Treatment Plan for Sinus Infection
Distinguish Viral from Bacterial Sinusitis First
Most sinus infections are viral and do not require antibiotics. Approximately 98–99.5% of acute rhinosinusitis cases are viral and resolve spontaneously within 7–10 days without antibiotics. 1, 2
Prescribe antibiotics only when acute bacterial rhinosinusitis (ABRS) is confirmed by one of three patterns:
- Persistent symptoms ≥10 days without improvement—purulent nasal discharge plus either nasal obstruction or facial pain/pressure/fullness. 1, 2
- Severe symptoms ≥3–4 consecutive days—fever ≥39°C (102.2°F) with purulent nasal discharge and facial pain. 1, 2
- "Double sickening"—initial improvement from a viral upper respiratory infection followed by worsening symptoms within 10 days. 1, 2, 3
Do not prescribe antibiotics for symptoms lasting <10 days unless the severe criteria above are met. 1, 2
First-Line Antibiotic Therapy
Amoxicillin-clavulanate 875 mg/125 mg orally twice daily for 5–10 days is the preferred first-line regimen for adults with confirmed ABRS. This provides 90–92% predicted clinical efficacy against the three major pathogens: Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis. 1, 2, 4 The clavulanate component is essential because 30–40% of H. influenzae and 90–100% of M. catarrhalis produce β-lactamase enzymes that inactivate amoxicillin alone. 1, 4
Treatment duration: Continue for 5–10 days or until symptom-free for 7 consecutive days (typically 10–14 days total). 1, 2 Recent evidence supports shorter 5–7 day courses with comparable efficacy and fewer adverse effects. 1, 2
High-dose amoxicillin-clavulanate (2 g/125 mg twice daily) is indicated when any of the following risk factors are present:
- Recent antibiotic use within the past 4–6 weeks 1, 2
- Age >65 years 1, 2
- Daycare attendance or close contact with daycare children 1, 2
- Moderate-to-severe symptoms 1, 2
- Comorbidities (diabetes, chronic cardiac/hepatic/renal disease) 1, 2
- Immunocompromised state 1, 2
Alternatives for Penicillin Allergy
Non-Severe (Non-Type I) Penicillin Allergy
Use a second- or third-generation cephalosporin for 10 days. Cross-reactivity with penicillins is negligible (<1%). 1, 2 Options include:
Severe (Type I/Anaphylactic) Penicillin Allergy
Use a respiratory fluoroquinolone:
Both achieve 90–92% predicted efficacy against multidrug-resistant S. pneumoniae and β-lactamase-producing organisms. 1, 2 Reserve fluoroquinolones for severe penicillin allergy or documented treatment failure to limit resistance development. 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. 1, 2 Use only when cephalosporins and fluoroquinolones are contraindicated. Contraindicated in children <8 years due to tooth enamel discoloration. 1, 2
Antibiotics to Avoid
Never use the following as first-line therapy:
- Macrolides (azithromycin, clarithromycin)—20–25% resistance rates in S. pneumoniae and H. influenzae. 1, 2
- Trimethoprim-sulfamethoxazole—≈50% resistance in S. pneumoniae and ≈27% in H. influenzae. 1, 2
- First-generation cephalosporins (cephalexin)—inadequate coverage because ≈50% of H. influenzae strains produce β-lactamase. 1, 2
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, 2, 5
Saline nasal irrigation 2–3 times daily provides symptomatic relief and enhances mucus clearance. 1, 2, 5
Analgesics (acetaminophen or ibuprofen) for pain and fever control. 1, 2, 5
Decongestants (oral or topical) may be used; limit topical agents to ≤3 days to avoid rebound congestion. 1, 2
Watchful Waiting Strategy
For adults with uncomplicated ABRS and reliable follow-up, initial observation without antibiotics is appropriate. Start antibiotics only if there is no improvement by day 7 or if symptoms worsen at any time. 1, 2, 5 The number needed to treat (NNT) with antibiotics is 10–15 to achieve one additional cure compared with placebo, reflecting the high spontaneous recovery rate. 1, 2
Monitoring and Reassessment
Reassess at 3–5 days: If there is 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, 2
Reassess at 7 days: Persistent or worsening symptoms require:
- Confirmation of ABRS diagnosis 1, 2
- Exclusion of complications (orbital cellulitis, meningitis, intracranial abscess) 1, 2
- Imaging (CT) only if complications are suspected 1, 2, 5
- Referral to otolaryngology 1, 2, 5
Expected timeline: 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, 2
Referral to Otolaryngology
Refer immediately for any of the following:
- No improvement after 7 days of appropriate second-line antibiotic therapy 1, 2, 5
- Worsening symptoms at any point during treatment 1, 2, 5
- Suspected complications (severe headache, visual changes, periorbital swelling/erythema, proptosis, diplopia, altered mental status, cranial nerve deficits) 1, 2, 5
- Recurrent sinusitis (≥3 episodes per year) requiring evaluation for underlying allergic rhinitis, immunodeficiency, or anatomic abnormalities 1, 2, 6, 5
Management of Recurrent Acute Sinusitis
For patients with recurrent acute sinusitis (≥3 episodes per year), use the same 10–14 day antibiotic course as for first-episode ABRS. 6 However, only 40% of patients with recurrent rhinosinusitis show improvement with standard 10-day amoxicillin therapy, suggesting recurrent disease may be more resistant. 6
After completing treatment, evaluate for underlying causes:
- Allergic rhinitis 6, 5
- Immunodeficiency 6, 5
- Anatomic abnormalities 6, 5
- Gastroesophageal reflux disease 6
Consider referral to an allergist-immunologist or otolaryngologist for comprehensive evaluation. 6, 5
Chronic Rhinosinusitis (CRS) Management
Distinguish CRS (symptoms >8 weeks) from recurrent acute rhinosinusitis. CRS requires objective evidence of sinonasal inflammation (nasal endoscopy or CT) before diagnosis. 5
CRS management differs fundamentally from acute disease:
- Intranasal corticosteroids are the primary therapy 2, 5
- Daily high-volume saline irrigation 2, 5
- Longer-duration antibiotic therapy for chronic infectious sinusitis 2
- Antibiotics should be reserved for acute exacerbations with documented bacterial infection 2
Evaluate for modifying factors:
- Asthma 5
- Cystic fibrosis 5
- Immunocompromised state 5
- Ciliary dyskinesia 5
- Allergic rhinitis 5
- Anatomic variations (deviated septum, nasal polyps) 5
Antifungal therapy (topical or systemic) is not recommended for CRS. 2
Critical Pitfalls to Avoid
Do not prescribe antibiotics for symptoms <10 days unless severe features (fever ≥39°C with purulent discharge for ≥3 consecutive days) are present. 1, 2
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, 2, 5
Ensure adequate treatment duration (≥5 days for adults, ≥10 days for children) to prevent relapse. 1, 2
Fluoroquinolones should not be used as first-line therapy in patients without documented β-lactam allergy to limit resistance development. 1, 2
Gastrointestinal adverse effects with amoxicillin-clavulanate are common: diarrhea occurs in 40–43% of patients, with severe diarrhea in 7–8%. 1, 2
Do not extend the initial antibiotic course beyond 3–5 days without clinical improvement. Early discontinuation prevents unnecessary drug exposure and bacterial proliferation. 1, 2