When are antibiotics appropriate for sinusitis?

When Are Antibiotics Appropriate for Sinusitis?

Antibiotics are NOT appropriate for most cases of sinusitis and should be reserved only for patients with severe symptoms, persistent symptoms lasting more than 10 days without improvement, or worsening symptoms after initial improvement. 1, 2

Diagnostic Criteria for Bacterial Sinusitis

Bacterial sinusitis should be suspected in patients with:

1. Persistent symptoms - Nasal discharge (of any quality) or daytime cough or both for at least 10 days without evidence of improvement 1, 2
2. Severe symptoms - High fever (≥39°C/102.2°F) with purulent nasal discharge for at least 3-4 consecutive days 2
3. Worsening symptoms - Initial improvement followed by worsening of symptoms (double sickening) 1, 2

Additional clinical findings that increase the likelihood of bacterial infection include:

• Unilateral sinus tenderness
• Maxillary tooth pain
• Unilateral facial pain with purulent nasal discharge 1

Antibiotic Decision Algorithm

Step 1: Assess Symptom Pattern

• Mild symptoms lasting <7 days: Likely viral, antibiotics NOT indicated 1, 3
• Moderate symptoms lasting 7-10 days: Consider additional observation without antibiotics 1
• Symptoms meeting any of the three criteria above: Consider antibiotics 2

Step 2: For Those Meeting Criteria for Antibiotics, Consider Risk Factors for Resistant Organisms

Risk factors include:

• Age <2 years (for pediatric patients)
• Recent antibiotic use (within 4 weeks)
• Daycare attendance
• Moderate to severe illness 2

First-Line Antibiotic Therapy

When antibiotics are indicated, first-line therapy should be:

• Amoxicillin or amoxicillin-clavulanate for 5-7 days 2
• For penicillin-allergic patients: Doxycycline, trimethoprim-sulfamethoxazole, or cefdinir/cefuroxime/cefpodoxime 1, 2

Monitoring and Reassessment

• Reassess patients within 72 hours of starting antibiotics 2
• If symptoms worsen or don't improve after 72 hours, consider:
  1. Switching to high-dose amoxicillin-clavulanate
  2. Reevaluating the diagnosis 2

Important Caveats

• Sinus radiography is NOT recommended for routine diagnosis due to high prevalence of abnormal findings in viral rhinosinusitis 1
• The gold standard for diagnosis (sinus puncture with aspiration) is rarely performed in primary care 1
• Most cases of acute sinusitis resolve spontaneously without antibiotics 3, 4
• The benefit of antibiotics is relatively small - studies show 88.7% of untreated patients improve spontomatically versus 96.2% of those receiving antibiotics 4
• Patients with poor oro-dental condition or recent antibiotic use may benefit most from antibiotics 4

Symptomatic Treatment

For all patients with sinusitis, regardless of antibiotic use, consider:

• Analgesics for pain relief
• Saline nasal irrigation
• Decongestants (though evidence for efficacy is limited) 1, 2

Remember that overuse of antibiotics contributes to antimicrobial resistance, and acute bacterial sinusitis is currently over-diagnosed and over-treated in primary care practice 3. The decision to prescribe antibiotics should balance the small clinical benefit against the risks of adverse effects and increasing antibiotic resistance.