Otitis Externa

Basics

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 the U.S.
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 (chemo, steroids)
- Caused by Pseudomonas aeruginosa
- Can lead to cellulitis, chondritis, and osteomyelitis
- Associated with 20% mortality (50% if untreated)
Chronic otitis externa:
- Common
- Caused by over manipulation
- Incomplete treatment of OE

Often precipitated by an abrasion of the ear canal or maceration of the skin from prolonged water exposure or excessive dryness
Predisposing factors include:
- History of ear surgery or TM perforation
- Narrow or abnormal canal
- Humidity
- Allergy
- Eczema
- Trauma
- Abnormal cerumen production
Most common bacteria:
- P. aeruginosa
- Staphylococcus aureus
- Streptococcal species
Otomycosis – secondary to fungus species such as Candida or Aspergillus

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