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                                            Ear Infections in Dogs & Cats

How common are ear infections in dogs?

Infections of the external ear canal (outer ear) by bacteria or yeast, are one of the most common types of infections seen in dogs.  We call this otitis externa.  Some breeds, such as Cocker Spaniels and Miniature Poodles, seem more prone to ear infections, but they may occur in any breed.

Ear mite infections generally occur most commonly in puppies & cats.  Ear mites in adult dogs occur most frequently after a puppy carrying mites is introduced into the household.  Sometimes, ear mites will create an environment within the ear canal which leads to a secondary infection with bacteria and yeast (fungus).  By the time the dog is presented to the veterinarian, the mites may be gone, but a significant ear infection remains.  

Why some breeds of dogs are more prone to ear infections?

To understand the dog's ear problems better, we must initially understand that the dog's ear canal is anatomically different than that of the human ear. Unlike the human ear, the dog's ear has two compartments. Beginning at the opening of the ear canal, the vertical canal travels downward towards the dog's jaw. Then it makes a 45 degree turn and travels horizontally towards the ear drum. This makes visualization and treatment of the entire canal more difficult. Also, as a rule, most breeds have a much longer ear canal than humans. These differences predispose the dog's ear to infection as well as make treatment more difficult. Dogs with long, pendulous ears, such as Cocker Spaniels, Labrador Retrievers, Basset Hounds and Irish Setters, certainly are more predisposed to ear problems than those breeds with short, erect ears. As the ear folds, it covers the ear canal and prohibits air from entering and drying the canal. The result is a moist, warm ear canal that is a perfect environment for organisms to grow

What are the symptoms of an ear infection?

A dog with an ear infection is uncomfortable; its ear canals are sensitive.  It shakes its head trying to get the debris and fluid out, and it scratches its ears.  The ears often become red and inflamed and develop an offensive odor.  A black or yellowish discharge commonly occurs.

Since these symptoms are similar and usually mean an infection, can I just come by and get some medication?

There are several kinds of bacteria and at least one type of fungus which might cause an ear infection.  Without knowing the kind of infection present, we do not know which drug to use.  In some cases, the ear infection may be caused by a foreign body or tumor in the ear canal. Polyps are more common in cat’s ears. Polyps are removed from the middle ear through special surgical procedure called Ventral Bulla Osteotomy. Treatment with medication alone will not resolve these problems.  Also, the dog must be examined to be sure that the eardrum is intact.  Administration of certain medications can result in loss of hearing if the eardrum is ruptured.  This determination is made by the veterinarian and must be done in the animal hospital office.

How do you find out which drug to use?

First, the ear canal is examined with an otoscope, an instrument that provides magnification and light. This permits a good view of the ear canal.  This examination allows us to determine whether the eardrum is intact and if there is any foreign material in the canal.  When a dog is in extreme pain and refuses to allow the examination, it must sometimes be completed under sedation or anesthesia. 

The next step is to examine a sample of the material from the ear canal to determine which organism is causing the infection.  This is called ear cytology. Ear cytology is a valuable test used to diagnose ear infections in dogs and cats. Cytology detects bacterial (cocci or rods), yeast and parasitic infections. Other cells frequently seen on ear cytology include neutrophils, which are a type of white blood cell which is often present in active infections and epithelial cells, which often slough from the lining of the ear canal. Examination of ear smear slide under the microscope is very important in helping the veterinarian choose the right medication to treat the inflamed ear canal.

Performing ear cytology involves using a swab to obtain a sample of the debris in the infected ear. Once the sample is obtained, it is placed on a microscope slide and distributed evenly across the slide and then treated with special stains, each of which adheres to specific types of cells, organisms and/or parts of cells. The slide is then examined under a microscope under a high power, magnified by 10-40 times initially and then magnified by a higher factor, usually 100.

How are ear infections treated?

The results of the otoscopic examination and cytology tell us what to do.  If there is a foreign body or tick lodged in the ear canal, the dog is sedated so that it can be removed.  Some dogs have such a heavy buildup of debris that sedation is needed to cleanse the canal and examine it completely. 

Ear cytologic study of debris from the ear canal dictates which drug to use.  Sometimes, it reveals the presence of more than one type of infection (i.e., a bacterium and a fungus, or two kinds of bacteria); this situation usually requires the use of multiple medications or a broad-spectrum medication.

