What is the recommended treatment for sinusitis, including acute bacterial and chronic cases?

Treatment of Sinusitis

Acute Bacterial Sinusitis

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 causative pathogens. 1

Confirming the Diagnosis Before Prescribing Antibiotics

Before initiating antibiotics, confirm that the patient meets at least one of the following criteria for acute bacterial rhinosinusitis (ABRS), as 98-99.5% of acute rhinosinusitis cases are viral and resolve spontaneously within 7-10 days 1:

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

First-Line Antibiotic Selection

• Standard regimen: Amoxicillin-clavulanate 875 mg/125 mg twice daily for 5-10 days (or until symptom-free for 7 days, typically 10-14 days total) 1
• High-dose regimen: Use amoxicillin-clavulanate 2 g/125 mg twice daily for patients with recent antibiotic use within the past month, age >65 years, moderate-to-severe symptoms, comorbid conditions, or immunocompromised state 1
• Recent evidence supports shorter 5-7 day courses with comparable efficacy and fewer adverse effects 1

Alternatives for Penicillin Allergy

• Non-severe (non-Type I) penicillin allergy: Second- or third-generation cephalosporins (cefuroxime, cefpodoxime, cefdinir, or cefprozil) for 10 days, as cross-reactivity is negligible 1
• Severe (Type I/anaphylactic) penicillin allergy: Respiratory fluoroquinolones—levofloxacin 500 mg once daily for 10-14 days or moxifloxacin 400 mg once daily for 10 days 1
• Doxycycline 100 mg once daily for 10 days is an acceptable but suboptimal alternative with 77-81% predicted efficacy (compared to 90-92% for first-line agents), reserved for penicillin-allergic patients when cephalosporins are contraindicated 1

Antibiotics to Avoid

• Azithromycin and other macrolides should not be used due to resistance rates of 20-25% for both Streptococcus pneumoniae and Haemophilus influenzae 1
• Trimethoprim-sulfamethoxazole has 50% resistance for S. pneumoniae and 27% for H. influenzae 1
• First-generation cephalosporins (cephalexin) provide inadequate coverage against H. influenzae, as nearly 50% of strains are β-lactamase producing 1

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. 1 Start antibiotics only if no improvement occurs by day 7 or if symptoms worsen at any time 1. The number needed to treat with antibiotics is 10-15 to achieve one additional cure over 7-15 days, reflecting the high rate of spontaneous recovery 1.

Essential Adjunctive Therapies (Add to All Patients)

• Intranasal corticosteroids (mometasone, fluticasone, or budesonide) twice daily significantly reduce mucosal inflammation and improve symptom resolution, supported by strong evidence from multiple randomized controlled trials 2, 1
• Saline nasal irrigation 2-3 times daily provides symptomatic relief and aids mucus clearance 2, 1
• Analgesics (acetaminophen or ibuprofen) for pain and fever control 2, 1
• Decongestants (oral or topical) may provide symptomatic relief; limit topical agents to ≤3 days to avoid rebound congestion 2, 3

Monitoring and Treatment Failure Protocol

• Reassess at 3-5 days: If no improvement, switch to high-dose amoxicillin-clavulanate (2 g/125 mg twice daily) or a respiratory fluoroquinolone 1
• Reassess at 7 days: If symptoms persist or worsen, reconfirm the diagnosis, exclude complications (orbital cellulitis, meningitis, brain abscess), and consider imaging or ENT referral 1
• Worsening at any time requires immediate evaluation for complications and switching antibiotics 1

Pediatric Dosing

• Standard-dose amoxicillin: 45 mg/kg/day divided into 2 doses for uncomplicated disease 1
• High-dose amoxicillin: 80-90 mg/kg/day divided into 2 doses for children <2 years, in daycare, with recent antibiotic use, or in areas with high resistance 1
• High-dose amoxicillin-clavulanate: 80-90 mg/kg/day of amoxicillin component with 6.4 mg/kg/day clavulanate divided into 2 doses for high-risk children 1
• Treatment duration: Minimum 10-14 days for children (longer than adult courses) 1
• Reassess at 72 hours: If no improvement or worsening, switch to high-dose amoxicillin-clavulanate 1

Common Pitfalls to Avoid

• Do not prescribe antibiotics for symptoms lasting <10 days unless severe features are present (fever ≥39°C with purulent discharge for ≥3 consecutive days) 1
• Do not obtain routine imaging (X-ray or CT) for uncomplicated acute bacterial sinusitis; reserve imaging for suspected complications or alternative diagnoses 1
• Do not use fluoroquinolones as first-line therapy in patients without documented β-lactam allergies to prevent resistance development 1
• Ensure adequate treatment duration (minimum 5 days for adults, 10 days for children) to prevent relapse 1

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Chronic Sinusitis

Intranasal corticosteroids are the cornerstone of treatment for chronic sinusitis, defined as symptoms persisting ≥8 weeks, due to their anti-inflammatory effects and documented efficacy in relieving nasal congestion. 4

First-Line Therapy

• Intranasal corticosteroids (mometasone, fluticasone, or budesonide) twice daily are the primary treatment for chronic sinusitis 4
• High-volume saline irrigation (hypertonic saline) prevents crusting of secretions and facilitates mechanical removal of mucus, potentially improving mucociliary clearance more effectively than normal saline 4

Role of Antibiotics in Chronic Sinusitis

• For chronic infectious sinusitis, longer duration of antibiotic therapy (often >3 weeks) may be required, with attention to anaerobic pathogens 2, 4, 5, 6
• Antibiotics play a controversial role in non-infectious chronic sinusitis and should not be the primary treatment 4
• Chronic hyperplastic eosinophilic rhinosinusitis does not respond to antibiotics and requires systemic corticosteroids 2

Adjunctive Therapies

• Decongestants may provide symptomatic relief by widening ostia and reducing turbinate swelling, but should be used cautiously due to potential systemic effects 4, 3
• Antihistamines are beneficial for patients with an allergic rhinitis component 4
• Mucolytics and expectorants may provide symptomatic benefit in selected cases 4

Evaluation for Underlying Conditions

• Patients with chronic or recurrent sinusitis (≥3 episodes per year) should be evaluated for allergic rhinitis, gastroesophageal reflux disease (GERD), immunodeficiency, and anatomic abnormalities 2, 4
• Tests for immunodeficiency (quantitative immunoglobulin measurement, functional antibody tests, HIV testing) should be considered in cases of recurrent sinusitis 2
• Quantitative sweat chloride tests and genetic testing for cystic fibrosis should be considered in children with nasal polyps or colonization with Pseudomonas species 2

Surgical Intervention

• Medically resistant sinusitis may respond to functional endoscopic sinus surgery, particularly in cases of localized persistent disease within the ostiomeatal complex 2

When to Refer to a Specialist

• Specialist referral is indicated when sinusitis is refractory to two courses of appropriate antibiotics, recurrent (≥3 episodes per year), or significantly affects quality of life 4
• Consultation should be sought when there is a need to clarify the allergic or immunologic basis for sinusitis 2, 4
• Refer for suspected complications (orbital cellulitis, meningitis, intracranial abscess) or when imaging shows anatomic abnormalities requiring surgical correction 2

Critical Pitfalls

• Overuse of antibiotics should be avoided unless there is clear evidence of bacterial infection 4
• Chronic sinusitis should be considered a chronic inflammatory condition rather than a bacterial infection, so routine antibiotic therapy should be avoided 7
• Empiric antibiotic therapy should be prescribed only when acute exacerbation of chronic sinusitis occurs, targeting the usual bacteria causing acute sinusitis 7