What is the recommended treatment for acute sinusitis?

Treatment of Acute Sinusitis

First-Line Antibiotic Selection

Amoxicillin-clavulanate is the preferred first-line antibiotic for acute bacterial sinusitis in both adults and children, not amoxicillin alone. 1

• For adults: Amoxicillin-clavulanate 875 mg/125 mg twice daily is recommended as the standard dose 2
• For children: High-dose amoxicillin-clavulanate 80-90 mg/kg/day of the amoxicillin component with 6.4 mg/kg/day clavulanate in 2 divided doses is preferred, particularly in areas with high prevalence of resistant S. pneumoniae or in children with risk factors (age <2 years, daycare attendance, recent antibiotic use) 2
• The clavulanate component provides critical coverage against β-lactamase-producing H. influenzae and M. catarrhalis, which have become increasingly prevalent 2

When to Use High-Dose Therapy

High-dose amoxicillin-clavulanate (2 g orally twice daily for adults or 90 mg/kg/day twice daily for children) should be used when 1:

• Recent antibiotic exposure within the past month
• Geographic areas with high rates of penicillin-resistant S. pneumoniae (>10%)
• Severe infection (fever >39°C, severe facial pain)
• Immunocompromised patients

Treatment Duration

Treatment duration differs significantly between adults and children:

• Adults: 5-7 days for uncomplicated acute bacterial sinusitis 1
• Children: 10-14 days remains the recommended duration 1
• Some guidelines suggest treating until symptom-free for 7 days, which typically results in 10-14 days total 2

The shorter duration in adults is supported by evidence showing comparable efficacy with fewer side effects 2

Penicillin-Allergic Patients

For documented penicillin allergy, second- or third-generation cephalosporins are preferred alternatives, NOT macrolides like azithromycin. 2

Recommended alternatives:

• Second-generation: Cefuroxime-axetil 2, 3
• Third-generation: Cefpodoxime-proxetil, cefdinir, or cefprozil 2, 3
• The risk of cross-reactivity between penicillins and second/third-generation cephalosporins is negligible 2

For severe beta-lactam allergy:

• Respiratory fluoroquinolones (levofloxacin 500-750 mg once daily or moxifloxacin) should be reserved for this specific situation 2, 3
• Doxycycline 100 mg once daily for 10 days is an acceptable alternative but has a predicted bacteriologic failure rate of 20-25%, making it suboptimal when better alternatives exist 2

Critical Pitfall:

Azithromycin and other macrolides should NOT be used for acute bacterial sinusitis due to 20-25% resistance rates in S. pneumoniae and H. influenzae 2

Second-Line Treatment for Treatment Failure

If no improvement occurs after 48-72 hours or symptoms worsen, or if there is failure to improve after 3-5 days of initial therapy, switch to alternative management: 1

Second-line options:

• High-dose amoxicillin-clavulanate (if not already used) at 4 g/250 mg per day 2
• Respiratory fluoroquinolones: Levofloxacin 500-750 mg once daily or moxifloxacin 2, 4
• Fluoroquinolones provide 90-92% predicted clinical efficacy and excellent coverage against multi-drug resistant S. pneumoniae (MDRSP) 2

When to use fluoroquinolones as first-line:

• Frontal, ethmoidal, or sphenoidal sinusitis (not maxillary) due to potential for serious complications 2, 3
• Multi-drug resistant organisms documented
• Treatment failure with first-line agents

Adjunctive Therapies

Intranasal corticosteroids are recommended as adjuncts to antibiotic therapy, particularly in patients with allergic rhinitis. 1

Recommended adjunctive treatments:

• Intranasal saline irrigation (physiologic or hypertonic) for adults 1
• Intranasal corticosteroids for all patients, especially those with allergic rhinitis 1
• Short-term oral corticosteroids (e.g., dexamethasone 4 mg) may be considered for acute hyperalgic sinusitis (severe pain) or marked mucosal edema when combined with appropriate antibiotics 2
• Analgesics (acetaminophen, NSAIDs) for pain relief 2

What NOT to use:

Topical or oral decongestants and antihistamines are NOT recommended as adjunctive treatment in acute bacterial sinusitis 1

• Topical decongestants should not exceed 3-5 days if used, to avoid rebound congestion (rhinitis medicamentosa) 3, 5

When to Refer to a Specialist

Referral to an otolaryngologist, infectious disease specialist, or allergist is indicated when: 1

• Seriously ill or immunocompromised patients
• Continued deterioration despite extended courses of antimicrobial therapy
• Recurrent bouts of acute rhinosinusitis (≥3 episodes per year) with clearing between episodes 2, 3
• Need for direct sinus aspiration cultures in treatment failures 1

Diagnostic Confirmation

Antibiotics should only be initiated when acute bacterial sinusitis is confirmed by one of three clinical patterns: 2

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

Most acute rhinosinusitis cases are viral and resolve without antibiotics within 7 days 2

Critical Pitfalls to Avoid

• Do not use routine MRSA coverage during initial empiric therapy 1
• Do not use azithromycin or macrolides as first-line therapy due to high resistance rates 2
• Do not use fluoroquinolones routinely as first-line therapy; reserve for treatment failures, severe disease, or complicated sinusitis to prevent resistance development 2, 3
• Ensure adequate treatment duration (minimum 5 days for adults, 10-14 days for children) to prevent relapse 1, 2
• Reassess at 3 days (pediatrics) or 3-5 days (adults) if no improvement to avoid treatment failure 1, 2
• Complete the full course of antibiotics even after symptoms improve to prevent relapse 2