Antibiotic Selection for Acute Bacterial Sinusitis with Penicillin Allergy
For an adult with acute bacterial sinusitis and documented penicillin allergy, prescribe a second‑ or third‑generation cephalosporin (cefuroxime, cefpodoxime, or cefdinir) for 10 days as first‑line therapy if the allergy is non‑severe; reserve respiratory fluoroquinolones (levofloxacin or moxifloxacin) only for patients with severe (Type I/anaphylactic) penicillin allergy. 12
Step 1: Classify the Penicillin Allergy Type
Non‑severe (non‑Type I) allergy includes mild rash, delayed‑onset reactions, or gastrointestinal intolerance—these patients can safely receive cephalosporins because cross‑reactivity is negligible (essentially zero risk with second‑ and third‑generation agents). 12
Severe (Type I/anaphylactic) allergy includes anaphylaxis, urticaria, angioedema, or bronchospasm occurring within minutes to hours of penicillin exposure—these patients require fluoroquinolones because cephalosporins carry a 1–10 % cross‑reactivity risk. 12
Step 2: Confirm the Diagnosis of Acute Bacterial Rhinosinusitis
Antibiotics are indicated only when the patient meets at least one of the following criteria:
Persistent symptoms ≥10 days without improvement (purulent nasal discharge plus nasal obstruction or facial pain/pressure). 13
Severe symptoms ≥3–4 consecutive days with fever ≥39 °C, purulent nasal discharge, and facial pain. 13
"Double sickening"—initial improvement from a viral URI followed by worsening symptoms within 10 days. 13
Do not prescribe antibiotics for symptoms <10 days unless the severe criteria above are met, because 98–99.5 % of acute rhinosinusitis is viral and resolves spontaneously within 7–10 days. 13
Step 3: Select the Appropriate Antibiotic Based on Allergy Type
For Non‑Severe Penicillin Allergy (First‑Line)
Prescribe a second‑ or third‑generation cephalosporin for 10 days:
Cefuroxime‑axetil 250–500 mg orally twice daily for 10 days. 12
Cefpodoxime‑proxetil 200 mg orally twice daily for 10 days. 12
Rationale: These agents provide 83–88 % predicted clinical efficacy against Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis, with essentially zero cross‑reactivity risk in non‑severe penicillin allergy. 14
For Severe (Type I/Anaphylactic) Penicillin Allergy (First‑Line)
Prescribe a respiratory fluoroquinolone:
Rationale: Fluoroquinolones provide 90–92 % predicted clinical efficacy against all major sinusitis pathogens, including multidrug‑resistant S. pneumoniae and β‑lactamase‑producing H. influenzae and M. catarrhalis, with no cross‑reactivity to penicillins. 14
Suboptimal Alternative (Use Only When Fluoroquinolones Are Contraindicated)
- Doxycycline 100 mg orally once daily for 10 days yields only 77–81 % predicted efficacy with a 20–25 % bacteriologic failure rate due to limited activity against H. influenzae; reserve this option only when fluoroquinolones are contraindicated (e.g., pregnancy, tendon disorders, QT‑prolongation risk). 14
Step 4: Add Essential Adjunctive Therapies to All Patients
Intranasal corticosteroids (mometasone, fluticasone, or budesonide) twice daily reduce mucosal inflammation and accelerate symptom resolution—supported by strong evidence from multiple randomized controlled trials. 13
Saline nasal irrigation 2–3 times daily provides symptomatic relief and helps clear purulent secretions. 13
Analgesics (acetaminophen or ibuprofen) for pain and fever control. 13
Step 5: Monitor and Reassess for Treatment Failure
Reassess at 3–5 days: If no clinical improvement (persistent purulent drainage, unchanged facial pain, or worsening), switch to a respiratory fluoroquinolone (if not already prescribed) or escalate to high‑dose amoxicillin‑clavulanate if the allergy permits. 13
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. 13
Urgent evaluation is required at any time for worsening pain/fever, severe headache, visual changes, periorbital swelling, or altered mental status. 13
Critical Pitfalls to Avoid
Do not use macrolides (azithromycin, clarithromycin) because resistance exceeds 20–25 % for both S. pneumoniae and H. influenzae, making treatment failure likely. 156
Do not use trimethoprim‑sulfamethoxazole due to ~50 % resistance in S. pneumoniae and 27 % resistance in H. influenzae. 1
Do not use first‑generation cephalosporins (cephalexin, cefadroxil) because they lack adequate coverage against β‑lactamase‑producing H. influenzae (~50 % of strains). 17
Reserve fluoroquinolones appropriately: Use them only for severe penicillin allergy or treatment failures—not as routine first‑line therapy in non‑allergic patients—to limit resistance development. 14
Ensure adequate treatment duration (minimum 10 days for cephalosporins, 10–14 days for fluoroquinolones) to prevent relapse and resistance. 15
When to Refer to Otolaryngology
No improvement after 7 days of appropriate second‑line antibiotic therapy. 1
Worsening symptoms at any point during treatment. 1
Suspected complications (orbital cellulitis, meningitis, severe headache, visual changes, periorbital swelling, altered mental status). 1
Recurrent sinusitis (≥3 episodes per year) requiring evaluation for underlying allergic rhinitis, immunodeficiency, or anatomic abnormalities. 1