What is the treatment for a sinus infection?

Treatment of Sinus Infection (Acute Bacterial Sinusitis)

Amoxicillin 500 mg twice daily for 10-14 days is the first-line treatment for most adults with acute bacterial sinusitis, or high-dose amoxicillin-clavulanate (875 mg/125 mg twice daily) for more severe infections or recent antibiotic exposure. 1

Confirming the Diagnosis Before Treatment

Before starting antibiotics, ensure the patient meets criteria for bacterial sinusitis (not viral):

• Persistent symptoms ≥10 days without improvement (nasal discharge, congestion, facial pain/pressure, cough) 1, 2
• Severe symptoms for ≥3 consecutive days (fever >39°C, purulent nasal discharge, severe facial pain) 1
• "Double sickening" - worsening after initial improvement from a viral upper respiratory infection 1

Most acute rhinosinusitis is viral and resolves within 7 days without antibiotics. 1

First-Line Antibiotic Treatment

Standard Therapy (Uncomplicated Cases)

• Amoxicillin 500 mg twice daily for mild disease without recent antibiotic exposure 1
• Amoxicillin 875 mg twice daily for moderate disease 1
• Duration: 10-14 days (treat until symptom-free for 7 days) 1, 2

High-Dose Therapy (Severe Disease or Risk Factors)

• Amoxicillin-clavulanate 875 mg/125 mg twice daily for 5-10 days 1
• Use this for patients with recent antibiotic exposure, severe symptoms, or areas with high prevalence of resistant S. pneumoniae 1, 2
• The clavulanate component covers β-lactamase-producing H. influenzae and M. catarrhalis 1

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 areas with 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 for children <2 years, daycare attendance, or recent antibiotic use 1

Penicillin-Allergic Patients

Non-Severe Allergy

• Second-generation cephalosporins: Cefuroxime-axetil 1
• Third-generation cephalosporins: Cefpodoxime-proxetil or cefdinir (superior activity against H. influenzae) 1
• The risk of cross-reactivity with cephalosporins in penicillin-allergic patients is negligible 1

Severe Beta-Lactam Allergy

• Levofloxacin 500 mg once daily for 10-14 days 1
• Moxifloxacin is an alternative fluoroquinolone 1
• Reserve fluoroquinolones for documented severe allergy to avoid resistance development 1

Avoid These Agents

• Azithromycin and macrolides should NOT be used due to 20-25% resistance rates in S. pneumoniae and H. influenzae 1
• Doxycycline has a 20-25% predicted bacteriologic failure rate and limited activity against H. influenzae 1

Treatment Failure Protocol

If no improvement after 3-5 days (adults) or 72 hours (children):

• Switch to amoxicillin-clavulanate (high-dose: 875 mg/125 mg twice daily or 4 g/250 mg per day) 1, 2
• Alternative: Respiratory fluoroquinolones (levofloxacin 500-750 mg once daily or moxifloxacin) 1
• Fluoroquinolones provide 90-92% predicted clinical efficacy and excellent coverage against multi-drug resistant S. pneumoniae 1
• Reassess the diagnosis - consider imaging or specialist referral 1

Adjunctive Therapies (Use in ALL Patients)

Intranasal Corticosteroids

• Recommended as adjunct to antibiotics in both acute and chronic sinusitis 1, 2
• Reduces inflammation, promotes drainage, and may decrease need for antibiotics 1

Supportive Measures

• Saline nasal irrigation for symptomatic relief and mechanical removal of mucus 2, 3
• Analgesics (acetaminophen, NSAIDs) for pain relief 1, 2
• Adequate hydration, warm facial packs, steamy showers 2
• Decongestants (oral or topical) - limit topical use to ≤5 days to avoid rebound congestion 2

Short-Term Oral Corticosteroids

• Consider for acute hyperalgic sinusitis (severe pain) or marked mucosal edema 1
• Dexamethasone 4 mg may be used as short-term adjunctive therapy (NOT monotherapy) 1

Special Situations

Complicated Sinusitis (Frontal, Ethmoidal, Sphenoidal)

• Fluoroquinolones (levofloxacin or moxifloxacin) are preferred due to risk of serious complications 1
• These locations require broader coverage than maxillary sinusitis 1, 2

Watchful Waiting Option

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

Critical Pitfalls to Avoid

• Do NOT use antibiotics for viral rhinosinusitis - most cases resolve within 7 days 1, 2
• Do NOT use azithromycin or macrolides as first-line therapy due to high resistance 1
• Do NOT use fluoroquinolones routinely - reserve for treatment failures, severe disease, or complicated sinusitis 1
• Ensure adequate treatment duration (minimum 5-7 days, typically 10-14 days) to prevent relapse 1, 2
• Limit topical decongestants to ≤5 days to avoid rhinitis medicamentosa 2
• Complete the full antibiotic course even after symptom improvement to prevent resistance 1, 4
• Take amoxicillin-clavulanate with food to reduce gastrointestinal upset 4

When to Refer to a Specialist

• Sinusitis refractory to usual antibiotic treatment 1, 3
• Recurrent sinusitis (≥3 episodes per year) - evaluate for underlying allergic rhinitis, immunodeficiency, or anatomic abnormalities 1, 3
• Sinusitis associated with unusual opportunistic infections 1
• Need to clarify allergic or immunologic basis for sinusitis 1
• Significantly affects quality of life despite appropriate medical management 3