Dog: Ear Mites

General information

Other common/scientific names: Otodectes cynotis

Ear mites are common parasites that live in the ear canal of dogs. They are more commonly seen in cats and young puppies but can infest adult dogs with weakened immune systems. Ear mites cause inflammation by eating ear wax and skin oils. Secondary infections can result from ear mites causing mild to severe otitis.


Otodectes cynotis is the ear mite that infests both dogs and cats. The adult mite spends its entire life on the host and lives in the ear canal; although they can migrate onto the head and face of the dog. Female mites lay eggs which hatch after a four day incubation period. Eggs mature into larvae then nymphs then adults. This life cycle requires three weeks for eggs to reach adult stage.


Ear mites are contagious among dogs and cats and are transmitted from animal to animal by direct contact. The most common source of ear mites is an outdoor cat.

Cardinal symptom

Scratching at ears


Ear mites cause itchiness resulting in scratching at the ears and head shaking. A dry, black discharge resembling coffee grounds is commonly seen in the ear canals. Redness, pain, scabs and bleeding can result from the ear mites and self trauma.


Diagnosis of ear mites is made by physical examination and an ear swab. A sample of the discharge is taken from the ear using a cotton swab. This sample is mixed with mineral oil and examined using a microscope. The ear mites and ear mite eggs are readily identified.

Abb. GG0JY4EX: Ear mite.
This is a photograph of an adult ear mite as seen under a microscope.
Abb. GG0JZ9DT: Ear mite eggs.
This is a photograph of several ear mites eggs (oval, gray structures) as seen under a microscope.


Ear mites should only be treated after a veterinarian has made the diagnosis. The first step to treatment involves cleaning the ear. Moderate to severe infestations may require sedation and flushing.

There are several products used to treat ear mites. Most older and over-the counter (OTC)products do not kill the mite eggs. These products must be used for at least 21 days-the duration of the life cycle. Prescription medications that are applied directly to the ear are used as single use and multi-use treatments. However, the newer topical or spot-on products are used most commonly to treat ear mites. These insecticides are applied to the skin between the dog’s shoulders. One treatment can result in a cure. Other dogs may need repeat dosing. Dogs diagnosed with ear mites should be re-examined after 3-4 weeks. Because of the contagious nature of ear mites, all pets in the household should be treated.


Most dogs respond well to ear mite treatment. Chronic, untreated ear mite infestation can lead to chronic ear infections.


Ear mites can be prevented by monthly application of the topical (spot-on) products that are used for treatment. These monthly applications are also used to prevent tick, flea, mite, heartworm and endoparasite infections.


Dog owners should never diagnose an ear mite infection. Unfortunately, it is common for owners to see a dog’s inflamed ear and assume it is an ear mite infection. This can lead to weeks of inappropriate treatment with over-the-counter remedies. See your veterinarian at the first sign of ear disease.

Update version: 4/24/2014, © Copyright by
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