What are the treatment guidelines for a patient with acute sinusitis?

Treatment Guidelines for Acute Sinusitis

Diagnosis Before Treatment: Confirm Bacterial Infection

Most acute sinusitis (98-99.5%) is viral and resolves spontaneously within 7-10 days without antibiotics—prescribe antibiotics only when bacterial infection is confirmed by one of three specific clinical patterns. 1, 2

• Persistent symptoms ≥10 days without clinical improvement 1, 2
• Severe symptoms (fever ≥39°C with purulent nasal discharge) for ≥3-4 consecutive days 1, 2
• "Double sickening": worsening symptoms after initial improvement from a viral upper respiratory infection 1, 2

Avoid imaging (X-ray or CT) for uncomplicated cases—diagnosis is clinical. 3, 4

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First-Line Antibiotic Treatment

Amoxicillin-clavulanate 875 mg/125 mg twice daily for 5-10 days is the preferred first-line antibiotic for acute bacterial sinusitis in adults. 1, 2

Standard Dosing

• Adults: Amoxicillin-clavulanate 875 mg/125 mg twice daily for 5-10 days 1, 2
• High-dose regimen (2 g amoxicillin/125 mg clavulanate twice daily) for patients with recent antibiotic use within past 4-6 weeks, age >65 years, moderate-to-severe symptoms, or immunocompromised state 1, 2
• Children: Amoxicillin 45 mg/kg/day in 2 divided doses (standard) or 80-90 mg/kg/day in 2 divided doses (high-dose for age <2 years, daycare attendance, or recent antibiotic use) 1, 2

Alternative First-Line for Mild Disease

• Plain amoxicillin 500 mg twice daily (mild disease) or 875 mg twice daily (moderate disease) is acceptable for uncomplicated cases without recent antibiotic exposure 1, 2

Treatment Duration

• 5-10 days for adults, with recent evidence supporting shorter 5-7 day courses showing comparable efficacy with fewer adverse effects 1, 2
• 10-14 days for children or until symptom-free for 7 days 1, 2, 5

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Watchful Waiting Option

Watchful waiting without immediate antibiotics is equally appropriate for uncomplicated acute bacterial sinusitis when reliable follow-up can be assured. 1, 2

• Start antibiotics only if no improvement by 7 days or symptoms worsen at any time 1, 2
• This approach reduces unnecessary antibiotic exposure while maintaining safety 1, 2

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Penicillin-Allergic Patients

Second- or third-generation cephalosporins are safe and preferred for patients with non-severe penicillin allergy. 1, 2

Non-Severe Penicillin Allergy (Rash, Delayed Reaction)

• Cefuroxime-axetil (second-generation cephalosporin) 1, 2
• Cefpodoxime-proxetil or cefdinir (third-generation cephalosporins) 1, 2
• Risk of cross-reactivity with cephalosporins is negligible in non-Type I allergies 1, 2

Severe Penicillin Allergy (Anaphylaxis, Type I Hypersensitivity)

• Levofloxacin 500 mg once daily or moxifloxacin 400 mg once daily for 10 days 1, 2
• Doxycycline 100 mg once daily for 10 days is an acceptable alternative, though with lower efficacy (77-81% vs. 90-92% for fluoroquinolones) 1, 2

What NOT to Use

• Azithromycin and macrolides: Resistance rates exceed 20-25% for S. pneumoniae and H. influenzae—explicitly contraindicated as first-line therapy 1, 2, 6
• Trimethoprim-sulfamethoxazole: 50% resistance for S. pneumoniae, 27% for H. influenzae 1, 2
• First-generation cephalosporins (cephalexin): Inadequate coverage against H. influenzae 1, 2

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Second-Line Treatment for Treatment Failure

If no improvement after 3-5 days of initial therapy, switch to high-dose amoxicillin-clavulanate or a respiratory fluoroquinolone. 1, 2

Reassessment Timeline

• 3-5 days: Switch antibiotics if no improvement or worsening symptoms 1, 2
• 7 days: Reconfirm diagnosis, exclude complications, consider imaging if symptoms persist 1, 2

Second-Line Options

• High-dose amoxicillin-clavulanate (2 g amoxicillin/125 mg clavulanate twice daily) for 10-14 days 1, 2
• Levofloxacin 500 mg once daily or moxifloxacin 400 mg once daily for 10 days (90-92% predicted clinical efficacy) 1, 2
• Third-generation cephalosporins (cefpodoxime, cefdinir) offer superior activity against H. influenzae 1, 2

Pediatric Treatment Failure

• Switch to high-dose amoxicillin-clavulanate (90 mg/kg/day amoxicillin component with 6.4 mg/kg/day clavulanate in 2 divided doses) 1, 2
• Reassess at 72 hours—if no improvement, consider complications or referral 1, 2

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Essential Adjunctive Therapies

Intranasal corticosteroids, saline nasal irrigation, and analgesics should be offered to all patients to improve symptom resolution and reduce inflammation. 3, 1

Strongly Recommended

• Intranasal corticosteroids (mometasone, fluticasone, or budesonide twice daily): Reduce mucosal inflammation with minimal systemic absorption—number needed to treat is 14 for modest symptom improvement 3, 1
• Saline nasal irrigation (physiologic or hypertonic saline): Provides symptomatic relief and removes mucus 3, 1
• Analgesics (acetaminophen or ibuprofen): Relieve facial pain and fever 3, 1

May Consider

• Oral decongestants (pseudoephedrine): Provide symptomatic relief, but avoid in hypertension or anxiety 3
• Topical decongestants (oxymetazoline): Limit use to 3-5 days maximum to avoid rebound congestion and rhinitis medicamentosa 3, 5

Avoid or Use Cautiously

• Oral antihistamines: No clinical studies support use in acute sinusitis unless concomitant allergic rhinitis is present 3
• Short-term oral corticosteroids: May be reasonable for patients with marked mucosal edema or treatment failure, but should not replace antibiotics when bacterial infection is suspected 3, 2

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Critical Pitfalls to Avoid

• Do not prescribe antibiotics for symptoms <10 days unless severe features are present (fever ≥39°C with purulent discharge for ≥3 consecutive days) 1, 2
• 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 1, 2
• Do not use azithromycin or macrolides as first-line therapy due to 20-25% resistance rates 1, 2, 6
• Reassess at 3-5 days—waiting beyond 7 days to change therapy in non-responders delays effective treatment and may allow complications 1, 2
• Complete the full antibiotic course even after symptoms improve to prevent relapse 1, 2

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When to Refer to a Specialist

Refer to otolaryngology if symptoms are refractory to two courses of appropriate antibiotics, recurrent sinusitis (≥3 episodes per year), or suspected complications. 1, 2

Indications for Referral

• No improvement after 7 days of appropriate second-line antibiotic therapy 1, 2
• Worsening symptoms at any time despite treatment 1, 2
• Suspected complications: orbital cellulitis, meningitis, brain abscess 1, 2
• Recurrent sinusitis requiring evaluation for allergic rhinitis, immunodeficiency, or anatomic abnormalities 1, 2