Otitis Externa

Otitis Externa is a topic covered in the 5-Minute Emergency Consult.

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  • Inflammation or infection of the auricle, auditory canal, or external surface of the tympanic membrane (TM):
    • Spares the middle ear
    • Affects 4/1,000 persons in US
  • Also called “swimmer's ear” due to the usual history of recent swimming:
    • Occasional cases after normal bathing
  • Necrotizing (malignant) otitis externa:
    • Infection starts at the ear canal and progresses through periauricular tissue toward the base of the skull
    • Occurs in elderly, diabetic, or other immunocompromised patients
    • Caused by Pseudomonas aeruginosa
    • Can lead to cellulitis, chondritis, and osteomyelitis
    • Associated with 20% mortality


  • Often precipitated by an abrasion of the ear canal or maceration of the skin from persisting water or excessive dryness
  • Predisposing factors include:
    • History of ear surgery or TM perforation
    • Narrow or abnormal canal
    • Humidity
    • Allergy
    • Eczema
    • Trauma
    • Abnormal cerumen production
  • P. aeruginosa, Staphylococcus aureus, streptococcal species, and rarely fungi

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