Otoscopy :: THE EXTERNAL CANAL :: Fig7_30
 THE EXTERNAL CANAL  
Acquired External Ear Canal Stenosis

Acquired External Ear Canal Stenosis

Description : Definition
An acquired stricture or narrowing of the external auditory canal most commonly occurring in the region of the isthmus.

Etiology
Canal stenosis may develop as the result of trauma to the skin of the external auditory canal.

The trauma may be the result of an accidental laceration, chronic self manipulation, chronic otitis externa and, on rare occasions, following the use of instruments in the external canal in cases of keratosis obturans.

Once the skin lining the external canal has been lacerated, exuberant granulations within the external canal may epithelialize, producing a resultant skin covered fibrous tissue stenosis.

Symptoms
There are usually no symptoms unless there is an accumulation of wax and debris medial to the stenosis, causing a conductive hearing loss.

Otoscopic appearances
The stricture occurs most commonly in the narrowest portion of the external canal (the isthmus).

The stricture may be wide enough to allow migration of the epithelium from the deep canal to the outside to occur normally.

This patient developed a canal stenosis at the isthmus following removal of keratosis obturans and debridement of granulation tissue. The membranous stenosis is seen at the isthmus and the actual lumen of the canal has been narrowed to approximately 4 mm in diameter.

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