When should antibiotics be started for acute bacterial sinusitis?

Antibiotic Timing for Acute Bacterial Rhinosinusitis

For uncomplicated acute bacterial rhinosinusitis (ABRS), clinicians should either offer watchful waiting for 7 days or prescribe immediate antibiotics based on symptom severity, with antibiotics indicated immediately only for severe symptoms or after 7 days if no improvement occurs with watchful waiting. 1

Initial Management Algorithm

• Watchful waiting approach (recommended for mild-moderate uncomplicated ABRS):

  • Delay antibiotics for up to 7 days after diagnosis while providing symptomatic treatment 1
  • Start antibiotics only if symptoms worsen at any time or fail to improve after 7 days 1
  • Ensure patient follow-up is available if watchful waiting is chosen 1

• Immediate antibiotic therapy (recommended for):

  • Patients with severe symptoms (high fever, purulent nasal discharge, facial pain) 2
  • Patients with persistent symptoms lasting ≥10 days without improvement 2
  • Patients with "double-sickening" (worsening after initial improvement) 2

Evidence Supporting Delayed Antibiotics

• Most ABRS cases resolve spontaneously without antibiotics 1
• The clinical benefit of antibiotics is small - only 1 in 10-15 patients benefit from antibiotic therapy compared to placebo 1
• Watchful waiting reduces unnecessary antibiotic use, adverse events, and bacterial resistance 1
• Cure or improvement rates at 7-15 days are 91% for antibiotic therapy vs 86% for placebo 1

When Antibiotics Are Started

• First-line therapy: Amoxicillin with or without clavulanate for 5-10 days 1, 2
• For mild disease: Standard-dose amoxicillin (1.5-4g/day) 2
• For risk factors for resistant pathogens: High-dose amoxicillin-clavulanate (4g/250mg per day) 2, 3
• Duration: 5-7 days for uncomplicated cases; 7-10 days for more severe disease 2, 4

Treatment Failure Management

• If no improvement occurs within 72 hours of initial antibiotic therapy, reassess the patient 3
• For patients initially managed with observation who fail to improve after 7 days, begin antibiotic therapy 1
• For patients initially managed with an antibiotic who fail to improve, change to a different antibiotic 1
• Consider respiratory fluoroquinolones for treatment failures (90-92% predicted clinical efficacy) 5

Common Pitfalls to Avoid

• Premature antibiotic use: Most cases of acute rhinosinusitis are viral and resolve without antibiotics 6
• Prolonged antibiotic courses: Short-course therapy (5-7 days) has similar effectiveness to longer courses (10-14 days) with fewer adverse events 4, 7
• Inadequate follow-up: Ensure patients on watchful waiting have clear instructions about when to start antibiotics and how to seek follow-up 1
• Overuse of broad-spectrum antibiotics: Reserve broader-spectrum antibiotics for treatment failures or patients with risk factors for resistant pathogens 8

Symptomatic Treatment During Watchful Waiting

• Acetaminophen or ibuprofen for pain and fever 1
• Saline irrigations to relieve symptoms and remove mucus 1
• Nasal decongestants (limit topical use to 3 days) 1, 8
• Nasal corticosteroids may provide benefit but require at least 15 days of use 1