What is the recommended management for acute rhinosinusitis in a generally healthy 37‑year‑old adult?

Treatment of Acute Bacterial Sinusitis in a 37-Year-Old Adult

First-Line Antibiotic Therapy

Amoxicillin-clavulanate 875 mg/125 mg twice daily for 5–10 days is the preferred first-line antibiotic for acute bacterial rhinosinusitis in otherwise healthy adults. 1 This regimen provides 90–92% predicted clinical efficacy against the three major pathogens: 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, rendering plain amoxicillin ineffective against these organisms. 1

• Treatment duration: Continue for 5–10 days or until 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

• Plain amoxicillin (500 mg twice daily for mild disease or 875 mg twice daily for moderate disease) may be used only in patients with mild symptoms who have not received antibiotics in the preceding 4–6 weeks. 2, 1 However, amoxicillin-clavulanate is generally preferred given the prevalence of β-lactamase-producing organisms. 1

Diagnostic Criteria Before Prescribing Antibiotics

Antibiotics should only be prescribed when acute bacterial rhinosinusitis is confirmed by at least one of three clinical patterns: 2, 1

1. Persistent symptoms ≥10 days without improvement: purulent nasal discharge plus either nasal obstruction or facial pain/pressure/fullness. 2

2. Severe symptoms ≥3–4 consecutive days: fever ≥39°C (102.2°F) with purulent nasal discharge and facial pain. 2

3. "Double sickening": initial improvement from a viral upper respiratory infection followed by worsening symptoms within 10 days. 2

Critical pitfall: Approximately 98–99.5% of acute rhinosinusitis cases are viral and resolve spontaneously within 7–10 days without antibiotics. 1 Do not prescribe antibiotics for symptoms lasting <10 days unless severe features (fever ≥39°C with purulent discharge for ≥3 consecutive days) are present. 2, 1

Watchful Waiting as an Alternative Strategy

For uncomplicated acute bacterial rhinosinusitis with reliable follow-up, initial observation without antibiotics is an appropriate strategy. 2, 3 Initiate antibiotics only if there is no improvement by day 7 or if symptoms worsen at any time. 2, 3 The 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. 2

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. 2, 1, 4

• Saline nasal irrigation 2–3 times daily provides symptomatic relief and helps clear purulent secretions. 2, 1, 5

• Analgesics (acetaminophen or ibuprofen) for pain and fever control. 2, 4

Alternatives for Penicillin Allergy

• Non-severe (non-Type I) penicillin allergy: Use a second- or third-generation cephalosporin (cefuroxime-axetil, cefpodoxime-proxetil, cefdinir, or cefprozil) for 10 days. Cross-reactivity with penicillins is negligible (<1%). 1

• Severe (Type I/anaphylactic) penicillin allergy: Use a respiratory fluoroquinolone—levofloxacin 500 mg once daily for 10–14 days or moxifloxacin 400 mg once daily for 10 days—both achieving 90–92% predicted efficacy against multidrug-resistant S. pneumoniae and β-lactamase-producing organisms. 1

• Doxycycline 100 mg once daily for 10 days is an acceptable but suboptimal alternative (predicted efficacy 77–81% with a 20–25% bacteriologic failure rate) due to limited H. influenzae coverage. 1, 5 Reserve only when fluoroquinolones and cephalosporins are contraindicated.

Monitoring and Reassessment Protocol

• 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. 2, 1

• Reassess at 7 days: Persistent or worsening symptoms warrant confirmation of diagnosis, exclusion of complications (orbital cellulitis, meningitis, intracranial abscess), and consideration of imaging or ENT referral. 2, 1

• Expected timeline: Noticeable improvement should occur within 3–5 days of appropriate therapy, with complete resolution by 10–14 days. 1

Antibiotics to Avoid

• Macrolides (azithromycin, clarithromycin): Resistance rates are 20–25% for both S. pneumoniae and H. influenzae. 1

• Trimethoprim-sulfamethoxazole: Resistance is approximately 50% in S. pneumoniae and 27% in H. influenzae. 1, 5

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

Referral to Otolaryngology

Refer immediately if any of the following occur: 2, 1

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

Common Pitfalls

• Imaging is not recommended for uncomplicated acute rhinosinusitis; up to 87% of viral upper respiratory infections show sinus abnormalities on imaging, leading to unnecessary interventions. 2, 6

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

• Ensure a minimum treatment duration of 5 days for adults to prevent relapse. 1