What is the appropriate management of acute sinusitis in an otherwise healthy adult?

Acute Sinusitis Treatment in Otherwise Healthy Adults

For an otherwise healthy adult with acute sinusitis, the first critical step is determining whether antibiotics are even indicated—most cases are viral and resolve spontaneously within 7–10 days without antimicrobial therapy. 1

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Step 1: Confirm Bacterial Sinusitis Before Prescribing Antibiotics

Antibiotics should only be prescribed when acute bacterial rhinosinusitis (ABRS) is confirmed by meeting at least one of three clinical patterns:

• Persistent symptoms ≥10 days without improvement: purulent nasal discharge plus either nasal obstruction/congestion or facial pain/pressure/fullness. 1
• Severe symptoms ≥3–4 consecutive days: fever ≥39°C (102.2°F) with purulent nasal discharge and facial pain. 1
• "Double sickening": initial improvement from a viral upper respiratory infection followed by new-onset fever, worsening nasal discharge, or markedly increased cough within 10 days. 1

Critical pitfall: Approximately 98–99.5% of acute rhinosinusitis cases are viral and resolve spontaneously within 7–10 days; do not prescribe antibiotics for symptoms <10 days unless the severe criteria above are met. 1

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Step 2: First-Line Antibiotic Therapy (No Penicillin Allergy)

Amoxicillin-clavulanate 875 mg/125 mg orally twice daily for 5–10 days is the preferred first-line regimen, providing 90–92% predicted clinical efficacy against Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis. 1 The clavulanate component is essential because 30–40% of H. influenzae and 90–100% of M. catarrhalis produce β-lactamase. 1

Treatment duration: Continue for 5–10 days or until the patient is symptom-free for 7 consecutive 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 (2 g/125 mg twice daily) is indicated when any of the following risk factors are present: recent antibiotic use (≤4–6 weeks), age >65 years, daycare exposure, moderate-to-severe symptoms, comorbidities (diabetes, chronic cardiac/hepatic/renal disease), or immunocompromised state. 1

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Step 3: Alternatives for Penicillin-Allergic Patients

Non-Severe (Non-Type I) Penicillin Allergy

Use a second- or third-generation cephalosporin for 10 days (e.g., cefuroxime-axetil, cefpodoxime-proxetil, cefdinir, or cefprozil); cross-reactivity with penicillins is negligible (<1%). 1

Severe (Type I/Anaphylactic) Penicillin Allergy

Respiratory fluoroquinolones are the treatment of choice:

• Levofloxacin 500 mg once daily for 10–14 days 1
• Moxifloxacin 400 mg once daily for 10 days 1

Both achieve 90–92% predicted efficacy against multidrug-resistant S. pneumoniae and β-lactamase-producing organisms. 1

Reserve fluoroquinolones for severe penicillin allergy or documented treatment failure to limit resistance development; they should not be used as routine first-line therapy. 1

Suboptimal Alternative

Doxycycline 100 mg once daily for 10 days yields only 77–81% predicted efficacy with a 20–25% bacteriologic failure rate due to limited H. influenzae coverage. 1 Use only when cephalosporins and fluoroquinolones are contraindicated. Contraindicated in children <8 years due to tooth enamel discoloration. 1

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Step 4: Essential Adjunctive Therapies (Add to All Patients)

Intranasal corticosteroids (mometasone, fluticasone, or budesonide) twice daily significantly reduce mucosal inflammation and accelerate symptom resolution; this recommendation is supported by strong evidence from multiple randomized controlled trials. 1

Saline nasal irrigation 2–3 times daily provides symptomatic relief and enhances mucus clearance. 1

Analgesics (acetaminophen or ibuprofen) are recommended for pain and fever control. 1

Decongestants (oral or topical) may be used, but limit topical agents to ≤3 days to avoid rebound congestion. 1

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Step 5: Watchful Waiting Strategy (Alternative to Immediate Antibiotics)

For adults with uncomplicated ABRS and reliable follow-up, initial observation without antibiotics is appropriate. 1 Antibiotics are started only if no improvement by day 7 or if symptoms worsen at any time. 1

Number needed to treat (NNT) with antibiotics is 10–15 to achieve one additional cure compared with placebo, reflecting the high rate of spontaneous recovery. 1

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Step 6: Monitoring and Reassessment

Early Reassessment (Days 3–5)

If no clinical improvement (persistent purulent drainage, unchanged facial pain, or worsening), switch to high-dose amoxicillin-clavulanate 2 g/125 mg twice daily or a respiratory fluoroquinolone (levofloxacin or moxifloxacin). 1

Day 7 Reassessment

Persistent or worsening symptoms require:

1. Confirmation of ABRS diagnosis
2. Exclusion of complications (orbital cellulitis, meningitis, intracranial abscess)
3. Imaging (CT) only if complications are suspected
4. Referral to otolaryngology 1

Expected timeline of recovery: Noticeable improvement should occur within 3–5 days of appropriate therapy, with complete resolution by 10–14 days or when symptom-free for 7 consecutive days. 1

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Step 7: Antibiotics to Avoid in ABRS

Macrolides (azithromycin, clarithromycin): 20–25% resistance rates in S. pneumoniae and H. influenzae make them unsuitable. 1

Trimethoprim-sulfamethoxazole: ≈50% resistance in S. pneumoniae and ≈27% in H. influenzae. 1

First-generation cephalosporins (e.g., cephalexin): Inadequate because ≈50% of H. influenzae strains produce β-lactamase. 1

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Step 8: Referral to Otolaryngology

Immediate referral is indicated for any of the following:

• No improvement after 7 days of appropriate second-line antibiotic therapy 1
• Worsening symptoms at any point during treatment 1
• Suspected complications (severe headache, visual changes, periorbital swelling/erythema, proptosis, diplopia, altered mental status, cranial nerve deficits) 1
• Recurrent sinusitis (≥3 episodes per year) requiring evaluation for underlying allergic rhinitis, immunodeficiency, or anatomic abnormalities 1

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Common Pitfalls and Safety Considerations

Do not prescribe antibiotics for symptoms <10 days unless severe features (fever ≥39°C with purulent discharge for ≥3 consecutive days) are present. 1

Avoid routine imaging (X-ray or CT) for uncomplicated ABRS; up to 87% of viral upper-respiratory infections show sinus abnormalities on imaging, leading to unnecessary interventions. 1

Ensure adequate treatment duration (≥5 days for adults, ≥10 days for children) to prevent relapse. 1

Gastrointestinal adverse effects with amoxicillin-clavulanate are common: diarrhea occurs in 40–43% of patients, with severe diarrhea in 7–8%. 1