Otitis externa is a term used to describe an inflammation of the external ear (outside of the ear drum).
Otitis externa has many causes, but the signs are usually the same. Head shaking and scratching at the ears are probably the most common. In some cases the cat will tilt the head slightly toward the side of the irritated ear; touching the ear may cause signs of pain. Large amounts of waxy discharge are often present; in severe cases there may be actual pus. the inside of the pinna is sometimes abnormally pink, and there may be swelling. The normal of a healthy cat ear becomes fetid as the inflammation gets worse. The most common cause of otitis externa of cats are mites. If you cannot be sure that ear inflammation in your cat is caused by mites or if you are not sure you can treat the problem at home, visit your veterianrian. Ear inflammation not treated promptly and vigorously can result in ear conditions that are difficult to treat. The infection can progress to include the middle and inner ear.
A yeast, Malassezia pachydermatis is found in as many as one-third of cat ear infections. Signs of discomfort that may range from mild to severe are often associated with a brown, waxy discharge when excessive numbers of these organisms are present. Usually an increase in ear scratching is seen. This yeast thrives in a warm, moist environment. A microscopic examination of debris associated with this type of ear inflammation is needed to be sure the yeast is present. Ears that are kept dry, clean, and slightly acid in pH are less likely to develop excessive numbers of yeast; so predisposed cats often need a routine of home care to prevent repetitive problems. Commercial products containing alcohol and boric acid, instilled into the ears once or twice a week, can prevent yeast-associated otitis externa. The skin of cat's ears may be damaged by sun exposure.