Differentials
External otitis
SIGNS / SYMPTOMS
Foul-smelling otorrhoea is present frequently.
INVESTIGATIONS
Diagnosis is clinical.
Keratosis obturans
SIGNS / SYMPTOMS
Layers of keratin debris lining the circumference of the bony ear canal and often extending onto the tympanic membrane. May cause partial or total ear canal obstruction. After removing the keratin debris the underlying skin of the bony canal often appears red and friable. Keratosis obturans may result in blunting of the angle between the ear canal and the tympanic membrane.
INVESTIGATIONS
Diagnosis is clinical.
Polyp of ear canal
SIGNS / SYMPTOMS
Signs of infection and purulent otorrhoea. Visualisation of polyp covered by skin or granulation tissue partially or totally occluding the ear canal.
INVESTIGATIONS
Audiogram usually shows a conductive hearing loss.
High-resolution CT scan shows middle-ear and mastoid disease.
Foreign body in ear canal
SIGNS / SYMPTOMS
There may be no differences in signs and symptoms, although there may be a history of foreign-body insertion into the ear canal. Diagnosed by visualisation of a foreign object in the ear canal (e.g., plastic toy, pebble, insect).
INVESTIGATIONS
Diagnosis is clinical.
Osteoma of ear canal
SIGNS / SYMPTOMS
Visualisation of bony-hard skin covered mass(es) that protrude into the lumen of the ear canal, causing partial or total obstruction of the ear canal.
INVESTIGATIONS
High-resolution CT scan will demonstrate a mass, but diagnosis is usually made on the basis of the physical exam.
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