Occult middle ear and mastoid fluid in acute otitis externa

Objectives/Hypothesis: Presence of fluid in the middle ear (ME) or mastoid air cells in acute otitis externa (OE) has not been reported. We hypothesize that in patients with OE there is often otitis media (occult middle ear and mastoid fluid) and secondary fluid in the mastoid air cell system, which is not seen during a clinical examination because of edema in the external canal skin. Study Design: Retrospective chart review. Methods: We reviewed the medical records of 209 patients who presented to our ear, nose, and throat (ENT) clinic with acute OE that was resolved with oral and/or topical antibiotics. Results: Twenty-seven of the 209 patients presented with unilateral or bilateral acute OE (29 ears) and received a computed tomography (CT) scan of their temporal bones, which was ordered by the Emergency Department or ENT services. Twenty-three of 29 ears (79%) showed fluid in the ME, mastoid, or both. Nine of the 10 patients (82%), who obtained their CT scan within 1 week of symptom onset, were found to have fluid. Conclusions: These findings support our hypothesis and serve to inform the medical community (both ENT and primary care) that fluid is often present in the ME or mastoid in patients with acute OE whose symptoms will resolve with oral and/or topical antibiotics.