Monday, October 22, 2012

Ear Mites

Ear mite

General Information

Ear mites which are microscopic organisms that look kind of like clear ticks when viewed under a microscope. Ear mites commonly cause problems in young, outdoor/stray animals and are not as commonly seen in mostly indoor pets. There is, unfortunately, a tendency for people to see a pet's inflamed ear with discharge and assume it is an ear mite infection. This leads to weeks of inappropriate treatment with over-the-counter remedies while the infection gets worse. It is important to distinguish an ear infected with yeast or bacteria (the more common cause) from one infected with mites.

The mite lives on the surface of the ear canal skin, although it sometimes migrates out onto the face and head of its host. Eggs are laid and after 4 days of incubation they hatch. Then the larvae take approximately three weeks to mature into adult mites. The adult mite can live for two months. They feed off the ear wax and skin oils found in the ear canals. Ear mites readily transmit from host to host by physical contact.

Clinical Signs

Typical appearance of ear cerumen in a cat with ear mites. Ear mite infections often produce a characteristically dry black ear discharge, said to resemble coffee grounds. Because of the classical appearance of this discharge, infection is often diagnosed based on this discharge alone, although without visual confirmation of the mite under the microscope, it is possible to be led astray. The discharge is composed of ear wax, blood, inflammatory biochemicals, and the ear mites themselves. The dog or cat may have red swollen ears and frequently scratch or shake their head. Secondary complications include yeast or bacterial ear infection and an aural hematoma.

Diagnosis

If you have good vision ear mites can just barely been seen with the naked eye as a small white speck in the ear wax, but most often the diagnosis has to be made by taking a sample of ear wax and looking at it under the microscope.

Treatment

  • The old topical remedies requiring several weeks of ear cleaning and treatment have largely been replaced by far simpler products. These older treatments, that are still available over the counter, contain insecticides that did not kill off the mite eggs so a minimum of three weeks of treatment was required to break the life cycle. Because mites are so easily transmitted by physical contact, often all household pets will require treatment.
  • Prescription topical ear medication called Tresaderm® contains an antibiotic for any secondary bacterial infections, a cortisone derivative for the inflammation, and thiabendazole to kill yeasts and mites. This is an excellent ear product that is able to kill the developing mite eggs as well as treat secondary infections. Treatment with Tresaderm® typically lasts 10-14 days.
  • Today we have the ability to treat uncomplicated ear mite infections with a single dose of medication. There are currently two current products available that are applied directly into a cat's ear canal. Acarexx®, a topical version of ivermectin (the active ingredient in Heartgard®) and Milbemite®, a topical version of milbemycin oxime (active ingredient in Interceptor®). These products are only approved for use in cats in the USA and are only available only through veterinarians. A prescription is required so any website that says otherwise should not be trusted.
  • There are also products available on the market to prevent ear mite infections. These are most beneficial for use on cats that commonly go outdoors and may interact with other outdoor animals. Revolution®, which uses selamectin as an active ingredient, and Advantage Multi®, which uses moxidectin as an active ingredient, are monthly topical medications commonly used for flea control, heartworm prevention as well intestinal parasite prevention. protection.