What is the recommended management for acute and chronic sinusitis, including indications for antibiotics, appropriate antibiotic choices, and adjunctive therapies?

Treatment of Sinusitis

Acute Bacterial Sinusitis: First-Line Management

Amoxicillin-clavulanate 875 mg/125 mg twice daily for 5-10 days is the preferred first-line antibiotic for acute bacterial sinusitis in adults, providing 90-92% predicted clinical efficacy against the major pathogens. 1

Confirming the Diagnosis Before Prescribing Antibiotics

Before initiating antibiotics, confirm that the patient meets at least one of three diagnostic criteria for acute bacterial rhinosinusitis (ABRS):

• Persistent symptoms ≥10 days without improvement (purulent nasal discharge with nasal obstruction or facial pain/pressure) 1, 2
• Severe symptoms for ≥3-4 consecutive days (fever ≥39°C with purulent nasal discharge and facial pain) 1
• "Double sickening" – worsening after initial improvement from a viral upper respiratory infection 1, 2

Critical context: 98-99.5% of acute rhinosinusitis is viral and resolves spontaneously within 7-10 days without antibiotics. 1, 2 Do not prescribe antibiotics for symptoms lasting <10 days unless severe features are present. 1

Standard Antibiotic Regimens

For most adults:

• Amoxicillin-clavulanate 875 mg/125 mg twice daily for 5-10 days 1
• Treatment duration: continue until symptom-free for 7 days (typically 10-14 days total) 1
• Recent evidence supports shorter 5-7 day courses with comparable efficacy and fewer adverse effects 1

High-dose regimen for specific risk factors:

• Use amoxicillin-clavulanate 2 g/125 mg twice daily for patients with: 1
  • Recent antibiotic use within past 4-6 weeks
  • Age >65 years
  • Moderate-to-severe symptoms
  • Comorbid conditions or immunocompromised state

Pediatric dosing:

• Standard: amoxicillin 45 mg/kg/day divided twice daily 1
• High-dose: amoxicillin 80-90 mg/kg/day divided twice daily for high-risk children (age <2 years, daycare attendance, recent antibiotic use, or high local resistance) 1
• High-dose amoxicillin-clavulanate: 80-90 mg/kg/day amoxicillin component with 6.4 mg/kg/day clavulanate divided twice daily 1
• Treatment duration: minimum 10-14 days for children 1

Penicillin-Allergic Patients

For non-severe (non-Type I) penicillin allergy:

• Second- or third-generation cephalosporins are preferred due to negligible cross-reactivity: 1
  • Cefuroxime-axetil
  • Cefpodoxime-proxetil
  • Cefdinir
  • Cefprozil

For severe (Type I/anaphylactic) penicillin allergy:

• Respiratory fluoroquinolones: 1
  • Levofloxacin 500 mg once daily for 10-14 days
  • Moxifloxacin 400 mg once daily for 10 days
• These provide 90-92% predicted clinical efficacy against multidrug-resistant S. pneumoniae 1

Doxycycline as a suboptimal alternative:

• Doxycycline 100 mg once daily for 10 days achieves only 77-81% predicted clinical efficacy (compared to 90-92% for first-line agents) 1
• Reserve for penicillin-allergic patients when cephalosporins are contraindicated and fluoroquinolones must be avoided 1
• Contraindicated in children <8 years due to tooth enamel discoloration risk 1

Antibiotics to Avoid

Never use as first-line therapy:

• Azithromycin and other macrolides – resistance rates 20-25% for both S. pneumoniae and H. influenzae 1
• Trimethoprim-sulfamethoxazole – 50% resistance for S. pneumoniae and 27% for H. influenzae 1
• First-generation cephalosporins (cephalexin) – inadequate coverage against H. influenzae (≈50% produce β-lactamase) 1
• Clindamycin monotherapy – lacks activity against H. influenzae and M. catarrhalis 1

Watchful Waiting Strategy

For adults with uncomplicated ABRS, initial observation without immediate antibiotics is equally appropriate when reliable follow-up can be ensured. 1, 2

• Start antibiotics only if no improvement by day 7 or symptoms worsen at any time 1
• Number needed to treat with antibiotics is 10-15 to achieve one additional cure over 7-15 days 1
• This approach reduces unnecessary antibiotic exposure while maintaining safety 1

Essential Adjunctive Therapies (Add to All Patients)

Intranasal corticosteroids are strongly recommended as adjunctive therapy in both acute and chronic sinusitis, regardless of antibiotic use. 1

• Intranasal corticosteroids (mometasone, fluticasone, or budesonide) twice daily reduce mucosal inflammation and improve symptom resolution 1
• Supported by strong evidence from multiple randomized controlled trials 1

Additional supportive measures:

