Feline: Ear Infection
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 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 carrying mites is introduced into the household or if they have encountered a cat with ear mites. Sometimes ear mites will create an environment within the ear canal which leads to 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?
No, careful diagnosis of the exact cause of the problem is necessary to enable selection of appropriate treatment. There are several kinds of bacteria and fungi that may also 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, tumor or polyp in the ear canal. 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 permits 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. When the ears are extremely painful and the cat refuses to allow ear examination, sedation or general anesthesia may be necessary.
The veterinarian may also 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. Some cats have such a heavy build-up of debris that sedation is needed to cleanse the canal and examine it completely.
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 of the cat 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.