The tubular portion of the outer ear that carries sound to the eardrum is called the ear canal. The most common disorder of the ear canal in cats is called otitis externa. This condition occurs when the layer of cells that line the external ear canal becomes inflamed. Signs include redness of the skin, swelling, itchiness, increased discharge, and scaly skin. The ear canal may be painful or itchy depending on the cause or duration of the condition.
Otitis externa can be caused by many different factors. Some of these factors (such as parasites, foreign objects, and allergies) appear to directly cause the inflammation, while others (such as certain bacteria and yeasts) worsen and perpetuate the condition. Identifying these factors is key to successful control of the inflammation. Unless all the causes are identified and treated, the condition may return. Thus, in addition to a physical examination, your veterinarian will ask about your pet's environment and exposure to chemicals and irritants.
The diagnosis, treatment, and preventive care for otitis externa in cats is very similar to this condition in dogs (see Ear Disorders of Dogs: Otitis Externa in Dogs).
Last full review/revision July 2011 by T. Mark Neer, DVM, DACVIM; Michele R. Rosenbaum, VMD, DACVD; Patricia D. White, DVM, MS, DACVD