What is the treatment for a sinus infection?

Treatment of Acute Bacterial Sinusitis

For acute bacterial sinusitis, start with amoxicillin 500 mg twice daily (mild disease) or 875 mg twice daily (moderate disease) for 10-14 days as first-line therapy, reserving amoxicillin-clavulanate and fluoroquinolones for treatment failures or specific high-risk situations. 1

Confirm the Diagnosis Before Prescribing Antibiotics

Most acute rhinosinusitis (98-99.5%) is viral and resolves spontaneously within 7-10 days without antibiotics. 1 Only prescribe antibiotics when bacterial infection is confirmed by one of three patterns: 1

• Persistent symptoms ≥10 days without clinical improvement 1
• Severe symptoms (fever ≥39°C with purulent nasal discharge and facial pain) for ≥3 consecutive days 1
• "Double sickening" - worsening symptoms after initial improvement from a viral upper respiratory infection 1

Do not use purulent nasal discharge color alone to diagnose bacterial sinusitis, as mucus color reflects neutrophils, not bacteria. 1

First-Line Antibiotic Treatment

Standard First-Line Therapy

• Amoxicillin 500 mg twice daily for mild, uncomplicated maxillary sinusitis 1
• Amoxicillin 875 mg twice daily for moderate disease 1
• Treatment duration: 10-14 days or until symptom-free for 7 days 1

When to Use Amoxicillin-Clavulanate as First-Line

Amoxicillin-clavulanate 875 mg/125 mg twice daily is preferred as first-line therapy in these situations: 1

• Recent antibiotic exposure within past 4-6 weeks 1
• Age <2 years or daycare attendance 1
• Areas with high prevalence of β-lactamase-producing H. influenzae or M. catarrhalis 1
• Moderate-to-severe disease 1

The clavulanate component provides coverage against β-lactamase-producing organisms that have become increasingly prevalent. 1

Treatment for Penicillin-Allergic Patients

Non-Severe Penicillin Allergy (Rash, Delayed Reactions)

Second- or third-generation cephalosporins are safe and effective, as the risk of cross-reactivity is negligible: 1

• Cefuroxime-axetil (second-generation cephalosporin) 2, 1
• Cefpodoxime-proxetil (third-generation, superior activity against H. influenzae) 2, 1
• Cefdinir (third-generation, excellent coverage) 1

Severe Penicillin Allergy (Anaphylaxis, Type I Hypersensitivity)

Reserve respiratory fluoroquinolones for documented severe beta-lactam allergy: 1

• Levofloxacin 500 mg once daily for 10-14 days 1, 3
• Moxifloxacin 400 mg once daily for 10 days 1

Do not use azithromycin or other macrolides due to resistance rates exceeding 20-25% for both S. pneumoniae and H. influenzae. 1

Second-Line Treatment for Treatment Failure

If no improvement occurs after 3-5 days of initial antibiotic therapy, reassess the diagnosis and switch antibiotics: 1

If Initial Therapy Was Amoxicillin

Switch to high-dose amoxicillin-clavulanate: 1

• Adults: 875 mg/125 mg twice daily (or 2000 mg/125 mg twice daily for severe cases) 1
• Pediatrics: 90 mg/kg/day of amoxicillin component with 6.4 mg/kg/day clavulanate in 2 divided doses 1

If Initial Therapy Was Amoxicillin-Clavulanate

Switch to a respiratory fluoroquinolone: 1

• Levofloxacin 500-750 mg once daily for 10-14 days (provides 90-92% predicted clinical efficacy against drug-resistant S. pneumoniae and β-lactamase-producing organisms) 1, 3
• Moxifloxacin 400 mg once daily for 10 days 1

Alternative: Third-generation cephalosporins (cefpodoxime-proxetil or cefdinir) provide superior activity against H. influenzae but have limitations against drug-resistant S. pneumoniae. 1