• Saline nasal irrigation 2-3 times daily for symptomatic relief and mucus clearance 1, 3
• Analgesics (acetaminophen or ibuprofen) for pain and fever control 1, 2
• Decongestants (oral or topical); limit topical agents to ≤3 days to avoid rebound congestion 1, 4
• Adequate hydration and warm facial compresses 1

Monitoring and Treatment Failure Protocol

Reassess at 3-5 days:

• If no improvement, switch to second-line therapy immediately 1
• Options: high-dose amoxicillin-clavulanate or respiratory fluoroquinolone 1

Reassess at 7 days:

• If symptoms persist or worsen, reconfirm diagnosis and exclude complications 1, 2
• Consider imaging (CT) only if complications suspected or alternative diagnosis likely 1, 2

Pediatric reassessment:

• Reassess at 72 hours; if no improvement or worsening, switch to high-dose amoxicillin-clavulanate 1

Second-Line Treatment After Amoxicillin-Clavulanate Failure

After 3-5 days of amoxicillin-clavulanate without improvement, switch to a respiratory fluoroquinolone: 1

• Levofloxacin 500 mg once daily for 10-14 days
• Moxifloxacin 400 mg once daily for 10 days
• These provide 90-92% predicted efficacy against drug-resistant S. pneumoniae and β-lactamase-producing organisms 1

Alternative second-line options:

• Third-generation cephalosporins (cefpodoxime-proxetil or cefdinir) provide superior activity against H. influenzae 1
• Ceftriaxone 1-2 g IM/IV once daily for 5 days for patients unable to tolerate oral medications 1

When to Refer to Otolaryngology

Refer patients when any of the following occur: 1, 2

• No improvement after 7 days of appropriate second-line antibiotic therapy
• Worsening symptoms at any point during treatment
• Suspected complications (orbital cellulitis, meningitis, intracranial abscess, severe headache, visual changes, periorbital swelling, altered mental status)
• Recurrent sinusitis (≥3 episodes per year) requiring evaluation for underlying allergic rhinitis, immunodeficiency, or anatomic abnormalities

Chronic Rhinosinusitis: A Fundamentally Different Approach

Antibiotics should NOT be routinely prescribed for chronic rhinosinusitis (CRS) and should only be used when significant purulent nasal discharge is present on examination. 5

Primary Treatment for Chronic Sinusitis

Intranasal corticosteroids and saline irrigation are the cornerstones of chronic sinusitis management, not antibiotics. 5

• Intranasal corticosteroids (mometasone furoate) should be the first-line therapeutic intervention 5, 6
• Saline nasal irrigation facilitates mechanical removal of mucus and prevents crusting 5
• Chronic sinusitis is primarily an inflammatory condition rather than an infectious disease 5

When Antibiotics May Be Considered in Chronic Sinusitis

Reserve antibiotics for true acute bacterial exacerbations or when there is evidence of bacterial superinfection with systemic symptoms (high fever, severe facial pain, periorbital complications). 6

• Prescribe antibiotics only when purulent nasal discharge is present on direct examination 5
• If indicated: amoxicillin-clavulanate 875/125 mg twice daily for 10-14 days 5, 6
• Treatment duration: 10-14 days or until symptom-free for 7 days 5, 6

Evidence quality: The evidence supporting antibiotic use in chronic sinusitis is notably poor, with multiple systematic reviews indicating limited quantity and quality of data. 5 Conservative therapy with antibiotics alone is successful in only one-third of chronic sinusitis cases. 5

Additional Considerations for Chronic Sinusitis

• Consider short-term oral corticosteroids for marked mucosal edema or severe symptoms in patients who fail to respond to intranasal corticosteroids and saline irrigation 5, 6
• Evaluate for underlying allergic rhinitis, anatomic abnormalities, or immunodeficiency if symptoms are recurrent 5, 6, 2
• Confirm diagnosis with objective documentation using anterior rhinoscopy, nasal endoscopy, or CT scan before prescribing antibiotics 5, 2

Critical Pitfalls to Avoid

• Do not prescribe antibiotics based solely on CT findings – ≈87% of viral URIs show sinus abnormalities on imaging 1
• Do not obtain routine imaging (X-ray or CT) for uncomplicated acute rhinosinusitis – reserve for suspected complications or alternative diagnoses 1, 2
• Do not use fluoroquinolones as first-line therapy in patients without documented β-lactam allergies to prevent resistance development 1
• Ensure adequate treatment duration (≥5 days for adults, ≥10 days for children) to prevent relapse 1
• Avoid overuse of antibiotics in chronic sinusitis unless there is clear evidence of bacterial infection with purulent discharge 5
• Waiting beyond 7 days to change therapy in non-responders delays effective treatment and may allow complications to develop 1