Otitis Externa (Ear Infections)

Submitted by Veterinary Wellness Partners on Tue, 12/02/2014 - 10:28am

Ear Infections

Otitis Externa

One of the most common reasons (Top Ten Medical Conditions of Dogs) that a dog or cat presents to the veterinarian for a non-routine appointment is due to ear infections.  The medical term for ear infections in dogs is otitis and can be separated into three categories:  otitis externa, otitis medialis and otitis interna (also know as outer ear, middle ear and inner ear infections).  The majority of ear infections in animals are outer ear infections (Otitis externa).  This involves the outer portion of the ear, which is made up of the vertical and horizontal ear canals.  

Contrary to popular belief, outer ear infections are most often a symptom of allergies.  While allergies are the main cause, there are a few risk factors that can help contribute to ear infections.  These include floppy ears, narrow ear canals, repeated exposure of the ears to water and certain breeds.  

Another common misconception is that ear mites are the main reason for ear infections.  The truth is that ear mites are rarely the cause of ear problems in adult animals.  Ear mites are almost exclusively a problem of young kittens and some young dogs.  If we happen to see ear mites in an older animal, we always try to determine if there are young animals in the environment.  Otherwise we start to be concerned about other issues and disease process that may be going on within your pet because this can be a sign of a non working immune system.

Symptoms:  Many of the symptoms are related to the discomfort that is experienced in the ear canal itself.  Animals experience a itching sensation, as well as pain and warmth at the site of infection.  Many owners will notice constant shaking of the head.  Other signs include rubbing the ears on the ground, rubbing the side of the face along the couch, pawing at the ears and holding the head down to relieve the discomfort.  In addition, owners may notice redness/ inflammation of the ear.  Oftentimes a very distinct odor can be detected.

Additional problems and symptoms may bee noted.  These include a major swelling of the ear flap (called an aural hematoma).  This requires surgery.  Any abnormal head positioning or eye movement is a sign that you need to get your pet seen as soon as possible.  This may indicate a middle or inner ear infection.  These infections are more complicated and require more aggressive therapy.

Diagnosis:  The first step in diagnosis is the physical examination.  Using the otoscope, one of our veterinarians will take a look at both the vertical and horizontal ear canal.  We may determine the need to clean the ear canals so that we are able to better see the tympanic membrane (Ear drum).  Most of the time, we will take a small sample of debris from both ears and run a test to determine both the type of infection and the treatment that is the most likely to resolve the ear infection.

Typically we classify an ear infection into three broad categories:

  1. Yeast Otitis Externa:  Ear infections caused by yeast are the most common type of ear infection. Fortunately, these infections also tend to be the easiest to treat.  (Notice we did not say that they are "easy to treat," simply that they are the least complicated and generally resolve with appropriate treatment)
  2. Small bacterial Infection (COCCI): This is a very broad category, which we call cocci.  We lump these bacteria into one category because they tend to be treated with the same medications.  This is the second most common type of infection that we see in the clinic.  It is more difficult to treat than a yeast infection, but not as concerning as the third category.
  3. Large Bacteria (RODS):  This category is the least common that we see, but the most aggressive and hardest to treat.  Oftentimes, an infection with rods will take multiple treatments to resolve.  We typically recheck these pets two weeks into the treatment and repeat a test to see if the infection is going away. Many times, we are able to treat the aggressive infection caused by these large bacteria, but the infection changes to one of the other categories.  

Treatment:  Treatment for the specific ear infection will vary depending on the results of the physical examination and the cytology testing that we perform in the clinic.  Most treatments involve some form of ear cleaning and then a treatment that is placed into the ear.  Our technician or veterinarian will demonstrate the proper way to clean the ear canals.  Generally, we recommend cleaning the infected ears once a day for one week and then every other day for the second week.  We then give you instructions on when to apply the ear medication, which is either once a day or twice a day for two weeks.  Some ear infections can also be treated using a medication that we can place into the ear canal.  This treatment will stay in the ear canal and treat the infection for 2 to 3 weeks depending on each case.  

Animals that have a more aggressive infection may be placed on additional medications.  These include oral antibiotics and NSAIDs.  NSAIDs are medications that target both inflammation and pain.

Prevention:  While there is no way to truly prevent ear infections, there are things that can be done to help.  For dogs and cats that have chronic, repeated ear infections; we recommend cleaning the ears twice a week.  This helps to keep the ear canal free of debris, as well as removes gunk and organisms from the ear canal.  Routine cleaning also helps to detect an ear infection early on.  It is also a good idea to clean the ears after any time that your pet has been in water.  This includes after a bath and after swimming.  This helps to remove the water and moisture from the ears, which is one thing that can lead to ear infections.   

We recommend cleaning your pet's ears only with an approved ear cleaner for animals.  We sell several different types and brands.  For most animals, a general ear cleaner is recommended.  Sometimes we will recommend using a specific ear cleaner that may be better for a specific case.  These ear cleaners may be more effective at dissolving the ear debris or may change the pH levels within the ear canal.  We never recommend a home remedy in the ears.  Home remedies are not approved for use in pets and often cause more harm that good.  These include vinegar and hydrogen peroxide.  It is especially important to avoid these if the ear drum is ruptured.  This is an additional reason why bringing your pet in for a thorough ear examination is vital, because a ruptured ear drum is a complication that can result in permanent damage to your pet's inner ear.