Ear Mites (Otodectes cynotis)

A common cause of itchy ears in dogs and cats are creepy, crawly ear mites! We get several questions about ear mites, like “what are they?” and “how did my pet get them?” Here are some answers to many of your questions. Keep in mind that there are several other common causes to itchy, irritated ears (such as bacteria, yeast infections, ear ticks). It is always best to have a veterinarian look in your animal’s ears to make the correct diagnosis, so that your pet may get an appropriate treatment.

What are ear mites?
Ear mites are very small organisms that are nearly impossible to see with the naked eye. Under the microscope, they look similar to a tick. An adult ear mite lives about 2 months. Ear mites feed on ear wax and skin oils. They lay eggs, which take 4 days to hatch out and 3 weeks to develop into adults. Ear mites produce a characteristic black, crusty discharge deep in the ear canal. That black, crusty discharge is made up of dried blood, ear wax, inflammatory chemicals and the mites themselves.

Interesting (and Bizarre!) Ear Mite Fact:
After hatching out of an egg, an ear mite larva molts several times. The last stage before adulthood is called a deutonymph. A deutonymph does not yet have a determined gender, yet it mates with an adult male ear mite. After mating, the deutonymph will molt into either a female or a male. If it turns out to be a female mite, it will then lay eggs. If it turns out to be a male mite, there are no consequences to it having mated, and it then goes on to mate with more deutonymphs!

How did my pet get ear mites?
Most ear mites are found in cats, but they can also be found in dogs. Pets get them from direct contact with other animals or from sharing a bed with other animals. Ear mites are easily transmitted from one animal to another, so it is important to treat all animals in a household. If one pet has mites, chances are that the others do, too.

What happens if my animal has ear mites?
The main thing that happens is intense itchiness! They will also get a secondary ear infection if left untreated. This can lead to an ear hematoma, which may have to be fixed surgically. Sometimes, ear mites can also live outside of the ear canal and cause skin problems, especially on the face.

Can humans get ear mites?
While it is possible for humans to acquire ear mites, it is extremely unlikely. One veterinarian infected himself on purpose and was eventually successful, but only after several purposeful attempts.

How do you treat for ear mites?
As mentioned above, make sure to treat all animals at home. Make sure to also wash any bedding that they sleep on. The following are the various treatment methods, with the “single use products” being the easiest and most effective. If ear mites are a major problem in your neighborhood or if you have several stray cats, then a monthly prevention may also be needed to help control them.

Single Use Products: Acarexx and Milbemite are two prescription products that kill both the adult mites and their eggs, making them single treatment products. They are applied to the ear canals.
Topical Over-the-Counter Treatments: There are several ear mite products available, including over-the-counter medications. The problem with the over-the-counter medications is that they must be used for 21-30 days, because they do not kill the mite eggs. If they are stopped too early, the mite eggs will hatch out, and the ear mites will persist.

Ivermectin Injections- 2-4 Treatments: This can be a highly effective method of killing ear mites; however, it is risky to certain breeds of dogs (especially Collie breeds), as it is a high dose of Ivermectin. It is not approved for the treatment of ear mites in small animals, because it has the potential to cause neurologic side effects and because there are safer alternatives.

Monthly Topical Preventions: The monthly flea & heartworm preventions Revolution and Advantage Multi help control ear mites. While they will not completely treat an ear mite infection, they are good products to help decrease the ear mite population and prevent future recurrences.

While ear mites are a common parasite of the ears, we recommend not trying to make the diagnosis at home. There are several other causes of ear irritation, and each requires a specific treatment. If you have an animal with ear issues, be sure to have it looked at by your vet, so your pet can get the appropriate relief that they need.

By: Ryan Roberts
Source: “Ear Mites FAQ”, The Pet Health Library, Dr. Wendy Brooks, DVM