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Otitis externa

Last updated: January 6, 2021

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Otitis externa (OE) refers to inflammation of the external auditory canal, which is most often the result of a local bacterial infection. Risk factors for OE include injury to the skin of the external auditory canal and/or exposure to water. OE is characterized by ear pain, discharge, and tragal tenderness. Otoscopy may reveal a furuncle (localized OE) or a red, edematous external auditory canal (diffuse OE). OE is primarily a clinical diagnosis. Treatment involves keeping the external auditory canal dry and administering fluoroquinolone and hydrocortisone ear drops. Systemic antibiotic therapy is usually indicated in immunosuppressed and/or diabetic patients who are at risk of a more severe variant called malignant otitis externa (MOE). MOE, which is almost always caused by Pseudomonas aeruginosa, may present with facial nerve palsy and is potentially fatal because it spreads rapidly to the base of the skull. Immediate referral and treatment with systemic antipseudomonal antibiotics are indicated.

Malignant otitis externa (necrotizing otitis externa) [1][2]

Malignant otitis externa is a severe infection that is often lethal.

Fungal otitis externa should be suspected when symptoms do not resolve with local and/or systemic antibiotic therapy (especially among immunocompromised and diabetic patients).


  1. Dhingra PL, Dhingra S. Diseases of Ear, Nose and Throat. Elsevier ; 2014
  2. Handzel O, Halperin D. Necrotizing (malignant) external otitis.. Am Fam Physician. 2003; 68 (2): p.309-12.
  3. Otitis Externa: A Practical Guide to Treatment and Prevention. Updated: March 1, 2001. Accessed: April 29, 2020.