Treatment Based on Sinusitis Location

Maxillary Sinusitis (Most Common)

• First-line: Amoxicillin or amoxicillin-clavulanate as described above 2, 1
• Symptoms: Unilateral or bilateral infraorbital pain worsening when bending forward, pulsatile, peaking in evening/night 2

Frontal, Ethmoidal, or Sphenoidal Sinusitis

These locations carry high risk of complications and require more aggressive therapy: 2, 1

• Fluoroquinolones (levofloxacin or moxifloxacin) are recommended as first-line therapy due to potential for serious complications 2, 1
• Hospitalization, bacteriological testing, and parenteral antibiotics are indicated if complications are suspected (meningeal syndrome, exophthalmos, palpebral edema, ocular mobility disorders, severe pain preventing sleep) 2

Adjunctive Therapies That Actually Work

Intranasal Corticosteroids (Strongly Recommended)

Intranasal corticosteroids significantly reduce symptoms and should be added to antibiotic therapy: 1, 4

• Mometasone, fluticasone, or budesonide twice daily 1
• Reduces mucosal inflammation, improves symptom resolution, and may decrease antibiotic use 1, 4
• Patients receiving intranasal corticosteroids with antibiotics had significantly greater reduction in headache, facial pain, and congestion compared to antibiotics alone 4

Oral Corticosteroids (Limited Use)

Short-term oral corticosteroids may be reasonable for: 1

• Patients who fail to respond to initial treatment 1
• Marked mucosal edema 1
• Acute hyperalgic sinusitis (severe pain) 1
• Typical regimen: 5 days 1

Never give systemic corticosteroids without antibiotics when bacterial sinusitis is suspected, as this may suppress immune response and allow bacterial proliferation. 1

Supportive Measures

• Analgesics (acetaminophen, NSAIDs) for pain relief 1
• Saline nasal irrigation for symptomatic relief and mechanical removal of mucus 1, 5
• Adequate hydration, warm facial packs, sleeping with head elevated 1
• Decongestants (systemic or topical) may provide symptomatic relief but have limited evidence for efficacy 1

Pediatric Dosing Considerations

• Standard-dose amoxicillin: 45 mg/kg/day in 2 divided doses for uncomplicated disease 1
• High-dose amoxicillin: 80-90 mg/kg/day in 2 divided doses for high-risk children (age <2 years, daycare attendance, recent antibiotic use, areas with high prevalence of resistant S. pneumoniae) 1
• High-dose amoxicillin-clavulanate: 90 mg/kg/day of amoxicillin component with 6.4 mg/kg/day clavulanate in 2 divided doses 1
• Ceftriaxone 50 mg/kg IM or IV once daily for children unable to tolerate oral medication 1

Critical Pitfalls to Avoid

• Do not prescribe antibiotics for symptoms lasting <7 days unless severe symptoms are present, as most cases are viral 1, 6
• Do not use azithromycin due to resistance rates of 20-25% 1
• Do not use trimethoprim-sulfamethoxazole due to high resistance rates 1
• Do not use clindamycin as monotherapy - it lacks activity against H. influenzae and M. catarrhalis 1
• Reserve fluoroquinolones for treatment failures or severe beta-lactam allergy to prevent resistance development 1
• Reassess patients at 3-5 days - if no improvement, switch antibiotics or re-evaluate diagnosis 1
• Complete the full antibiotic course even after symptoms improve to prevent relapse 1

When to Refer to a Specialist

Refer to otolaryngology when: 1, 5

• Symptoms refractory to two courses of appropriate antibiotics 1
• Recurrent sinusitis (≥3 episodes per year) 1
• Suspected complications (orbital cellulitis, meningitis, severe frontal/ethmoidal/sphenoidal sinusitis) 2, 1
• Need for sinus aspiration/culture in immunocompromised patients 1
• Evaluation for underlying allergic rhinitis, immunodeficiency, or anatomical abnormalities 1, 5