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OTITIS EXTERNA

Note for Pet Owners:
This information is provided by Provet for educational purposes only.

You should seek the advice of your veterinarian if your pet is ill as only he or she can correctly advise on the diagnosis and recommend the treatment that is most appropriate for your pet.

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Description
Otitis externa is inflammation of the outer ear canal.


Cause
There are many primary causes of otitis externa including :

 


Breed Occurrence
Animals with narrow auditory canals and flop ears are more likely to develop otitis externa than others. Cocker spaniels may develop glandular hypertrophy and German Shepherd Dogs are reported to have an increased predisposition. Working dogs and pet dogs that are exercised in rural areas are more likely to get grass awns and other vegetative foreign objects in their ears.


Signs
There are many signs including :

  • Reddening of the skin of the pinna
  • A visible, often smelly, discharge in the outer ear canal. This can be any colour from black, brown, red-brown, red, yellow, to off-white.
  • Head shaking
  • Scratching at the affected ear(s)
  • Drooping of the affected ear
  • Pain when eating (if complicating otitis media involves tempero-mandibular joint)
  • Holding the head to one side, (to the side of the affected ear)
  • Walking in circles
  • Fitting - if complicated by otitis media/interna

Complications
Bacteria and yeasts are common secondary infections (they are rarely a primary cause). Chronic otitis externa leads to thickening of the skin of the pinna, with hyperplasia, hyperkeratosis, fibrosis and calcification. Swelling of the tissues closes off the auditory canal leading to reduced natural ventilation.

If the tympanic membrane is diseased or ruptured otitis media may develop with osteomyelitis. 


Diagnosis
Thorough examination of the external ear canal with an auroscope is necessary to identify the presence of a foreign object. To get good visibility may require cleaning the wax and debris out of the canal and a general is needed in some cases to get good visibility of the horizontal canal and tympanic membrane.

Other diagnostic tests that may be helpful include :

  • Cytological examination of the discharge in the ear canal
  • Culture an sensitivity testing of swabs taken from the canal
  • Biopsy and histopathological examination

Treatment
There are several forms of treatment :


Prognosis
Good if treated early. Guarded with chronic otitis externa ..can have a protracted course and .may result in surgery being needed.


Long term problems
Hearing loss. Recurrences are common

 

Updated October 2013

 
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