What are causes of malignant otitis externa (MEO)?

Updated: Apr 13, 2020
  • Author: Brian Nussenbaum, MD, FACS; Chief Editor: Arlen D Meyers, MD, MBA  more...
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See the list below:

  • Diabetes (90% of patients)

    • Diabetes is the most significant risk factor for developing malignant external otitis (MEO).

    • Small-vessel vasculopathy and immune dysfunction associated with diabetes are primarily responsible for this predisposition.

    • The cerumen of patients with diabetes has a higher pH and reduced concentration of lysozyme, which may impair local antibacterial activity.

    • No difference in predisposition is found between diabetes types I and II.

    • The predisposition is not necessarily related to the severity of glucose intolerance or periods of hyperglycemia.

  • Immunodeficiencies, such as lymphoproliferative disorders or medication-related immunosuppression

  • AIDS

    • Malignant external otitis (MEO) associated with AIDS may have a different pathophysiology than classic malignant external otitis (MEO).

    • Patients present with similar symptoms but are generally younger and do not have diabetes.

    • Granulation tissue may be absent in the external auditory canal.

    • Pseudomonas is not necessarily the dominant causative organism.

    • Patients with AIDS generally have a poorer outcome than patients with diabetes.

  • Aural irrigation: As many as 50% of cases of malignant external otitis (MEO) have been reported to be preceded by traumatic aural irrigation in patients with diabetes.

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