What is the recommended treatment for a patient with acute bacterial sinusitis, considering their past medical history, allergy history, and demographic information, such as age and underlying health conditions?

Treatment of Acute Bacterial Sinusitis

For adults with acute bacterial sinusitis, amoxicillin-clavulanate 875 mg/125 mg twice daily for 5-10 days is the preferred first-line treatment, with high-dose formulations (2 g twice daily) reserved for patients with recent antibiotic use, severe symptoms, age >65 years, or comorbidities. 1

Confirming the Diagnosis Before Treatment

Before prescribing antibiotics, confirm bacterial sinusitis using one of three clinical patterns 2:

• Persistent symptoms: Nasal discharge or daytime cough lasting ≥10 days without improvement 2
• Severe onset: Fever ≥39°C (102°F) with purulent nasal discharge for ≥3 consecutive days 1, 2
• "Double sickening": Initial improvement followed by worsening of symptoms after 5-7 days 2, 3

Critical pitfall: 98-99.5% of acute rhinosinusitis is viral and resolves spontaneously within 7-10 days—do not prescribe antibiotics for symptoms lasting <10 days unless severe presentation is present 2. Antibiotics are overprescribed in 81-92% of cases despite only 0.5-2% having true bacterial etiology 2.

First-Line Antibiotic Selection

Standard Patients (No Risk Factors)

Amoxicillin-clavulanate 875 mg/125 mg twice daily for 5-10 days is the preferred first-line agent 1, 2. Plain amoxicillin 500 mg twice daily (mild disease) or 875 mg twice daily (moderate disease) remains acceptable for uncomplicated cases without recent antibiotic exposure 2.

High-Risk Patients Requiring High-Dose Therapy

Use high-dose amoxicillin-clavulanate (2 g amoxicillin/125 mg clavulanate twice daily) for patients with 1:

• Antibiotic use within the past month
• Moderate to severe symptoms or protracted symptoms
• Age >65 years
• Comorbid conditions (diabetes, chronic cardiac/hepatic/renal disease)
• Immunocompromised state
• Frontal or sphenoidal sinusitis
• History of recurrent sinusitis
• Geographic regions with >10% penicillin-nonsusceptible S. pneumoniae

The high-dose formulation provides enhanced coverage against penicillin-resistant S. pneumoniae and β-lactamase-producing H. influenzae and M. catarrhalis 1, 2.

Penicillin-Allergic Patients

Non-Severe/Delayed-Type Reactions (Rash, Mild Reactions)

Second- or third-generation cephalosporins are safe and preferred 1, 2, 4:

• Cefuroxime-axetil (second-generation) 2
• Cefpodoxime-proxetil (third-generation, superior H. influenzae activity) 2
• Cefdinir (third-generation, excellent coverage and patient acceptance) 2, 4

The risk of cross-reactivity between penicillins and second/third-generation cephalosporins is negligible 2.

Type I Hypersensitivity (Anaphylaxis) or Severe Beta-Lactam Allergy

Respiratory fluoroquinolones are the treatment of choice 1, 2:

• Levofloxacin 500 mg once daily for 10-14 days 1, 2, 5
• Moxifloxacin 400 mg once daily for 10 days 1, 2

Alternative option: Doxycycline 100 mg once daily for 10 days provides adequate coverage against penicillin-susceptible pneumococci but has limited H. influenzae activity with 20-25% predicted bacteriologic failure rates 1, 2.

Critical contraindications 1, 2:

• Never use azithromycin or macrolides: Resistance rates exceed 40% for S. pneumoniae and 20-25% overall
• Never use trimethoprim-sulfamethoxazole: Resistance rates are 50% for S. pneumoniae and 27% for H. influenzae

Treatment Duration

Standard duration is 5-10 days, with most guidelines recommending treatment until symptom-free for 7 days (typically 10-14 days total) 1, 2. Shorter 5-7 day courses have comparable efficacy with fewer adverse events (odds ratio 0.79) 1.

