What is the treatment for a sinus infection?

Treatment for Sinus Infection

For acute bacterial sinusitis, amoxicillin 500 mg twice daily (mild disease) or 875 mg twice daily (moderate disease) for 10-14 days is the first-line treatment, but antibiotics should only be started when symptoms persist ≥10 days without improvement, severe symptoms occur for ≥3 consecutive days, or "double sickening" (worsening after initial improvement) is present. 1

Confirm Bacterial vs. Viral Sinusitis First

Most acute rhinosinusitis (98-99.5%) is viral and resolves spontaneously within 7-10 days without antibiotics 1. Antibiotics should only be prescribed when one of three patterns confirms bacterial infection: 1, 2

• Persistent symptoms: Nasal discharge, congestion, facial pain/pressure, or cough lasting ≥10 days without clinical improvement 1, 3
• Severe symptoms: Fever ≥39°C (102.2°F) with purulent nasal discharge and facial pain for ≥3 consecutive days 1, 4
• "Double sickening": Initial improvement from viral URI followed by worsening symptoms 1, 4

Common pitfall: Do not prescribe antibiotics for symptoms lasting <10 days unless severe symptoms are present, as this contributes to antimicrobial resistance without clinical benefit 1.

First-Line Antibiotic Treatment

Standard Therapy

• Amoxicillin 500 mg twice daily for mild disease 1, 2
• Amoxicillin 875 mg twice daily for moderate disease 1, 2
• Duration: 10-14 days or until symptom-free for 7 days 1, 2

High-Risk Patients Requiring Enhanced Coverage

Use high-dose amoxicillin-clavulanate 875 mg/125 mg twice daily for patients with: 1, 2

• Recent antibiotic use within 4-6 weeks 1
• Moderate-to-severe disease 1
• Age <2 years or >65 years 1
• Daycare attendance 1
• High local prevalence of resistant S. pneumoniae 1

Penicillin-Allergic Patients

Non-Severe Allergy (Rash, Mild Reactions)

Second- or third-generation cephalosporins are safe and effective: 1

• Cefuroxime-axetil (second-generation) 1, 2
• Cefpodoxime-proxetil or cefdinir (third-generation, superior H. influenzae coverage) 1, 2

The risk of cross-reactivity between penicillins and second/third-generation cephalosporins is negligible 1.

Severe Beta-Lactam Allergy (Anaphylaxis)

Respiratory fluoroquinolones are the treatment of choice: 1

• Levofloxacin 500 mg once daily for 10-14 days 1, 2
• Moxifloxacin 400 mg once daily for 10 days 1

Critical caveat: Fluoroquinolones provide 90-92% predicted clinical efficacy but should be reserved for severe allergies or treatment failures to prevent resistance development 1.

What NOT to Use in Penicillin Allergy

• Azithromycin: Explicitly contraindicated due to 20-25% resistance rates for S. pneumoniae and H. influenzae 1, 2
• Trimethoprim-sulfamethoxazole: High resistance rates (50% for S. pneumoniae, 27% for H. influenzae) 1
• First-generation cephalosporins (cephalexin): Inadequate coverage against H. influenzae (50% β-lactamase producing) 1

Treatment Failure Protocol

If no improvement after 3-5 days, switch antibiotics: 1, 2

Second-Line Options

1. High-dose amoxicillin-clavulanate (if not already used): 875 mg/125 mg twice daily or 2000 mg/125 mg twice daily 1, 2
2. Respiratory fluoroquinolones: Levofloxacin 500-750 mg once daily or moxifloxacin 400 mg once daily 1
3. Ceftriaxone 1-2 g IM/IV once daily for 5 days (for patients unable to tolerate oral medications or with severe disease) 1

Reassessment timeline: 1, 2

• At 3-5 days: If no improvement, switch antibiotics 1
• At 7 days: Confirm diagnosis if symptoms persist or worsen 1

Adjunctive Therapies (Use in ALL Patients)

Intranasal Corticosteroids (Strongly Recommended)

Mometasone, fluticasone, or budesonide twice daily reduces mucosal inflammation and improves symptom resolution 1, 2, 5. This has strong evidence from multiple randomized controlled trials and should be used as adjunct to antibiotics in both acute and chronic sinusitis 1, 5.

Saline Nasal Irrigation

Provides symptomatic relief and mechanically removes mucus 1, 2, 5. Hypertonic saline may improve mucociliary clearance more effectively than normal saline 5.

Analgesics

Acetaminophen or NSAIDs for pain and fever relief 1, 2.

Decongestants

• Oral: Pseudoephedrine provides symptomatic relief 1, 2
• Topical: Oxymetazoline, but limit to 5 days maximum to avoid rebound congestion (rhinitis medicamentosa) 2

Oral Corticosteroids (Selective Use)

Short-term oral corticosteroids (typically 5 days) may be reasonable for patients with: 1, 2

• Marked mucosal edema 1
• Nasal polyposis 1
• Failure to respond to initial antibiotic treatment 1

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

Special Situations

Frontal, Ethmoidal, or Sphenoidal Sinusitis

Consider fluoroquinolones (levofloxacin or moxifloxacin) as first-line therapy due to potential for serious complications 1, 2.

Pediatric Dosing

• Standard amoxicillin: 45 mg/kg/day in 2 divided doses 1
• High-dose amoxicillin: 80-90 mg/kg/day in 2 divided doses (for high-risk children) 1
• High-dose amoxicillin-clavulanate: 80-90 mg/kg/day of amoxicillin component with 6.4 mg/kg/day clavulanate in 2 divided doses 1

Watchful Waiting Option

For uncomplicated acute bacterial sinusitis, watchful waiting without immediate antibiotics is appropriate when follow-up can be assured 1. Start antibiotics only if no improvement by 7 days or worsening at any time 1. The number needed to treat with antibiotics is 10-15 to get one additional person better after 7-15 days 1.

When to Refer to Specialist

Refer to otolaryngology when: 1, 2, 5

• Symptoms refractory to two courses of appropriate antibiotics 1
• Recurrent sinusitis (≥3 episodes per year) 1
• Suspected complications (orbital cellulitis, meningitis, abscess) 1
• Need for sinus aspiration/culture in immunocompromised patients 1
• Chronic sinusitis significantly affecting quality of life 5

Critical Pitfalls to Avoid

• Do not prescribe antibiotics for viral rhinosinusitis lasting <10 days unless severe symptoms present 1
• Do not use mucus color alone to determine antibiotic need—color reflects neutrophils, not bacteria 1
• Complete the full antibiotic course even after symptoms improve to prevent relapse 1, 6
• Avoid fluoroquinolone overuse in patients without allergies to prevent resistance 1
• Do not extend topical decongestants beyond 5 days 2
• Reassess at 3-5 days if no improvement—do not continue ineffective therapy 1, 2