Bilateral Mastoiditis from Red Tide Exposure

BackgroundBilateral mastoiditis in adults has previously been reported only in association with diabetes mellitus or immunocompromised patients.ObjectivesTo describe a case of bilateral mastoiditis in a healthy adult and to investigate the etiology.Case ReportA 53-year-old woman presented to the Emergency Department with bilateral otitis externa and mastoiditis after scuba diving during a harmful algal bloom, commonly known as a “red tide.” The levels of coliform bacteria recorded at the time and location of her dive exceeded health regulatory limits and correlate with her atypical culture results.ConclusionElevated bacterial counts that result from harmful algal blooms may account for this rare infection.