 1, 3
• Overuse of fluoroquinolones as first-line therapy promotes resistance 1, 2
• Extended nasal decongestant use (>3-5 days) causes rebound congestion 5, 2
• Using azithromycin despite high resistance rates 1
• Treating viral upper respiratory infections with antibiotics—most "sinus infections" are viral and resolve without antibiotics 5, 3

When to Refer to a Specialist

Refer when there is:

• Sinusitis refractory to usual antibiotic treatment 1
• Recurrent sinusitis (≥3 episodes per year) 1
• Need to clarify allergic or immunologic basis 1
• Sinusitis associated with unusual opportunistic infections 1