What is the recommended treatment for a patient with a sinus infection, considering their medical history and allergy status?

Treatment of Sinus Infection

First-Line Antibiotic Treatment

For acute bacterial sinusitis, amoxicillin-clavulanate 875 mg/125 mg twice daily for 5-10 days is the preferred first-line antibiotic, providing superior coverage against β-lactamase-producing organisms that commonly cause treatment failure. 1

• Plain amoxicillin 500 mg twice daily (mild disease) or 875 mg twice daily (moderate disease) remains acceptable for uncomplicated cases without recent antibiotic exposure 1
• High-dose amoxicillin-clavulanate (2 g amoxicillin/125 mg clavulanate twice daily) should be used for patients with recent antibiotic use within the past month, age >65 years, moderate-to-severe symptoms, comorbid conditions, or immunocompromised state 1
• Treatment duration is 5-10 days, with most guidelines recommending treatment until symptom-free for 7 days (typically 10-14 days total) 1

Confirm Bacterial Diagnosis Before Prescribing Antibiotics

Do not prescribe antibiotics for symptoms lasting less than 10 days unless severe symptoms are present—98-99.5% of acute rhinosinusitis is viral and resolves spontaneously within 7-10 days. 1

Bacterial sinusitis should only be diagnosed when symptoms meet one of three criteria: 1

• Persistent symptoms: ≥10 days without improvement
• Severe symptoms: Fever ≥39°C with purulent nasal discharge for ≥3 consecutive days
• "Double sickening": Worsening after initial improvement from a viral upper respiratory infection

Treatment for Penicillin-Allergic Patients

For patients with documented penicillin allergy, the approach depends on allergy type: 1

• Non-severe (non-Type I) allergy (rash, mild reactions): Second-generation cephalosporins (cefuroxime-axetil) or third-generation cephalosporins (cefpodoxime-proxetil, cefdinir, cefprozil) are safe and effective 1
• Severe Type I allergy (anaphylaxis): Respiratory fluoroquinolones (levofloxacin 500 mg once daily or moxifloxacin 400 mg once daily for 10 days) provide 90-92% predicted clinical efficacy 1
• Alternative for mild allergy: Doxycycline 100 mg once daily for 10 days, though it has a 20-25% predicted bacteriologic failure rate 1

Never use azithromycin or other macrolides as first-line therapy—resistance rates exceed 20-25% for both S. pneumoniae and H. influenzae. 1

When to Switch Antibiotics (Treatment Failure Protocol)

Reassess patients at specific timepoints: 1

• At 3-5 days: If no improvement, switch to high-dose amoxicillin-clavulanate (if not already used) or a respiratory fluoroquinolone 1
• At 7 days: Reconfirm diagnosis if symptoms persist or worsen; consider complications, alternative diagnosis, or referral to otolaryngology 1

For treatment failure after initial amoxicillin-clavulanate: 1

• Switch to respiratory fluoroquinolone (levofloxacin 500 mg once daily or moxifloxacin 400 mg once daily for 10 days) 1
• Alternative: Third-generation cephalosporins (cefpodoxime or cefdinir) offer superior activity against H. influenzae 1

Essential Adjunctive Therapies

Intranasal corticosteroids should be added to antibiotic therapy in both acute and chronic sinusitis—they reduce mucosal inflammation and improve symptom resolution with strong evidence from multiple RCTs. 1

• Mometasone, fluticasone, or budesonide twice daily 1
• Fluticasone propionate 200 mcg once daily (two 50-mcg sprays in each nostril) or 100 mcg twice daily (one 50-mcg spray in each nostril) 2
• Maximum effect may take several days; some symptom relief occurs as soon as 12 hours after treatment 2

Additional supportive measures: 1

• Saline nasal irrigation for symptomatic relief and mucus removal
• Analgesics (acetaminophen, NSAIDs) for pain and fever
• Adequate hydration
• Warm facial compresses
• Sleeping with head elevated

Short-Term Oral Corticosteroids (Adjunctive Use Only)

Oral corticosteroids may be considered for short-term use (typically 5 days) in specific situations: 1

• Patients who fail to respond to initial antibiotic treatment
• Marked mucosal edema
• Acute hyperalgic sinusitis (severe pain)

Never give systemic corticosteroids without antibiotics when bacterial sinusitis is suspected—this may suppress the immune response and allow bacterial proliferation. 1

Special Considerations for Allergic Rhinitis

For patients with underlying allergic rhinitis contributing to recurrent sinusitis: 3, 1

• Perform specific IgE (skin or blood) allergy testing when diagnosis is uncertain or when knowledge of specific causative allergen is needed 3
• Consider antihistamines: oral second-generation/less sedating antihistamines for sneezing and itching 3
• Advise avoidance of known allergens or environmental controls (removal of pets, air filtration systems, bed covers, acaricides) 3
• Offer immunotherapy (sublingual or subcutaneous) for patients with inadequate response to pharmacologic therapy 3

Chronic Sinusitis Management (Symptoms >8 Weeks)

Chronic sinusitis requires fundamentally different management than acute disease—initiate daily high-volume saline irrigation combined with intranasal corticosteroids as first-line therapy. 4

For chronic infectious sinusitis with neutrophilic inflammation: 4

• Prolonged antibiotic therapy (21-28 days) with high-dose amoxicillin-clavulanate, cefuroxime, or cefpodoxime
• Add anaerobic coverage with clindamycin or metronidazole if necessary

For chronic hyperplastic eosinophilic sinusitis (associated with nasal polyps, asthma, aspirin sensitivity): 4

• Does not respond to antibiotics
• Requires systemic corticosteroids (oral prednisolone for 1-3 weeks)

Recurrent Sinusitis (≥3 Episodes Per Year)

Recurrent sinusitis requires thorough evaluation of underlying causes—evaluate for allergic rhinitis, immunodeficiency, and anatomic abnormalities. 5

Treatment approach: 5

• High-dose amoxicillin-clavulanate (1.5-4 g/day divided doses) for 10-14 days as first-line treatment
• Intranasal corticosteroids to reduce inflammation and improve sinus drainage
• Consider prophylactic intranasal corticosteroids during high-risk seasons
• Refer to allergist-immunologist for evaluation of allergic factors and immunodeficiency
• Refer to otolaryngologist for evaluation of structural abnormalities

When to Refer to a Specialist

Refer to otolaryngology or allergist-immunology when: 1, 4

• No improvement after 7 days of appropriate second-line therapy
• Symptoms refractory to two courses of appropriate antibiotics
• Recurrent sinusitis (≥3 episodes per year)
• Suspected complications (orbital cellulitis, meningitis, brain abscess)
• Structural abnormalities or obstructing nasal polyps on imaging
• Need for evaluation of underlying allergic factors or immunodeficiency

Critical Pitfalls to Avoid

• Do not use first-generation cephalosporins (cephalexin) for sinusitis—they have inadequate coverage against H. influenzae, with nearly 50% of strains being β-lactamase producing 1
• Do not use fluoroquinolones as routine first-line therapy in patients without documented β-lactam allergies—reserve them for treatment failures or severe allergies to prevent resistance 1
• Do not use clindamycin as monotherapy—it lacks activity against H. influenzae and M. catarrhalis and will fail in 30-40% of cases 1
• Do not use trimethoprim-sulfamethoxazole—resistance rates are 50% for S. pneumoniae and 27% for H. influenzae 1
• Do not prescribe antibiotics for viral rhinosinusitis lasting <10 days—this contributes to antimicrobial resistance without clinical benefit 1