A 6-year-old boy presents with 2 days of right ear pain, fever of 38.8°C, and decreased appetite. Otoscopy shows a bulging, erythematous tympanic membrane with poor mobility. The parents have no reported antibiotic allergies. Which of the following is the most appropriate first-line antibiotic regimen?

Question

Accepted Answer

✅ B. Amoxicillin 80–90 mg/kg/day divided BID × 10 days
Per AAP guidelines, amoxicillin at high dose (80–90 mg/kg/day divided BID) for 10 days is first-line for acute otitis media in a previously healthy child with no recent amoxicillin use, no conjunctivitis, and no antibiotic allergy. The high dose is specifically chosen to overcome intermediate-resistance S. pneumoniae, the most common pathogen.

❌ A. Amoxicillin 40 mg/kg/day divided TID × 5 days
The dose is too low to reliably cover resistant S. pneumoniae (the older 40 mg/kg/day dosing is no longer recommended for AOM), and the 5-day course is too short for a child < 6 years old — 10 days is standard for young children.

❌ C. Amoxicillin-clavulanate 90 mg/kg/day
Amoxicillin-clavulanate is reserved for second-line therapy: patients with amoxicillin use in the past 30 days, concurrent conjunctivitis (suggesting H. influenzae), AOM that has failed amoxicillin, or recurrent AOM. It would be correct if this child had received amoxicillin within 30 days.

❌ D. Azithromycin × 5 days
Azithromycin is an alternative only for patients with severe (type I, anaphylactic) penicillin allergy and has poor activity against S. pneumoniae because of high macrolide resistance. It should not be used as first-line in a child without an allergy.

:::pearl
Pediatric AOM first-line: high-dose amoxicillin 80–90 mg/kg/day BID × 10 days (< 6 y/o). Step up to amoxicillin-clavulanate if failure, recent amox, or conjunctivitis.
:::

Amoxicillin

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