How do I assess and manage acute sinusitis in a child, including criteria for bacterial infection and appropriate antibiotic selection and dosing?

Assessment and Management of Acute Bacterial Sinusitis in Children

Clinical Diagnosis

Diagnose acute bacterial sinusitis in children aged 1-18 years using entirely clinical criteria—imaging is not required for uncomplicated cases. 1, 2

The diagnosis requires one of three distinct clinical patterns:

• Persistent illness: Nasal discharge (any quality) or daytime cough lasting >10 days without improvement 1, 2
• Severe onset: Fever ≥39°C (102.2°F) plus purulent nasal discharge for ≥3 consecutive days 1, 2
• Worsening course: New fever ≥38°C or substantially increased nasal discharge/cough after initial improvement from a viral URI 1, 2

Key distinction from viral URI: Most viral infections resolve by day 10, with mucus progressing from clear to cloudy then improving; persistence beyond 10 days indicates bacterial superinfection. 2

Common Diagnostic Pitfall

Do not attribute symptoms lasting >10 days to a "simple cold"—this duration indicates likely bacterial infection requiring treatment. 2 Fewer than 1 in 15 children with viral URIs develop true bacterial sinusitis. 1

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Imaging Recommendations

Do not obtain sinus imaging (X-ray, CT, ultrasound) for uncomplicated acute bacterial sinusitis. 1, 2, 3

Rationale for avoiding routine imaging:

• More than 50% of children with viral URIs show abnormal sinus radiographs 2
• 42% of healthy children have sinus abnormalities on imaging 2, 3
• Imaging does not change management in uncomplicated cases 1, 2

Reserve contrast-enhanced CT exclusively for suspected complications:

• Orbital: Periorbital swelling, proptosis, impaired extraocular movements, vision changes 1, 2, 4
• Intracranial: Severe headache, photophobia, altered mental status, seizures, focal neurologic deficits 1, 2, 4

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First-Line Antibiotic Therapy

Prescribe standard-dose amoxicillin 45 mg/kg/day divided twice daily for 10-14 days (or until symptom-free for 7 days) as first-line therapy. 1, 2, 5

Evidence Supporting Antibiotic Use

The number needed to treat (NNT) with antibiotics is 3-5 to achieve clinical cure, demonstrating substantial benefit over observation. 2

Microbiology (Post-Pneumococcal Vaccine Era)

Pathogen	Prevalence
Streptococcus pneumoniae	~30% [2,5]
Nontypeable Haemophilus influenzae	20-30% [2,5]
Moraxella catarrhalis	10-20% [2,5]

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Risk-Based Escalation to High-Dose Therapy

Use high-dose amoxicillin (80-90 mg/kg/day) or high-dose amoxicillin-clavulanate (90 mg/kg/day of amoxicillin component) when ANY of these risk factors are present: 1, 2, 5

• Age <2 years
• Daycare attendance
• Antibiotic use within past 4-6 weeks
• Geographic area with high prevalence of penicillin-resistant S. pneumoniae

For children without these risk factors, start with standard-dose amoxicillin. 2

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Observation vs. Immediate Treatment

For persistent illness only (symptoms >10 days without worsening):

• Either immediate antibiotics OR 3-day observation period is acceptable 1, 2
• Observation may be considered when symptoms are mild and quality of life is minimally affected 1

For severe or worsening presentations: Start antibiotics immediately—observation is not appropriate. 1, 2

Critical Caveat

At 21 days of symptoms, observation is no longer appropriate; antibiotic therapy is mandatory due to prolonged impairment of quality of life. 2

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Mandatory 72-Hour Reassessment

Re-evaluate every child exactly 72 hours after starting amoxicillin to detect treatment failure or complications. 2, 3, 4

Action Algorithm at 72 Hours:

If worsening symptoms (new fever, increased purulent discharge, severe headache):

• Switch immediately to high-dose amoxicillin-clavulanate (90 mg/kg/day of amoxicillin component) 2, 3, 4

If no improvement (symptoms unchanged):

• Consider escalation to high-dose amoxicillin-clavulanate 2, 3

If orbital signs develop (periorbital swelling, proptosis, ophthalmoplegia):

• Obtain urgent contrast-enhanced CT 1, 2, 4
• Consult ophthalmology/ENT immediately 1, 2

If intracranial signs develop (altered mental status, severe headache, focal deficits):

• Obtain emergent CT with contrast 1
• Consult neurosurgery 1
• Start IV vancomycin to cover methicillin-resistant S. pneumoniae 1

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Alternative Antibiotics for Penicillin Allergy

For type 1 or non-type 1 penicillin hypersensitivity, use: 1

• Cefdinir
• Cefuroxime
• Cefpodoxime

Do NOT use trimethoprim-sulfamethoxazole or azithromycin due to high resistance rates among S. pneumoniae and H. influenzae. 1

For culture-proven penicillin-resistant S. pneumoniae in allergic patients, clindamycin may be indicated. 6

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Management of Treatment Failure After Amoxicillin

If symptoms persist or worsen after completing standard amoxicillin, switch to high-dose amoxicillin-clavulanate (90 mg/kg/day of amoxicillin component) for at least 10 days. 3

The addition of clavulanate provides coverage against beta-lactamase-producing organisms (H. influenzae, M. catarrhalis) that cause treatment failures. 3

If second-line therapy fails:

• Consider IM/IV ceftriaxone 50 mg/kg once daily 1
• Obtain ENT referral for possible imaging or procedural intervention 3
• Re-evaluate diagnosis: consider allergic rhinitis, anatomic abnormalities, immunodeficiency 3

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Adjuvant Therapies

Do not use antihistamines as primary treatment for acute bacterial sinusitis, although they may help allergic symptoms in atopic children. 1, 2

There is insufficient evidence to recommend intranasal corticosteroids, saline irrigation, decongestants, or mucolytics for acute bacterial sinusitis in children. 1

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Recurrent Acute Bacterial Sinusitis

Recurrent disease is defined as ≥4 episodes per year, each lasting <30 days, separated by ≥10 symptom-free days. 1, 2

Evaluate for underlying conditions: 1, 2

• Allergic rhinitis
• Immunoglobulin deficiency (IgA, IgG2)
• Cystic fibrosis
• Gastroesophageal reflux disease
• Ciliary dyskinesia
• Anatomic abnormalities (septal deviation, nasal polyps, concha bullosa)

Contrast-enhanced CT, MRI, or endoscopy should be performed to detect obstructive conditions in recurrent cases. 1

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Critical Pitfalls to Avoid

• Do not delay antibiotics once symptoms exceed 10 days; brief observation is only permissible at exactly 10 days, not at 3 weeks 2
• Do not obtain imaging in uncomplicated cases—diagnosis is clinical 1, 2, 3
• Do not start with amoxicillin-clavulanate unless risk factors for resistant organisms are present 2
• Do not skip the 72-hour reassessment—this is when treatment failures and complications are detected 2, 3, 4
• Do not use supportive care alone once symptoms persist >10 days—antibiotics provide higher cure rates 2