ENT

Otitis externa

Inflammation or infection of the external auditory canal, usually managed with ear care, analgesia and topical treatment; severe persistent pain in a person with diabetes or immunosuppression is a necrotising otitis externa emergency.

Definition

Otitis externa is inflammation or infection of the skin of the external auditory canal, with or without involvement of the pinna. Acute bacterial disease is common, but fungal, eczematous, irritant and necrotising forms require different management.

First principles

The disease is in the skin of the external canal

Water, soap, eczema, hearing devices and mechanical trauma can disrupt the canal's cerumen and epithelial barrier. Bacteria—often Pseudomonas or Staphylococcus—or fungi then cause inflamed, oedematous, painful canal skin. Tragal or pinna tenderness and canal oedema support otitis externa; a separate middle-ear or mastoid process must not be assumed to be the same condition.

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