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How to identify it
- Adults are barely visible to the naked eye: females are about 0.5 by 0.3 millimeter and males about 0.4 by 0.3 millimeter. Under magnification the adults show four pairs of long legs.[1]
- The ear canal fills with waxy or crusty debris, usually dark brown and often likened to coffee grounds, sometimes with blood.[1][2]
- Infested pets scratch and rub at their ears and shake their heads. Signs vary a lot: some cats with heavy discharge hardly itch, some dogs with little visible change itch intensely, and some animals show few or no signs at all.[1][2]
- They are confirmed by spotting mites in the ear canal with an otoscope or by finding mites in ear swabs or debris examined under a microscope.[1]
Look-alikes
| Look-alike | How to tell them apart |
|---|---|
| Flea bite allergy | Ear mites that leave the ears for the neck, rump and tail can cause skin lesions similar to flea bite allergic dermatitis. Finding the mites, in the ear canal or in ear swabs under a microscope, points to ear mites.[1] |
Where it lives
Ear mites infest dogs and cats worldwide and are commonly diagnosed during routine veterinary exams. They also live on a variety of wild carnivores, and ferrets and foxes are among their other hosts.[1][2]
Biology and life cycle
The whole life cycle takes place on the host, mainly on the skin surface of the outer ear canal. Females cement their eggs to hairs or skin, a six-legged larva hatches, and it molts through two eight-legged nymph stages to the adult in about three weeks. Adults are thought to live up to about eight weeks.[1][2]
They do not burrow. They feed on shed skin cells, ear secretions and tissue fluid, and the animal's immune reaction to the mites can make the irritation worse.[1][2]
Most often they pass from an infested mother to her puppies or kittens. They also spread by direct contact and on shared bedding, combs, brushes and other grooming gear. Off the host most mites last only a few days, but they can survive for months in cool, damp conditions.[1][2]
Young animals are affected more often than older ones, especially kittens 3 to 6 months old, possibly because older animals build up immunity. Infestations move quickly through groups of dogs or cats that are young, stressed or have weakened immune systems.[2][1]
Damage and signs
- The itch can be intense. Scratching, rubbing and head shaking can injure the ear flap and the lining of the ear canal and can lead to bleeding and aural hematomas.[1][2]
- Secondary bacterial infection can follow, sometimes producing a pus-filled ear infection.[1][2]
- Mites that wander out of the ears can cause crusty, bumpy skin lesions on the head, neck, feet, rump and tip of the tail. Signs sometimes include severe behavior changes and seizures.[1][2]
- Ear mites are estimated to cause up to 85 percent of outer ear inflammation (otitis externa) cases in cats and up to 50 percent in dogs.[2]
Health risk
People are rarely affected. Ear mites have been established in human ears in experiments, and Parasites & Vectors notes that humans are occasionally infested, but the University of Saskatchewan describes natural infestation of people as probably very rare and short-lived.[1][2]
Control
Sanitation
Treat every dog and cat in contact with the infested pet, since mites spread quickly and some carriers show few or no signs. Clean thoroughly or throw out bedding, and clean combs, brushes and other grooming tools that can carry mites.[1][2]
Pesticides
In a controlled study of experimentally infested animals, a single dose of fluralaner, an isoxazoline, given on the skin of cats or by mouth or on the skin of dogs, reduced mite counts by 100 percent in cats and 99.8 percent in dogs after 28 days.[2]
When to call a professional
Treatment products include selamectin, moxidectin combined with imidacloprid, milbemycin and ivermectin, along with newer isoxazolines given by mouth or on the skin; some of these are used off label. Treatments that work through the whole body are preferred over treating only the ears, because mites can live elsewhere on the body.[1]
Not all products kill the eggs, so products with lasting activity are preferred; otherwise a second treatment after three weeks may be needed to catch mites that hatch in the meantime.[1]
Gentle but thorough ear cleaning, medication to ease the itch, and antibiotics for any secondary bacterial infection also help.[1]
Common questions
- What does ear mite debris look like?
- It is waxy or crusty material in the ear canal, usually dark brown and often compared to coffee grounds, sometimes mixed with blood.[1][2]
- Can people catch ear mites from a cat or dog?
- Rarely. Ear mites have been established in human ears in experiments, but natural infestation of people is probably very rare and short-lived.[1]
- Why does every pet in the house need treatment for ear mites?
- Ear mites spread quickly through direct contact and shared bedding or grooming tools, and some infested dogs and cats show few or no signs, which is why all in-contact dogs and cats should be treated.[1][2]
Sources
- University of Saskatchewan, Western College of Veterinary Medicine, “Otodectes cynotis (Learn About Parasites).” wcvm.usask.ca/learnaboutparasites/parasites/otodectes-cynotis.php (accessed 2026-11-08)
- Parasites & Vectors (BioMed Central), “Efficacy of fluralaner against Otodectes cynotis infestations in dogs and cats (J. Taenzler and colleagues, published 16 January 2017).” parasitesandvectors.biomedcentral.com/articles/10.1186/s13071-016-1954-y (accessed 2026-11-08)
- iNaturalist, “Otodectes cynotis taxon page (order and family).” www.inaturalist.org/taxa/262955 (accessed 2026-11-08)