Treatment Failure Protocol

Reassess at 3-5 days 1, 2:

• If no improvement or worsening, switch to second-line therapy
• If partial response, continue current antibiotic for another 10-14 days or consider second-line options

Second-Line Options After Treatment Failure

Switch to respiratory fluoroquinolones 1, 2:

• Levofloxacin 500-750 mg once daily for 10-14 days (90-92% predicted clinical efficacy) 2, 5
• Moxifloxacin 400 mg once daily for 10 days 2

Alternative: High-dose amoxicillin-clavulanate (4 g/250 mg per day) if not already tried 2.

For patients unable to tolerate oral medications: Ceftriaxone 1-2 g IM/IV once daily for 5 days provides 90-92% efficacy with once-daily dosing 2.

Adjunctive Therapies That Actually Work

Intranasal Corticosteroids (Strongly Recommended)

Mometasone, fluticasone, or budesonide twice daily should be added to antibiotic therapy in both acute and chronic sinusitis 1, 2. These reduce mucosal inflammation, improve symptom resolution, and have minimal systemic absorption with strong evidence from multiple RCTs 2.

Symptomatic Relief

• Analgesics (acetaminophen, NSAIDs) for pain and fever 2
• Saline nasal irrigation provides symptomatic relief and removes mucus 2
• Decongestants (pseudoephedrine) may provide relief, though evidence is limited 2

Oral Corticosteroids (Limited Role)

Short-term oral corticosteroids (typically 5 days) may be reasonable for patients with marked mucosal edema or failure to respond to initial treatment 2. Never give systemic corticosteroids without antibiotics when bacterial sinusitis is suspected, as this may suppress immune response and allow bacterial proliferation 2.

Watchful Waiting Option

For adults with uncomplicated acute bacterial sinusitis, watchful waiting without immediate antibiotics is appropriate when reliable follow-up can be assured 2. Instruct patients to start antibiotics only if no improvement by 7 days or worsening at any time 2. Approximately 90% of patients improve naturally within 7-15 days, and antibiotics only slightly increase symptom relief with a number needed to treat of 10-15 2.

Pediatric Considerations

Standard Dosing

• Amoxicillin 45 mg/kg/day in 2 divided doses for uncomplicated disease 2, 3
• High-dose amoxicillin 80-90 mg/kg/day in 2 divided doses for age <2 years, daycare attendance, recent antibiotic use, or high local resistance 2, 3
• High-dose amoxicillin-clavulanate 90 mg/kg/day of amoxicillin component with 6.4 mg/kg/day clavulanate in 2 divided doses for children with risk factors 2, 3

Treatment Duration

10-14 days total, with reassessment at 72 hours 3. If worsening or no improvement at 72 hours, switch to high-dose amoxicillin-clavulanate 3.

Penicillin-Allergic Children

Cefdinir, cefuroxime, or cefpodoxime are first-line for documented penicillin allergy 4. Never use azithromycin or trimethoprim-sulfamethoxazole due to significant resistance 4.

Red Flags Requiring Urgent Evaluation

Obtain immediate imaging and specialist consultation for 3, 4:

• Periorbital or orbital swelling
• Impaired extraocular muscle function or visual acuity
• Severe headache, altered mental status, or seizures
• Focal neurologic findings

Initiate IV vancomycin plus ceftriaxone or cefotaxime immediately for suspected orbital or intracranial complications 3.

When to Refer to Otolaryngology

Refer patients with 2:

• Symptoms refractory to two courses of appropriate antibiotics
• Recurrent sinusitis (≥3 episodes per year)
• Suspected complications (orbital cellulitis, meningitis)
• Need for sinus aspiration/culture in immunocompromised patients

Critical Pitfalls to Avoid

• Do not prescribe antibiotics for viral rhinosinusitis lasting <10 days unless severe symptoms present 2
• Do not use mucus color alone to determine antibiotic need—color reflects neutrophils, not bacteria 2
• Reserve fluoroquinolones for second-line therapy or severe beta-lactam allergy to prevent resistance 1, 2
• Never use first-generation cephalosporins (cephalexin) due to inadequate H. influenzae coverage 2
• Complete the full antibiotic course even after symptoms improve to prevent relapse 2
• Reassess at 3-5 days (adults) or 72 hours (children)—do not continue ineffective therapy beyond this timepoint 2, 3