Start Amoxicillin Immediately
For a pediatric patient with frontal tenderness developing 3 days after URTI onset, you should start amoxicillin immediately without obtaining a CT scan. This presentation meets criteria for acute bacterial sinusitis with a "worsening course," which mandates antibiotic therapy 1.
Why This is Acute Bacterial Sinusitis Requiring Treatment
The development of frontal tenderness after 3 days of URTI symptoms represents a worsening course—defined as new onset or worsening symptoms (including fever, daytime cough, or nasal discharge) after initial URTI symptoms 1. This is one of three diagnostic patterns for acute bacterial sinusitis in children, alongside severe presentation (≥39°C fever with purulent discharge for 3-4 consecutive days) and persistent symptoms (>10 days without improvement) 2, 1.
- Frontal sinusitis specifically requires definitive antibiotic treatment according to French guidelines, as it carries higher risk of complications 1.
- The American Academy of Pediatrics explicitly states that clinicians should prescribe antibiotic therapy for children with a worsening course presentation 1.
Why CT Scan is NOT Indicated
Imaging studies of any kind should not be obtained for diagnosis of uncomplicated acute bacterial sinusitis 1. The diagnosis is clinical, based on symptom patterns, not radiographic findings 2, 3.
- CT scanning is reserved exclusively for suspected complications such as periorbital/orbital swelling with proptosis, impaired extraocular muscle function, visual changes, severe headache with altered mental status, or signs of intracranial involvement 1.
- Routine imaging does not contribute to diagnosis in uncomplicated cases and exposes children to unnecessary radiation 1, 3.
Antibiotic Regimen
Start amoxicillin 45 mg/kg/day divided every 8-12 hours as first-line therapy 1, 4. However, for frontal sinusitis specifically, consider high-dose amoxicillin-clavulanate (90 mg/kg/day of the amoxicillin component divided every 12 hours) as it provides broader coverage and is preferred for this location 1.
Indications for High-Dose Amoxicillin-Clavulanate:
- Age younger than 2 years 1
- Daycare attendance 1
- Recent antibiotic exposure within past month 1
- Geographic areas with high prevalence of resistant Streptococcus pneumoniae 1
- Severe symptoms at presentation 1
- Frontal sinusitis location 1
Treatment Duration and Mandatory Reassessment
- Treat for 10-14 days total, with minimum of 10 days 1.
- Reassessment is mandatory within 72 hours 1.
- If the child shows worsening symptoms or failure to improve at 72 hours, consider changing to broader-spectrum antibiotic or evaluating for complications that may require imaging 1.
Critical Pitfall to Avoid
Reassurance alone is inappropriate for this presentation. While most viral URTIs resolve spontaneously and do not require antibiotics 2, this child has developed a worsening course with frontal tenderness, which shifts the clinical picture from uncomplicated viral URTI to acute bacterial sinusitis requiring treatment 1. Withholding antibiotics in this scenario risks progression to serious complications including orbital or intracranial extension, particularly given the frontal sinus location 1, 5.