What is the recommended treatment for a patient with bacterial rhinosinusitis?

Treatment for Bacterial Rhinosinusitis

Amoxicillin-clavulanate 875 mg/125 mg twice daily for 5-10 days is the preferred first-line antibiotic for acute bacterial rhinosinusitis in adults, with watchful waiting (no immediate antibiotics) being equally appropriate for uncomplicated cases when reliable follow-up can be assured. 1, 2, 3

Confirming the Diagnosis Before Prescribing Antibiotics

Before initiating antibiotic therapy, confirm the patient meets one of three diagnostic criteria for bacterial (not viral) rhinosinusitis 1, 3:

• Persistent symptoms ≥10 days without clinical improvement (purulent nasal discharge, nasal obstruction, facial pain/pressure) 1, 3
• Severe symptoms for ≥3-4 consecutive days at illness onset (fever ≥39°C [102°F] with purulent nasal discharge or facial pain) 1, 3
• "Double-sickening": worsening symptoms after initial improvement from a viral URI (new fever, headache, or increased nasal discharge after 5-6 days of improvement) 1, 3

Critical pitfall: 98-99.5% of acute rhinosinusitis is viral and resolves spontaneously within 7-10 days without antibiotics—do not prescribe antibiotics for symptoms <10 days unless severe features are present. 2, 4, 5

First-Line Antibiotic Treatment

Standard Therapy (No Risk Factors)

Amoxicillin-clavulanate 875 mg/125 mg twice daily for 5-10 days is the preferred first-line agent due to coverage of β-lactamase-producing Haemophilus influenzae and Moraxella catarrhalis, with 90-92% predicted clinical efficacy. 1, 2, 3

Alternative: Plain amoxicillin 500 mg twice daily (mild disease) or 875 mg twice daily (moderate disease) remains acceptable for uncomplicated cases without recent antibiotic exposure. 2

High-Dose Therapy (Risk Factors Present)

Use high-dose amoxicillin-clavulanate 2 g/125 mg twice daily for patients with 2, 3:

• Recent antibiotic use within past 4-6 weeks
• Age >65 years or <2 years
• Moderate-to-severe symptoms
• Daycare attendance (children)
• Comorbid conditions or immunocompromised state
• Geographic areas with high prevalence of penicillin-resistant S. pneumoniae

Treatment Duration

• Adults: 5-7 days for uncomplicated disease (shorter courses have comparable efficacy with fewer adverse effects) 2, 3
• Children: 10-14 days 2, 3
• Alternative guideline: Treat until symptom-free for 7 days (typically 10-14 days total) 1, 2

Penicillin-Allergic Patients

Non-Severe (Non-Type I) Allergy

Second- or third-generation cephalosporins are preferred due to negligible cross-reactivity risk 2, 3:

• Cefuroxime-axetil (second-generation) 2
• Cefpodoxime-proxetil or cefdinir (third-generation, superior H. influenzae coverage) 2, 3

Severe (Type I/Anaphylactic) Allergy

Respiratory fluoroquinolones 2, 3:

• Levofloxacin 500 mg once daily for 10-14 days (90-92% predicted efficacy) 2, 6
• Moxifloxacin 400 mg once daily for 10 days 2

Alternative: Doxycycline 100 mg once daily for 10 days (acceptable but suboptimal with 77-81% efficacy and limited H. influenzae activity) 2, 7

Do NOT use 2:

• Azithromycin or macrolides (20-25% resistance rates for S. pneumoniae and H. influenzae) 2, 8
• Trimethoprim-sulfamethoxazole (50% resistance for S. pneumoniae, 27% for H. influenzae) 2
• First-generation cephalosporins like cephalexin (inadequate H. influenzae coverage) 2

Watchful Waiting Strategy

For adults with uncomplicated acute bacterial sinusitis, watchful waiting without immediate antibiotics is an appropriate initial strategy when reliable follow-up can be assured. 2, 3, 4

• Start antibiotics only if no improvement by 7 days or symptoms worsen at any time 2, 4
• Provide symptomatic treatment during observation period 4

Essential Adjunctive Therapies (For ALL Patients)

These interventions improve outcomes regardless of antibiotic choice 2, 3, 4:

• Intranasal corticosteroids (mometasone, fluticasone, or budesonide twice daily): Reduce mucosal inflammation, increase symptom resolution from 66% to 73% at 15-21 days (NNT=14) 2, 4
• Saline nasal irrigation (hypertonic or physiologic saline): Facilitates mucus clearance, provides symptomatic relief 2, 3, 4
• Analgesics (acetaminophen or ibuprofen): Relieve pain and fever 2, 4
• Decongestants (use cautiously): Limit topical decongestants to 3-5 days to avoid rebound congestion 4, 7

Treatment Failure Protocol

Reassessment Timepoints

• 3-5 days (adults) or 72 hours (children): If no improvement or worsening, switch antibiotics immediately 1, 2, 3
• 7 days: Definitive assessment—if symptoms persist, reconfirm diagnosis and switch to second-line therapy 2, 3

Second-Line Antibiotics (After First-Line Failure)

Switch to 2, 3:

• High-dose amoxicillin-clavulanate (if not already used): 2 g/125 mg twice daily
• Respiratory fluoroquinolones: Levofloxacin 500 mg once daily or moxifloxacin 400 mg once daily for 10-14 days (90-92% efficacy against drug-resistant S. pneumoniae and β-lactamase-producing organisms) 2, 6
• Third-generation cephalosporins: Cefpodoxime or cefdinir (superior H. influenzae activity) 2

When to Refer to Otolaryngology

Refer if 2, 3, 4:

• No improvement after 7 days of appropriate second-line therapy
• Worsening symptoms at any time
• Suspected complications (orbital cellulitis, meningitis, brain abscess): periorbital edema, diplopia, severe headache, altered mental status 4
• Recurrent sinusitis (≥3 episodes per year) 2
• Symptoms persist >21-28 days despite appropriate treatment 4

Pediatric-Specific Dosing

• Standard amoxicillin: 45 mg/kg/day in 2 divided doses 2
• High-dose amoxicillin: 80-90 mg/kg/day in 2 divided doses (for age <2 years, daycare, recent antibiotic use, or high local resistance) 2, 3
• High-dose amoxicillin-clavulanate: 80-90 mg/kg/day of amoxicillin component with 6.4 mg/kg/day clavulanate in 2 divided doses 2, 3
• Ceftriaxone: 50 mg/kg IM/IV once daily for children unable to tolerate oral medications 2

Critical Pitfalls to Avoid

• Do not prescribe antibiotics for viral rhinosinusitis (symptoms <10 days without severe features)—this promotes antimicrobial resistance without clinical benefit 2, 3, 5
• Do not use fluoroquinolones as first-line therapy in patients without documented β-lactam allergies—reserve for treatment failures or severe allergies to prevent resistance 2, 3
• Do not use azithromycin due to 20-25% resistance rates 2, 8
• Do not continue ineffective therapy beyond 3-5 days—early reassessment prevents treatment failure and complications 2, 3
• Do not use colored nasal discharge alone as criterion for antibiotic prescription—color reflects neutrophils, not bacteria 2