How should acute and chronic sinusitis be managed, including symptomatic therapy, indications for antibiotics, and alternative regimens for penicillin‑allergic patients?

Treatment of Sinusitis

Diagnosis: Distinguish Viral from Bacterial Disease First

Most acute sinusitis (98–99.5%) is viral and resolves spontaneously within 7–10 days without antibiotics; reserve antibiotics only for confirmed bacterial infection. 1

Diagnose acute bacterial rhinosinusitis (ABRS) when ANY ONE of the following is present:

• Persistent symptoms ≥10 days without improvement (purulent nasal discharge plus nasal obstruction or facial pain/pressure/fullness) 1, 2
• Severe symptoms ≥3–4 consecutive days with fever ≥39°C, purulent nasal discharge, and facial pain 1, 2
• "Double sickening": initial improvement from a viral URI followed by worsening within 10 days 1, 2

Do NOT prescribe antibiotics for symptoms <10 days unless the severe criteria above are met. 1, 2

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First-Line Antibiotic Therapy

Standard Adult Regimen

Amoxicillin-clavulanate 875 mg/125 mg orally twice daily for 5–10 days is the preferred first-line antibiotic, providing 90–92% predicted clinical efficacy against Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis. 1, 2

• The clavulanate component is essential because 30–40% of H. influenzae and 90–100% of Moraxella catarrhalis produce β-lactamase 1, 3
• Treatment duration: 5–10 days OR until symptom-free for 7 consecutive days (typically 10–14 days total) 1, 2
• Shorter 5–7 day courses provide comparable efficacy with fewer adverse effects 1

High-Dose Regimen (for Specific Risk Factors)

Use high-dose amoxicillin-clavulanate 2 g/125 mg twice daily when ANY of the following are present:

• Recent antibiotic use (within past 4–6 weeks) 1
• Age >65 years 1
• Daycare attendance or exposure 1
• Moderate-to-severe symptoms 1
• Comorbidities (diabetes, chronic cardiac/hepatic/renal disease) 1
• Immunocompromised state 1

Pediatric Dosing

• Standard-dose amoxicillin: 45 mg/kg/day divided twice daily 1, 2
• High-dose amoxicillin: 80–90 mg/kg/day divided twice daily for children <2 years, daycare attendance, or recent antibiotic use 1, 2
• High-dose amoxicillin-clavulanate: 80–90 mg/kg/day (amoxicillin component) plus 6.4 mg/kg/day clavulanate divided twice daily 1, 2
• Duration: Minimum 10–14 days (longer than adult courses) 1, 2
• Reassess at 72 hours; if no improvement, switch to high-dose amoxicillin-clavulanate 1, 2

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Alternatives for Penicillin Allergy

Non-Severe (Non-Type I) Penicillin Allergy

Use second- or third-generation cephalosporins for 10 days; cross-reactivity with penicillin is negligible:

• Cefuroxime-axetil 1, 2
• Cefpodoxime-proxetil 1, 2
• Cefdinir 1, 2
• Cefprozil 1, 2

Severe (Type I/Anaphylactic) Penicillin Allergy

Use respiratory fluoroquinolones, which provide 90–92% predicted efficacy against multidrug-resistant pathogens:

• Levofloxacin 500 mg once daily for 10–14 days 1, 2
• Moxifloxacin 400 mg once daily for 10 days 1, 2

Suboptimal Alternative (When Fluoroquinolones Contraindicated)

• 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

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Antibiotics to AVOID

Never use the following as first-line therapy:

• Macrolides (azithromycin, clarithromycin): 20–25% resistance rates for S. pneumoniae and H. influenzae 1, 2
• Trimethoprim-sulfamethoxazole: 50% resistance in S. pneumoniae, 27% in H. influenzae 1
• First-generation cephalosporins (cephalexin): inadequate coverage because ~50% of H. influenzae produce β-lactamase 1
• Clindamycin as monotherapy: lacks activity against H. influenzae and M. catarrhalis 1, 4

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Essential Adjunctive Therapies (Add to ALL Patients)

These therapies significantly improve outcomes and should be prescribed for every patient with sinusitis:

• Intranasal corticosteroids (mometasone, fluticasone, or budesonide) twice daily reduce mucosal inflammation and accelerate symptom resolution; supported by strong evidence from multiple randomized controlled trials 5, 1, 4, 2
• Saline nasal irrigation 2–3 times daily provides symptomatic relief and aids mucus clearance 1, 4, 2, 6
• Analgesics (acetaminophen or ibuprofen) for pain and fever control 1, 4, 2
• Decongestants (oral or topical); limit topical agents to ≤3 days to avoid rebound congestion 1, 7

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Monitoring and Reassessment Protocol

Early Reassessment (Days 3–5)

If no clinical improvement (persistent purulent drainage, unchanged facial pain, or worsening), immediately switch to second-line therapy:

• High-dose amoxicillin-clavulanate (if not already used) 1, 2
• Respiratory fluoroquinolone (levofloxacin 500 mg daily or moxifloxacin 400 mg daily) 1, 2

Do NOT extend initial therapy beyond 3–5 days without improvement; early discontinuation prevents unnecessary exposure and bacterial proliferation. 1

Day 7 Reassessment

Persistent or worsening symptoms warrant:

• Confirmation of diagnosis 1, 2
• Exclusion of complications (orbital cellulitis, meningitis, intracranial abscess) 1, 4, 2
• Consideration of imaging (CT) only when complications are suspected 1
• ENT referral 1, 4, 2

Expected Timeline of Recovery

• Noticeable improvement within 3–5 days of appropriate antibiotic therapy 1
• Complete resolution by 10–14 days or when symptom-free for 7 consecutive days 1, 2
• Only 30–41% of patients improve by days 3–5; zero improvement at this stage indicates treatment failure 1

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Watchful Waiting Option

For uncomplicated ABRS with reliable follow-up, initial observation without antibiotics is appropriate:

• Initiate antibiotics only if no improvement by day 7 or if symptoms worsen at any time 1, 2
• The number needed to treat (NNT) with antibiotics is 10–15 to achieve one additional cure 1
• Provide symptomatic treatment (intranasal corticosteroids, saline irrigation, analgesics) during observation 1

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Referral to Otolaryngology

Refer immediately if ANY of the following occur:

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

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Special Populations

Tracheostomy-Dependent Patients

Use high-dose amoxicillin-clavulanate 875 mg/125 mg twice daily for 10–14 days as first-line therapy due to increased risk of resistant organisms and serious complications. 4

• If no improvement at 72 hours, switch to respiratory fluoroquinolone 4
• Closer monitoring required due to higher complication risk 4
• Consider sinus cultures via antral puncture or endoscopy if initial therapy fails 4

Renal Impairment (Hemodialysis)

For ESRD patients on hemodialysis, prescribe amoxicillin-clavulanate 875 mg/125 mg once daily immediately after each dialysis session (typically three times per week). 1

• Always administer antibiotics immediately after dialysis; dosing before dialysis results in drug removal and sub-therapeutic levels 1
• Do NOT use standard twice-daily dosing in ESRD; it leads to drug accumulation and toxicity 1

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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 1
• Do NOT prescribe antibiotics based solely on purulent nasal discharge; it reflects neutrophilic inflammation common to viral disease 1
• Do NOT use fluoroquinolones as routine first-line therapy in patients without documented β-lactam allergy to prevent resistance 1, 2
• Ensure minimum treatment duration (≥5 days for adults, ≥10 days for children) to prevent relapse 1, 2
• Gastrointestinal adverse effects with amoxicillin-clavulanate are common (diarrhea in 40–43% of patients; severe diarrhea in 7–8%) 1