Malignant otitis externa


Ear anatomy
  • Life-threatening infection of external ear/canal, soft tissue, +/- spread to skull base
  • Diabetes and immunosuppression are main risk factors
  • Pseudomonas causes >90% of cases
  • Begins as simple otitis externa

Clinical Features


  • Otitis externa that has not resolved despite 2-3wks of topical antibiotics
  • Otalgia often out of proportion for routine otitis externa
  • Edema of external auditory canal
  • Granulation tissue often seen in the ear canal floor
  • Facial nerve often first CN involved[1]
  • CN IX, X, or XI involvement
  • Trismus


  • More rapidly progressive than in adults
  • TM, middle ear, and facial nerve more likely to be affected

Differential Diagnosis

Ear Diagnoses





Malignant external otitis. Axial CT scan in bone window demonstrates destruction of mastoid segment of petrous bone. There were also subtle cortical destructions visible in tympanic bone.
  • Imaging[2]
    • Most authors support CT initially, but CT fails to diagnose early osteomyelitis since 30% bone destruction needed for detection
    • MRI more sensitive for intracranial complications
  • Labs
    • WBC usually normal or slightly elevated
    • Left shift uncommon
    • Elevated ESR and CRP
      • Differentiates from MOE from acute external otitis or malignancy
      • However, not required for diagnosis[3]





  • Contact ENT for disposition decision; early infection may be managed as outpatient


See Also


  1. Pfaff JA, Moore GP: Otolaryngology, in Marx JA, Hockberger RS, Walls RM, et al (eds): Rosen’s Emergency Medicine: Concepts and Clinical Practice, ed 8. St. Louis, Mosby, Inc., 2014, Ch 72.
  2. Nussenbaum B et Al. Malignant Otitis Externa Workup. Medscape, Jul 14 2015.
  3. Hosmer, K: Ear Disorders, in Tintinalli JE, Stapczynski JS, Ma OJ, Yealy DM, Meckler GD, Cline DM (eds): Emergency Medicine, A Comprehensive Study Guide, ed 8. New York, McGraw-Hill, 2016, Ch 242:p 1581-2.