A 16-year-old with otitis externa and diabetes mellitus should be treated with which regimen?

• A. Oral fluoroquinolone
• B. Topical aminoglycoside drops
• C. Topical fluoroquinolone drops
• D. Oral aminoglycoside

Answer: (A)

In otitis externa, diabetes raises concern for deeper, potentially invasive infection such as malignant otitis externa, which can extend to the bone behind the ear. Because of this higher risk, you need systemic therapy that reaches throughout the ear structures and surrounding bone, not just a drop solution confined to the ear canal. An oral fluoroquinolone fits this need well by providing antipseudomonal activity, good tissue penetration (including bone), and the convenience of outpatient treatment. This approach helps cover the probable pathogen, typically Pseudomonas species, and addresses the possibility of spread that topical therapy alone would miss.

Topical aminoglycoside drops are useful for straightforward, uncomplicated otitis externa but don’t reliably treat deeper or bone-involved infection and carry ototoxicity risks. Topical fluoroquinolone drops would be appropriate for uncomplicated cases but may be insufficient when there’s diabetes-related risk for malignant otitis externa. Oral aminoglycosides are not favored due to poor oral absorption and systemic toxicity.