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. 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.
Normal cats seem very resistant to ear infections, especially when compared to dogs.
Finding otitis externa in a cat signals us 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. 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 a blood and urine sample from the cat.