Cats – Ear Infections

FACTSHEET

How common are ear infections (otitis) in cats?

Infections of the external ear canal (outer ear) by bacteria or yeast are common in dogs, but not very common in cats. We call this otitis externa. The Persian and Himalayan breeds appear more prone to ear infections than other breeds of cats.

What are the symptoms of an ear infection?

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

Don't these symptoms usually suggest ear mites?

Ear mites can cause several of these symptoms, including a black discharge, scratching, and head shaking. However, ear mite infections generally occur most commonly in kittens. Ear mites in adult cats occur most frequently after a kitten 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 cat is presented to the veterinarian, the mites may be gone, but a significant ear infection remains.

Since these symptoms are similar and usually mean an infection, can I just buy some medication without an examination for my cat?

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, your veterinarian will 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. Treatment with medication alone will not resolve these problems. Also, the cat 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 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 your veterinarian to determine whether the eardrum is intact and if there is any foreign material in the canal. When the ears are extremely painful and the cat refuses to allow ear examination, sedation or general anesthesia may be necessary.

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 cytology. Examination of that material under the microscope is helpful to the veterinarian to choose the right medication to treat the inflamed ear canal.

How are ear infections treated?

The results of the otoscopic examination and cytology tell your veterinarian what to do. If there is a foreign body or tick lodged in the ear canal, the cat is sedated so that it can be removed. As stated previously, some cats have such a heavy buildup of debris that sedation is needed to cleanse the canal and examine it completely. 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 (that is, a bacterium and a fungus, or two kinds of bacteria). This situation usually requires the use of multiple medications.

An important part of the evaluation of the patient is the identification of underlying disease. If underlying disease is found, it must be diagnosed and treated, if at all possible. If this cannot be done, the cat is less likely to have a favorable response to treatment. Also, the cat might respond temporarily, but the infection will relapse at a later time (usually when medication is discontinued).

Since ear infections are uncommon in cats, should I be concerned that something else is going on?

Normal cats seem very resistant to ear infections, especially when compared to dogs. Therefore, finding otitis externa in a cat is a signal to look for an unusual shape of the ear canal or for something that could affect the cat's immune system.

There are two viruses that can cause immune system suppression. Cats with ear infections which cannot be explained should be tested for these two viruses: the feline leukemia virus and the feline immunodeficiency virus (sometimes called the feline AIDS virus). A small amount of blood is needed to test for these viruses. Diabetic cats are also known to have more frequent ear infections than other cats. The diagnosis of diabetes mellitus can be made with blood and urine tests.

 

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What is the prognosis?

In the cat, 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 check may be needed before the process is completed, but ultimate success is expected. However, the presence of one of the immune suppressing viruses will complicate treatment and will have long term implications on the general health of the cat.

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

Closing of the ear canal occurs when an infection becomes very chronic. There are medications that can shrink the swollen tissues and open the canal in some cats. However, some cases may eventually require surgery.

What is the purpose of the 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. Removing the vertical canal should be successful, but removal of large amounts of tissue from the horizontal canal is more difficult. In some cases, the ear canal is surgically obliterated. This solves the canal problem, but it leaves the cat deaf on that side.

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

A cat's ear canal makes a right angle before coming to the ear drum versus a person's ear canal which is straight. Therefore you can gently insert a Q-tip or tip of a tube into a cat's ear canal without being near his or her ear drum.

It is important to get the medication into the horizontal part of the ear canal. This is best done 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 cat shake her 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 soaked with a small amount of rubbing (isopropyl) alcohol.

The cat may shake her head or scratch at her ears after cleaning and treating the ears. This is a normal response.