An important part of the evaluation of the patient is the identification of underlying disease.  Many dogs with chronic or recurrent ear infections have allergy
problems or low thyroid function (hypothyroidism).  If underlying disease is found, it must be diagnosed and treated, if at all possible.  If this cannot be done, the dog is less likely to have a favorable response to treatment.  Also, the dog might respond temporarily, but the infection will relapse at a later time (usually when ear medication is discontinued). 

What is the prognosis?

Nearly all ear infections that are properly diagnosed and treated can be cured.  However, if an underlying cause remains unidentified and untreated, the outcome will be less favorable.  A progress rechecks may be needed before the process is completed, but we expect ultimate success. 

How important is it to treat an ear infection?

Dogs with ear infections are miserable.  Their ears are a source of constant pain resulting in head shaking and scratching.  However, that is not the only problem.  Head shaking and scratching can also cause broken blood vessels in the ear flap, called an ear hematoma, which requires surgery, and chronic ear infections can penetrate the ear drum and result in an internal ear infection. 

My dog's ear canal is nearly closed.  Is that a problem?

Closing of the ear canal is another result of a chronic ear infection.  There are medications that can shrink the swollen tissues and open the canal in some dogs.  However, some cases will eventually require surgery.

What is the purpose of surgery?

The surgery for a closed ear canal is called a
lateral ear resection.  Its purposes are to remove the vertical part of the ear canal and to remove swollen tissue from the horizontal canal. 

What can be done if the ear canals are completely closed?

The most severe consequence of a chronic ear infection is total closure and hardening of the ear canal.  When this occurs, the lateral ear resection will no longer be helpful.  The appropriate surgery for this situation is an ear canal obliteration.  The total ear canal is surgically removed (TECA).  Since severe scarring and calcification occur, this can be a lengthy surgical procedure requiring a skilled veterinary surgeon.

Is there anything I need to know about getting medication in the ear?

It is important to get the medication into the horizontal part of the ear canal.  Be aware that the dog's external ear canal is "L" shaped.  The vertical canal connects with the outside of the ear; the horizontal canal lies deeper in the canal and terminates at the eardrum.  The ear canal may be medicated by following these steps:

1)  Gently pull the ear flap straight up and hold it with one hand.

2)  Apply a small amount of medication into the vertical part of the ear canal while continuing to keep the ear flap elevated.  Hold this position long enough for the medication to run down to the turn between the vertical and horizontal canal.

3)  Put one finger in front of and at the base of the ear flap, and put your thumb behind and at the base.

4)  Massage the ear canal between your finger and thumb.  A squishing sound tells you that the medication has gone into the horizontal canal.

5)  Release the ear and let your dog shake its head.  If the medication contains a wax solvent, debris will be dissolved so it can be shaken out. 

6)  If another medication is to be used, apply it in the same manner.

7)  When all medications have been applied, clean the outer part of the ear canal and the inside of the ear flap with a cotton ball. Do not use cotton tipped applicators to do this as they tend to push debris back into the vertical ear canal.

How to clean ears at home?

  • Your pet has been diagnosed with an ear infection. Proper ear cleaning is an extremely important step in management of infection in the external ear canal.

  • Ear cleaning may be required every day or less frequently depending on the debris present in the ear canal.

  • Ear cleaning solution should always be used as advised before any medication in the ear.


Follow these steps for cleaning your pet’s ears:


1.     Grasp the top of the ear and pull it straight up and slightly away from the head.

2.     Fill up the canal with ear cleaning solution until the liquid starts to spill out of the canal.

3.     Massage the base of the ear gently. You will hear a “squish” in the ear. Continue to massage for about a minute.

4.     Remove debris within the ear canal with cotton balls/tissue paper. Do not use Q-tips as this will push the debris further into the ear and could possibly cause damage to the ear canal.

5.     Let your pet shake his/her head.

6.     Ear medication should be placed 20-30 minutes after the cleaning procedure.

7.     Place the recommended amount of ear medication into the ears as per label directions and gently massage the ear to allow the medication to spread and penetrate.

  Improper cleaning will make the treatment of the ear infection less effective.

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