Ear Infections (Otitis Externa)

Advice on ear infections and general cleaning

27 October 2016

Unlike the human ear, the structure of a pet's ear makes it prone to infection. This is due to the presence of a vertical ear canal in pets (seen in the figure below) which makes it difficult for wax and debri to work its way upwards (against gravity), than simply just horizontally, like in humans.


 
When an ear becomes irritated, it results in an overproduction of wax. Irritation can be caused by: allergic skin disease, ear mites, foreign bodies such as grass seeds or foxtails, or excessive hair growth deep in the canal (common in poodles and schnauzers). The moisture of the wax promotes bacterial growth and often results in an infection.

Symptoms of a possible ear infection can include, the pet scatching at their ears or excessive shaking of the head. A discharge or odour may also be noticeable to the owner.

Possible Complications

Most ear infections begin in the vertical and horizontal ear canals. When an infection develops further, it may reach the middle ear (seen in the picture above). If the middle ear becomes involved, neurologic signs may develop such as a head tilt, a lack of balance, unusual back and forth eye movements (called nystagmus) or other nervous signs. Middle ear infections can also cause facial paralysis, leading to a droopy jaw or muzzle on one side of the face.

An aural haematoma is another potential complication of an ear infection. An aural haematoma is a blood filled pocket within the skin of the ear flap, caused by damage to the blood vessels in the ear from excessive head shaking or trauma to the ear such as the pet scratching the ear. The usual recommendation is to have the aural haematoma drained, and the clots removed under anaesthesia. A large number of sutures are placed to keep the skin of the ear together until it heals, to prevent the ear flap ballooning out with blood once more. Without surgery, the ear may scar down into an abnormal cauliflower edged appearance.

 
 
A cat with a blood filled aural haematoma
 
Diagnosing And Treatment

If your pet is scratching their ears excessively, shaking their head, or a foul smelling discharge can be smelt, a visit to your veterinarian is in order. An active ear infection can only be properly treated with the appropriate prescription medication, not with ear cleaners alone. Over the counter ear cleaners are great, and are useful in the treatment of an ear infection, but should only be used on their own during the preventive stage as an aid in preventing an infection from occuring in the first place.

The type of medication administered for your pet's ear infection by your veterinarian, will depend on the type of infection present.

To find out what infection is present, your vet will take a swab of the discharge from your pet's ear and examine it under a microscope. Along with a swab, your vet will use a device called an otoscope to look down your pets ear to check for foriegn objects, like grass seeds, and to check whether the ear drum is still in tact.

Under the microscope, your vet will be looking for whether the infection is due to bacteria or yeast and also if ear mites are present.

Certain types of bacteria, which have an unusual rod shaped appearance under the microscope, are often signs of a more sinister infection. If seen, your vet will recommend a swab be sent to the laboratory for culture and antibiotic testing, as these bacteria are often resistant to many types of antibiotics and will need quick and accurate treatment as soon as possible.

Your vet may also prescribe oral medication, including a short course of low dose steroids to help relieve the inflammation in the ear and improve drainage.

Along with medications, your vet will recommend an appropriate ear cleaner to help remove the wax and infection from the ear canal, to allow the prescription medication to penetrate the canal and be more effective. Commonly recommended ear cleaners for this purpose include: Epi-Otic, PAW Gentle Ear Cleaner, or Bayer Ear Cleaning Solution.

 

Epi-Otic - a popular ear cleaning agent.


Reoccuring Infections

Reoccuring infections tend to have an underlying cause such as an allergy, which should always be investigated. These cases generally should have a swab of the ear infections cultured at the laboratory to ensure there are not resistant organisms present that may require a change in medication to treat.

When ear infections occur repeatedly, often the repetitive inflammation may cause scar tissue to form, blocking the ear canal making it even more difficult to treat. In these cases, surgery is often required to open up the vertical canal so that only the horizontal canal remains, in a procedure called ear ablation.

 

After reoccuring ear infections, excessive scarring and tissue growth, requiring surgery.



Preventing Ear Infections

Recommended products: Epi Otic , PAW Gentle Ear Cleaner, or Bayer Clean Ear Solution

Regular ear cleaning is important to remove the excessive buildup of wax and debri and prevent an infection becoming rooted in your pet's ears. Ear cleaning, with a little practice, can easily be done at home. Make sure you clean your dog's ears outdoors or in an area that can be easily cleaned as pets will often shake and make a mess.

Use a two stage cleaning technique. First, flood the ear canal with cleaning solution. Make sure you fill the canal - don't just use a few drops. Allow the solution to remain in the canal for at least 60 seconds and gently massage the entire canal during this time while holding the tip of the ear up with the other hand. Dry the canal using a cotton ball. Use only real cotton balls, which are less irritating than synthetic ones. Never clean your pet's ears with a cotton swab or tip. The swab pushes debris further into the ear canal and puts the eardrum under pressure, possibly causing it to rupture.

The second stage, is to repeat the first. Again, allow the solution to contact the canal for a full 60 seconds and massage the ear. Then step back and let your dog shake its head as the liquid is expelled.

The frequency of cleaning varies depending on how severe your dog's ears are affected, as well as how often they go swimming or get dirty. In general, perform this cleaning process once or twice a week. If your veterinarian diagnoses an active ear infection, you may be advised to incease this frequency of cleaning to twice a day for the first few weeks.

Ensure you follow your vet's instructions for cleaning and administering any medications. Be sure to bring your pet back for a repeat appointment after the treatment has finished or sooner depending on your vet's instructions. A recheck will ensure that the infection is completely taken care of, or it may indicate that a little longer on the medication is required.  Ear infections also often reoccur in pets, and the medication that cleared it up the last time may not work the next time, because the type of infection may be completely different. So be sure to see your vet if signs reoccur.

For any questions about ear infections, please feel free to ask our vets at info@mammothpetsupplies.com.au

Last edited: 26 November 2012

* The above is general vet advice and is not to be used exclusively. If your pet is showing any of the symptoms mentioned above, please consult your veterinarian without delay.