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Otitis Externa in Dogs
What is Otitis Externa?
The external ear consists of a tube of skin which extends down to the ear drum. The term
otitis externa literally means inflammation of the external ear. There are many reasons
for this but generally otitis externa is due to infection (primary or secondary) by either
bacteria or yeast organisms or a combination of both.
What causes the symptoms we see?
Inflammation, pain, mucky/dirty ears, bad odour, flicking ears, shaking head. These are
all signs which may be seen in a dog with otitis externa. Infection leads to inflammation
of the skin and glands of the canal. This inflammation leads to the overproduction of a
modified cerumen (ear wax) which leaks out of the canal and has a bad smell. There may
also be ulceration of the skin. Pain and irritation from all this leads to shaking &
scratching of the ears.
Why do dogs get infections in their ears?
All dogs will have organisms (bacteria & yeast) in their ears when healthy. Generally
when otitis occurs there is an upset in the normal balance and populations of these
organisms. Sometimes it happens only once every now and then whereas some dogs seem to
have continual ear problems.
This generally means that there is possible some factor that is making this dog more
Ear canal shape - a very narrow or irregular shaped canal will not drain or be
ventilated as well and this may increase susceptibility to infection
Chronic build up of 'muck' - if the ears aren't properly cleaned after a about of otitis
externa there may be residual infection with the muck which will keep recurring.
Allergic skin disease - the external ear canal is just an extension of the skin. Any
condition effecting the skin will have the same or worse effect in the ear canal
Hormone disorders - relatively uncommon but we will consider testing for them if we
can't identify other reasons for recurrent ear problems (eg Thyroid and Adrenal disorders)
Foreign body - eg grass seed or dead insect
Resistant bacteria - some bacteria are resistant to the ear medications we have to use.
In such cases we need to perform a culture and sensitivity test on the exudate
Moisture - some dogs that swim end up with moisture in their ears which increases the
chance of infection.
What about hairy ears?
The general thinking is that hair ear canals should not be plucked unless there is
infection present or the hairs are actually growing down the canal rather that out. The
hair that grows out of the canal acts a bit like a wick and plucking this hair in a normal
canal can inflame the hair follicle leading to infection.
In many cases of otitis it is difficult and painful to pass a scope deep within the ear as
it causes too much discomfort. In most ear problems we will make a smear of the material
in the ear and view it under the microscope. This will often give us more useful
information than looking into the ear. From the smear we can see if an infection is
present and, if so, what the predominant infecting agent is (ie yeast or bacteria or
both). If we suspect a nasty infection from this test we will sometimes take a special
swab to be sent to the lab for culture & sensitivity
This will depend on the diagnosis. There are many ointments available which will control
the populations of bacteria or yeast or both. It is usually important for the ears to be
clean if these ointments are to work properly so we will often prescribe an ear cleaner as
well. In severe or painful cases an general anaesthetic may be required for this.
Prevention of Otitis Externa
1. Address underlying cause if one has been diagnosed - this requires a trip to the Vet
2. Regular cleaning and drying using a specific ear cleaner
Some very useful ear cleaners which can be used in dogs and cats:
|paw gentle ear cleaner
An all natural blend of cold pressed citrus oils with milk protein hydrolysates & deionised water. This unique formula removes & reduces wax build-up and ear odours
kleo ear cleaner
A cleansing agent used as an aid in the treatment & prevention of Otitis Externa in dogs. kLeo has a drying antiseptic action. Soft applicator. Contains boric acid, menthol & chlorothymol
|bayer ear cleaner
Contains esterases, lipase & other
enzymes derived from natural materials. Is non-toxic, non-irritating.
The enzymes soften & dissolve ear wax & debris