A close-up of an ear mite. Photo courtesy Dr. Teri Ann Oursler

Most people have heard of ear mites and know they are a common ear parasite of dogs and cats, but that is where most people's knowledge of ear disease ends. In fact, inflamed ears have many potential causes, and assuming the problem is an ear mite infection can lead to weeks of the wrong treatment. Furthermore, there are many treatments for ear mites, and it is important to know that ear mite elimination no longer requires weeks of labor-intensive, uncomfortable, oily topical therapy are no longer necessary. 

What are Ear Mites?

Ear mites are tiny infectious organisms resembling microscopic ticks. The mite can just barely be seen by the naked eye as a small white dot, though. Ordinarily, it is necessary to look at an ear wax sample under the microscope to see it. Infection usually produces a characteristic dry black ear discharge that is commonly said to resemble coffee grounds. This discharge is composed of ear wax, blood, inflammatory biochemicals, and the ear mites themselves. Because the discharge is so classic in appearance, a diagnosis of ear mite infection is often made based on its presence. This leads to the potential to be led astray. It is best to examine the material under the microscope and confirm the mites so that proper treatment can be instituted.

The Bizarre Ear Mite Life Cycle

The mite lives on the surface of the ear canal skin, though sometimes migrates out onto the face and head of its host. Eggs are laid and hatch after 4 days of incubation. The larva hatches from the egg, feeds on ear wax and skin oils for about a week, and then molts into a protonymph, which in turn molts into a deutonymph. The deutonymph mates with the adult male. What seems especially bizarre to us mammals is that the deutonymph has not yet developed a gender at the time it mates with the adult male.

After mating, the deutonymph molts into either an adult male or an adult female. If it becomes a female, she will be gravid with eggs as a result of the mating. If it develops into a male, there are no consequences to the mating and he is ready to mate with deutonymphs of his own choosing. The adult mite lives approximately two months happily eating ear wax and skin oils. The life cycle - the time it takes for an egg to develop into an adult mite ready for parenthood - requires three weeks.

Most ear mite cases are found in cats. Dogs can be infected as well but, since dogs more commonly get ear infections of other types, ear infections in dogs usually do not involve mites.

How did my Pet get Ear Mites?

Ear mites readily transmit from host to host by physical contact. Ear mites came from some other animal with which your pet was socializing. Because mites can be transmitted easily by physical contact, treating mites must include all household pets. Dogs and cats spread mites readily to one another by physical contact.

What Harm Comes from Ear Mite Infection?

Ear mites are inflammatory and they can generate very irritating ear infections. Skin disease can also result from ear mite infection.

Is this Contagious to Me?

Ear mite infection is certainly contagious among cats and dogs. Typically, the victim is an outdoor cat. Humans have been reported to develop skin rashes rarely; in general,  it may be considered that humans are extremely unlikely to experience any symptoms when their pet is infected with ear mites.

Treatments

Topical Treatments: at Least Three Weeks Usage
Most older and over-the-counter products contain insecticides that do not kill developing mite eggs. Because of this limitation, such products must be used for at least the duration of the 21-day life cycle. Some specialists recommend a 30-day treatment course with such products. While these products do work and are readily available at most pet supply stores, three weeks of use is relatively inconvenient and the pet may not always be cooperative.

Topical Treatments: at Least Ten Days Usage
Another approach involves the use of a prescription topical ear medication called Tresaderm® which contains an antibiotic for any secondary bacterial infections, a steroid for inflammation, and thiabendazole to kill yeasts and mites. This product is excellent for ears and is able to kill the developing mite eggs. This cuts the treatment course down to 10 to 14 days and provides an excellent oily lubricant with which to clean the ears. This product has been favored by veterinarians for decades; still, it is no longer state of the art.

Injection: Two to Four Treatments
An older and not FDA-approved treatment involves the use of ivermectin, a powerful antiparasitic medication. It is rarely used for ear mites as there are many FDA-approved products nowadays but in certain circumstances, it might be a good choice. Most ivermectin injectable protocols involve shots weekly or every two weeks. This is a highly effective method of ear mite eradication but there are some limitations. Certain breeds of dogs are sensitive to this medication and cannot take it. Certain individuals have similar sensitivities which cannot be predicted by breed. Injectable ivermectin is not approved for the treatment of ear mites in small animals. For safety reasons, it is better to employ one of the single-use products approved for use against ear mites.

Single Use and Other Prescription Treatments
Several prescription products are currently available that reliably eradicate an ear mite infection with one single use, though a thorough ear cleaning is still needed to remove the wax and debris from the ear. These products may be applied directly in the ear, behind the shoulders, by injection, or orally. 

There is presently only one single-dose topical product: Milbemite®, a topical version of milbemycin oxime. This product is approved for cats only and is available only through veterinarians. A single dose should be all that is needed to clear the infection.

As for topical products that go behind the pet's shoulders, many parasite-control products can be used. Active ingredients such as selamectin, moxidectin, fluralaner, and saralaner. These products absorb through the skin and into the body, where they re-emerge in the skin and ear secretions consumed by the mite. Mites are readily killed off by these treatments and if they are used regularly, new ear mite infection is prevented. These products also kill fleas and sometimes ticks and intestinal worms, depending on their formulation. They are designed for ongoing use to control parasites. All of these products require a prescription, which means a veterinary visit is needed to get them.

Both selamectin and moxidectin are ivermectin derivatives, while fluralaner is of the new isoxazoline class. These three products are absorbed into the body where they kill numerous other parasites and then are concentrated in the skin. When these products are used as regular flea control, they have the added benefit of ongoing ear mite prevention. All three products are available only through veterinarians. In some cases, a final ear cleaning is needed a month or so after the product has been applied to remove any dried or old ear wax still left in the ear. 

In dogs, there are presently four isoxazoline products available for oral use: Simparica® (sarolaner), Nexgard® (afoxalaner), Bravecto® (fluralaner), and Credelio®(lotilaner).

For cats, there is an oral formula of Credelio® (lotilaner). 

What If They Are Hard To Treat?

Occasionally, a cat may have a case of ear mites for which “everything” has been used, and the mites simply will not go away. In this situation, consider:

1. Was the mite infection confirmed initially? Remember, it is easy to be fooled by a discharge that appears typical of mites. This might not be an ear mite infection at all, or perhaps it was in the beginning but is now a bacterial or fungal infection.
   
   
2. Has the continuing mite infection been confirmed after treatment? Sometimes, a telltale hard bit of ear wax must be removed from the ear before comfort is finally achieved. Sometimes, a bacterial infection remains, though the mites are long gone. Treating for ear mites when there aren't any will not achieve results.
   
   
3. Were all the hosts in the family treated? If all pets were not treated, begin again, this time including all pets in the protocol. If all pets are not treated, they will simply re-infect each other.
   
   
4. Consider using one of the new products. If you are trying to use one of the daily products, it is easy to skip a day here and there.