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

Treatment of Acute Bacterial Sinusitis

For most patients with acute bacterial sinusitis, amoxicillin-clavulanate 875 mg/125 mg twice daily for 5-10 days is the preferred first-line treatment, with intranasal corticosteroids added as adjunctive therapy to reduce inflammation and accelerate symptom resolution. 1

Confirm the Diagnosis Before Prescribing Antibiotics

Before initiating antibiotic therapy, confirm that bacterial sinusitis is likely by identifying one of three specific clinical patterns 1:

• Persistent symptoms: Nasal congestion, purulent discharge, or facial pain lasting ≥10 days without improvement 1, 2
• Severe symptoms: High fever (≥39°C) with purulent nasal discharge for ≥3 consecutive days 1, 3
• "Double sickening": Initial improvement from viral URI followed by worsening symptoms 1, 2

Critical pitfall: 98-99.5% of acute rhinosinusitis cases are viral and resolve spontaneously within 7-10 days—prescribing antibiotics before 10 days (unless severe symptoms are present) contributes to antimicrobial resistance without clinical benefit 1

First-Line Antibiotic Treatment

Standard Therapy for Most Patients

Amoxicillin-clavulanate 875 mg/125 mg twice daily for 5-10 days provides optimal coverage against the three major pathogens: Streptococcus pneumoniae, β-lactamase-producing Haemophilus influenzae, and Moraxella catarrhalis 1

• The clavulanate component is essential because nearly 50% of H. influenzae strains and 90-100% of M. catarrhalis strains produce β-lactamase, rendering plain amoxicillin ineffective 1
• Treatment duration of 5-7 days has comparable efficacy to 10-14 days with fewer side effects 1, 4
• Continue treatment until symptom-free for 7 days (typically 10-14 days total) 1

High-Dose Therapy for High-Risk Patients

Use high-dose amoxicillin-clavulanate (2 g amoxicillin twice daily) for patients with 1:

• Recent antibiotic use within the past 4-6 weeks
• Age >65 years
• Moderate-to-severe symptoms
• Comorbid conditions or immunocompromised state
• Geographic areas with high prevalence of drug-resistant S. pneumoniae

Treatment for Penicillin-Allergic Patients

Non-Severe Penicillin Allergy (Rash, Delayed Reactions)

Second- or third-generation cephalosporins are safe and preferred because the risk of cross-reactivity is negligible 1:

• Cefuroxime-axetil (second-generation): Standard dosing for 5-10 days 1
• Cefpodoxime-proxetil or cefdinir (third-generation): Superior activity against H. influenzae 1

Severe Penicillin Allergy (Anaphylaxis, Type I Hypersensitivity)

Respiratory fluoroquinolones are the treatment of choice 1:

• Levofloxacin 500 mg once daily for 10-14 days OR
• Moxifloxacin 400 mg once daily for 10 days
• These provide 90-92% predicted clinical efficacy against drug-resistant S. pneumoniae and complete coverage of β-lactamase-producing organisms 1

What NOT to use:

• Azithromycin and macrolides: Resistance rates exceed 20-25% for both S. pneumoniae and H. influenzae—explicitly contraindicated as first-line therapy 1
• Trimethoprim-sulfamethoxazole: 50% resistance rate for S. pneumoniae 1
• First-generation cephalosporins (cephalexin): Inadequate coverage against H. influenzae 1

Essential Adjunctive Therapies

Intranasal Corticosteroids (Strongly Recommended)

Add intranasal corticosteroids (mometasone, fluticasone, or budesonide) twice daily to reduce mucosal inflammation and improve symptom resolution 1, 5:

• Fluticasone propionate: 200 mcg/day (two 50-mcg sprays per nostril once daily) 5
• Maximum effect may take several days, but symptom improvement can occur within 12 hours 5
• Minimal systemic absorption with excellent safety profile 1

Supportive Measures

• Analgesics: Acetaminophen or NSAIDs for pain and fever relief 1
• Saline nasal irrigation: High-volume irrigation helps clear secretions 1
• Adequate hydration and warm facial compresses 1
• Sleep with head elevated to promote drainage 1

Decongestants: May provide symptomatic relief, but topical decongestants should not be used for more than 3 days to avoid rebound congestion 6

When to Switch Antibiotics (Treatment Failure Protocol)

Reassess at 3-5 days: If no improvement occurs, switch to a different antibiotic or re-evaluate the diagnosis 1

Second-Line Options After Amoxicillin-Clavulanate Failure

Switch to a respiratory fluoroquinolone 1:

• Levofloxacin 500 mg once daily for 10-14 days OR
• Moxifloxacin 400 mg once daily for 10 days
• These provide excellent coverage against drug-resistant S. pneumoniae (including multi-drug resistant strains) and β-lactamase-producing organisms 1

Alternative: High-dose amoxicillin-clavulanate (4 g amoxicillin/250 mg clavulanate per day) for enhanced coverage 1

Special Considerations for Recurrent Sinusitis

Recurrent sinusitis is defined as ≥3 episodes per year and requires evaluation for underlying causes 7, 2:

• Allergic rhinitis: Refer to allergist-immunologist for IgE testing to inhalant allergens 7, 2
• Anatomic abnormalities: Refer to otolaryngologist for evaluation of structural obstruction 7, 2
• Immunodeficiency: Consider immune workup if infections are unusually severe or frequent 2

For acute exacerbations in recurrent sinusitis, use high-dose amoxicillin-clavulanate (1.5-4 g/day) for 10-14 days to cover resistant bacteria 7

When to Refer to a Specialist

Refer to otolaryngology or allergist-immunologist when 1, 7:

• Symptoms refractory to two courses of appropriate antibiotics
• Recurrent sinusitis (≥3 episodes per year)
• Suspected complications: orbital cellulitis, meningitis, intracranial extension
• Chronic sinusitis (symptoms ≥8 weeks with abnormal imaging)
• Need for sinus aspiration/culture in immunocompromised patients

Red Flags Requiring Immediate Evaluation

Seek urgent evaluation for 2:

• Orbital complications: periorbital edema, vision changes, ophthalmoplegia
• Neurological complications: severe headache, altered mental status, focal deficits
• High fever with severe headache suggesting intracranial extension

Critical Pitfalls to Avoid

• Do not prescribe antibiotics for viral rhinosinusitis lasting <10 days unless severe symptoms are present 1
• Do not use mucus color alone to determine antibiotic need—purulent discharge reflects neutrophils, not necessarily bacteria 1
• Reserve fluoroquinolones for treatment failures or documented severe allergies—overuse promotes antimicrobial resistance 1
• Complete the full antibiotic course even after symptoms improve to prevent relapse 1
• Never use clindamycin as monotherapy—it lacks activity against H. influenzae and M. catarrhalis 1