What is the recommended management of acute sinusitis in a generally healthy adult?

Management of Acute Sinus Infection in a Generally Healthy Adult

For a generally healthy adult with acute sinusitis, first confirm bacterial infection using clinical criteria (symptoms ≥10 days, severe symptoms ≥3–4 days with high fever, or "double sickening"), then prescribe amoxicillin-clavulanate 875 mg/125 mg twice daily for 5–10 days as first-line therapy, while adding intranasal corticosteroids and saline irrigation to all patients regardless of antibiotic use. 1, 2

Step 1: Distinguish Viral from Bacterial Sinusitis

• Most cases (98–99.5%) of acute rhinosinusitis are viral and resolve spontaneously within 7–10 days without antibiotics. Do not prescribe antibiotics for symptoms lasting <10 days unless severe features are present. 3, 1, 4

• Diagnose acute bacterial rhinosinusitis (ABRS) only when ONE of these three patterns is present:

  • Persistent symptoms ≥10 days without improvement (purulent nasal discharge plus nasal obstruction OR facial pain/pressure/fullness) 3, 1, 4
  • Severe symptoms ≥3–4 consecutive days with fever ≥39°C (102.2°F), purulent nasal discharge, and facial pain 3, 1, 4
  • "Double sickening": initial improvement from a viral URI followed by worsening symptoms within 10 days 3, 1, 4

• Clinical features that increase bacterial likelihood: unilateral maxillary tooth pain or facial pain worsening when bending forward, unilateral sinus tenderness on examination. 5

Step 2: First-Line Antibiotic Therapy (When Bacterial Infection Confirmed)

• 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. 3, 1, 2

• Treatment duration: Continue for 5–10 days OR until symptom-free for 7 consecutive days (typically 10–14 days total). Recent evidence supports shorter 5–7 day courses with comparable efficacy and fewer adverse effects. 1, 2, 6, 7

• Why amoxicillin-clavulanate over plain amoxicillin: The clavulanate component is essential because 30–40% of H. influenzae and 90–100% of M. catarrhalis produce β-lactamase, rendering plain amoxicillin ineffective. 3, 2, 8

Step 3: Alternatives for Penicillin Allergy

Non-Severe (Non-Type I) Penicillin Allergy

• Second- or third-generation cephalosporins for 10 days (cefuroxime-axetil, cefpodoxime-proxetil, cefdinir, or cefprozil); cross-reactivity with penicillins is negligible (<1%). 3, 1, 2

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
  • Both achieve 90–92% predicted efficacy against multidrug-resistant S. pneumoniae and β-lactamase-producing organisms. 3, 1, 2, 9

• Reserve fluoroquinolones for severe penicillin allergy or documented treatment failure to limit resistance development; do not use as routine first-line therapy. 1, 2

Suboptimal Alternative

• Doxycycline 100 mg once daily for 10 days offers lower efficacy (77–81%) with a 20–25% bacteriologic failure rate due to limited H. influenzae coverage; use only when cephalosporins and fluoroquinolones are contraindicated. Contraindicated in children <8 years. 3, 1

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; supported by strong evidence from multiple randomized controlled trials. 3, 1, 2

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

• Analgesics (acetaminophen or ibuprofen) for pain and fever control. 3, 1, 2

• Decongestants (oral or topical) may be used; limit topical agents to ≤3 days to avoid rebound congestion. 3, 10

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

• For uncomplicated ABRS with reliable follow-up, initial observation without antibiotics is appropriate. Start antibiotics only if no improvement by day 7 OR if symptoms worsen at any time. 3, 1, 4

• 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. 3, 1

Step 6: Monitoring and Reassessment

• Reassess at 3–5 days: 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. 3, 1, 2

• Reassess at 7 days: 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 3, 1, 4

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

Step 7: Antibiotics to AVOID

• Macrolides (azithromycin, clarithromycin): 20–25% resistance rates in S. pneumoniae and H. influenzae; explicitly contraindicated by the American Academy of Pediatrics. 3, 1

• Trimethoprim-sulfamethoxazole: ≈50% resistance in S. pneumoniae and ≈27% in H. influenzae. 3, 1

• First-generation cephalosporins (cephalexin): Inadequate coverage because ≈50% of H. influenzae strains produce β-lactamase. 3, 1

Step 8: When to Refer to Otolaryngology

• No improvement after 7 days of appropriate second-line antibiotic therapy 3, 1, 2
• Worsening symptoms at any point during treatment 3, 1, 2
• Suspected complications: severe headache, visual changes, periorbital swelling/erythema, proptosis, diplopia, altered mental status, or cranial nerve deficits 3, 1, 4
• Recurrent sinusitis (≥3 episodes per year) requiring evaluation for underlying allergic rhinitis, immunodeficiency, or anatomic abnormalities 3, 1, 4

Critical Pitfalls to Avoid

• Do not obtain routine imaging (X-ray or CT) for uncomplicated ABRS; up to 87% of viral URIs show sinus abnormalities on imaging, leading to unnecessary interventions. 3, 1, 4

• Do not prescribe antibiotics for symptoms <10 days unless severe features (fever ≥39°C with purulent discharge for ≥3 consecutive days) are present. 3, 1, 5

• Ensure adequate treatment duration (≥5 days for adults) to prevent relapse. 1, 6, 7

• Gastrointestinal adverse effects with amoxicillin-clavulanate are common: diarrhea in 40–43% of patients, severe diarrhea in 7–8%. 3, 1

• Purulent nasal discharge alone does not indicate bacterial infection; it reflects neutrophilic inflammation common to viral disease. 3, 1