7 Interesting Facts of Necrotizing otitis externa
- Rare, aggressive, severe infection of the external auditory canal, surrounding support structures, and bone (eg, mastoid, temporal bone); over 90% of cases are caused by Pseudomonas
- Many experts regard necrotizing otitis externa as a complication of untreated otitis externa; necrotizing otitis externa may represent a unique, rapidly invasive infectious process and separate pathophysiologic entity from acute otitis externa
- Almost exclusively occurs in adult patients (primarily in elderly people) and patients with immunocompromise (eg, diabetes, HIV); over 90% of patients who develop necrotizing otitis externa have diabetes
- Early in the necrotizing otitis externa disease process, patients can present with similar, but more intense, symptoms (eg, otalgia, otorrhea) as patients with acute otitis externa
- Eventually, patients will develop high fever, malaise, severe pain out of proportion to examination findings, and granulation tissue along the floor of the external auditory canal; may develop cranial nerve palsies, vertigo, and meningeal signs
- Fever and malaise do not occur with otitis externa; differentiate diseases by clinical presentation, disease course, and imaging
- Confirm necrotizing otitis externa by imaging; CT identifies extension of infection outside of the external auditory canal (eg, bony erosion, soft tissue involvement); MRI better characterizes soft tissue abnormalities and identifies retrocondylar fat infiltration, a finding present in 93% of patients with necrotizing otitis externa
