Ear Mites in Cats and Dogs

What are ear mites?

The ear mite, Otodectes cynotis, is a surface mite that lives on cats, dogs, rabbits, and ferrets. It is usually found in the ear canal but it can also live on the skin surface. Ear mites are highly contagious, and animals become infested by direct contact with another infested animal. The mite is barely visible to the naked eye and may be seen as a white speck moving against a dark background.

What is the life cycle of the ear mite?

It takes approximately 3 weeks for a mite to develop from an egg to an adult, going through a total of 5 stages. Adult ear mites live about 2 months, during which time they continually reproduce. The entire ear mite life cycle takes place on the host animal, although mites can survive for a limited time in the environment.

What are the clinical signs of ear mites?

Ear mites are a common cause of ear disease and infection, although other ear conditions may cause similar clinical signs. They are the second most common ectoparasite (external parasite) found on pets; the most common is the flea.

Infestations are a very common problem in puppies and kittens, although pets of any age can be affected. Clinical signs of infestation vary in severity from one pet to another, and may include combinations of:

1. Ear irritation, leading to scratching at the ears or head shaking.

2. A dark waxy or crusty discharge from the ear.

3. Areas of hair loss resulting from self-trauma caused by the dog’s scratching or excessive grooming.

4. A crusted rash around or in the ear.

5. An aural hematoma (a large blood blister on the ear, caused by rupture of small blood vessels between the skin and cartilage); this occurs due to the dog scratching at their ears.

Skin lesions most frequently affect the ear and surrounding skin but occasionally other areas of the body may be affected.

How are ear mite infestations diagnosed?

Typical clinical signs with a history of contact with other cats or dogs would suggest the involvement of ear mites. Although ear mites frequently cause ear disease, other conditions can result in very similar clinical signs and must be ruled-out before treatment is begun.

A diagnosis is made by observing the mite. This is usually straightforward and may be done either by examination of the pet's ears with an otoscope or by microscopic examination of discharge from the ear. If the ears are very sore, the pet may need to be sedated to allow the ears to be properly examined and treated.

How are ear mites treated?

Your veterinarian will advise you about which insecticidal products are suitable. There are several ear medications licensed for the treatment of ear mites in pets. No medication can penetrate the eggs or pupae, so treatment is directed at killing the adult and larval forms.

A variety of different treatment options are available to your veterinarian. Some are daily topical medications, while others may be injections (e.g., ivermectin), or single-use products such as Milbemite®, Revolution®, Advantage Multi®, Simparica® or Bravecto®. Your veterinarian will determine what the most appropriate treatment may be given the situation and your preferences.

There are no products licensed for use in the house or on an animal's skin, but many products licensed for flea control are effective.

Your veterinarian may want to re-examine your pet to ensure that the mites have been eliminated after the initial treatment has been performed.

Do ear mites affect people?

Ear mites may cause a temporary itchy rash on susceptible people if there are infested pets in the household, although this is considered to be a rare event. Eradication of the mites from the pets will cure the problem.