Ear Infections in Cats (Otitis Externa)

How common are ear infections in cats?

Infections of the external ear canal or outer ear caused by bacteria and yeast are common in dogs but not as common in cats. Outer ear infections are called otitis externa. The most common cause of feline otitis externa is ear mite infestation.

What are the symptoms of an ear infection?

Ear infections cause pain and discomfort and the ear canals are sensitive. Many cats will shake their head and scratch their ears attempting to remove the debris and fluid from the ear canal. The ears often become red and inflamed and may develop an offensive odor. A black or yellow discharge is commonly observed.

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 in kittens and outdoor cats. Ear mites in adult cats occur most frequently after a kitten with ear mites is introduced into the household. Sometimes ear mites will create an environment within the ear canal that promotes the development a secondary infection with bacteria or yeast. 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, can I just buy some ear drops?

"Without knowing the kind of infection present, we do not know which drug to use."

No, careful diagnosis of the exact cause of the problem is necessary to enable selection of appropriate treatment. Several kinds of bacteria and fungi may also cause an ear infection. Without knowing the kind of infection present, we do not know which drug to use. In some cases a foreign body, tumor or polyp in the ear canal may cause the ear infection. Treatment with medication alone will not resolve these problems. It is important that the cat 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.

How do you find out what is causing the ear problem?

The veterinarian may examine the ear canal with an otoscope, an instrument that provides magnification and light. This gives a good view of the ear canal and allows the veterinarian to determine whether the eardrum is intact and if there is a tumor or foreign material in the ear canal. If there is a great deal of debris, discharge or inflammation within the ear canal, it may not be possible to perform a detailed examination. If this is the case, of if the ears are extremely painful and the cat refuses to allow ear examination, sedation or general anesthesia may be necessary.

The veterinarian may examine a sample of the material from the ear canal under the microscope. This is called ear cytology and is very important in helping the veterinarian choose the proper medication for your cat.

How are ear infections treated?

The results of the otoscopic examination and cytology tell the veterinarian how to properly treat your cat. If there is a foreign body lodged in the ear canal, the cat can be sedated so that it can be removed. Specific medication can be prescribed for bacteria or fungi; sometimes more than one type of infection is identified and this situation requires the use of multiple medications.

An important part of the evaluation is the identification of underlying disease. If this cannot be done, the cat is less likely to have a positive response to treatment; the cat may respond temporarily but relapse when the medication is discontinued.

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

"Normal cats are very resistant to ear infections."

Normal cats are very resistant to ear infections. Therefore, if a cat develops otitis externa, and especially if it recurs, it is necessary to look for an underlying cause such as an ear mite infestation, an unusual shape of the ear canal or a disease affecting the cat's immune system.

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.

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

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

How should I apply medication to my cat's ear?

• It is important to get the medication into the horizontal ear canal or lower part of the ear canal. The cat's ear canal is shaped like an "L" and you must ensure that you apply the medication into the entire ear canal. For step-by-step instructions, see our handout, Administering Ear Drops to Your Cat.

• When all ear 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, as they tend to push debris back into the vertical ear canal.