Q. Earmites seem to be present in almost all cats. How serious a problem are they and how can the mites be dealt with?

The mites feed on epidermal debris - bits of dead skin shed into the ear canal. Unlike in dogs which show signs of severe irritation early on following infection, cats are often at an advanced stage before clinical signs are evident. The mites lay single eggs which develop into adults in just three weeks. The clinical signs include shaking of the head, scratching at the head and neck, and on examination the ears are found to contain a dry, waxy brown debris in which the mites are living and feeding. It is a very commonplace infection and is very easily spread by contact between mother and kittens and between adults sharing the same household. 

Whereas many cats tolerate the presence of the mites up to an advanced stage of infection, they will eventually succumb to the fairly serious outcome of chronic aural irritation. Constant shaking of the head can lead to aural haematomas - bleeding from a blood vessel into the ear flap which requires surgical correction. Secondary bacterial infections may develop leading to an inflammation of the ear with the presence of pus which may in turn lead to the rupture of the tympanic membrane or ear drum which can lead to a much more serious middle or inne ear infection with possible loss of balance and deafness. 

It is therefore important to treat all ear mite infestations as early and as thoroughly as possible. It is essential that your vet cleans out all the wax and debris from the affected ear to allow the medication access to the whole ear canal. An insectidal liquid is then instilled into both ear canals on a daily basis. It is most important that treatment includes all animals in the household and that it is continued for three to four weeks as eggs present in the ear will not be killed by the drops. If these eggs hatch out after treatment has stopped, the infestation will start all over again.