Ear Mites in Cats and Dogs: Identification and Treatment

Ear mites are tiny, spider-like parasites that live primarily in the ear canals of cats and dogs, feeding on ear wax, skin oils, and cellular debris. The species responsible for the vast majority of ear mite infestations in pets is Otodectes cynotis — a surface-dwelling mite that completes its entire three-week life cycle within the ear canal and on the surrounding skin. Despite their minuscule size (adult mites are only about 0.3 to 0.4 millimetres long, barely visible to the naked eye as tiny white moving specks), ear mites cause enormous discomfort and can lead to significant secondary complications if left untreated.

"Ear mites are one of the most common ectoparasites I see in feline practice, particularly in kittens and young cats. What many owners don't realise is just how contagious these mites are — if one cat in the household has ear mites, there is an extremely high probability that every other cat and dog in the home is also infested, even if they aren't showing obvious symptoms yet. This is why I always emphasise treating every pet in the household simultaneously, not just the one scratching its ears." — Dr. Sarah Chen, DVM

Ear mites are significantly more common in cats than in dogs, with studies suggesting they are responsible for approximately 50 per cent of all ear infections in cats compared to only 5 to 10 per cent in dogs. Kittens are particularly vulnerable because they acquire mites from their mother during the nursing period, when prolonged close contact facilitates easy transfer. Cats with outdoor access, those living in multi-cat households, and cats in shelters or catteries face the highest risk. While ear mites can affect dogs of all ages, puppies in close contact with infected cats or dogs are the most commonly affected canine group.

The life cycle of Otodectes cynotis takes approximately three weeks from egg to adult. Female mites lay eggs in the ear canal, which are cemented to the surface with a sticky secretion. The eggs hatch after about four days into larvae, which feed and moult through two nymphal stages before reaching adulthood. All mobile stages — larvae, nymphs, and adults — feed on the ear canal lining, causing irritation and triggering an inflammatory response. The resulting inflammation, combined with the physical presence of the mites and their waste products, stimulates excessive earwax production and creates the characteristic dark, crumbly discharge that is the hallmark of ear mite infestation. For a broader understanding of parasites that affect pets, our guide on common parasites in dogs and cats provides valuable context.

The symptoms of ear mite infestation are often dramatic and hard to miss, particularly in cats. The single most characteristic sign is intense, persistent itching of the ears, which manifests as frequent, vigorous head shaking and aggressive scratching at the ears with the hind paws. Affected cats and dogs may scratch so intensely that they cause self-inflicted wounds — scratches, scabs, and areas of hair loss around the ears, temples, and the back of the head. In severe cases, the repeated head shaking can even cause an aural haematoma, a painful swelling of the ear flap caused by the rupture of blood vessels within the pinna.

The most telltale clinical sign of ear mites is the distinctive ear discharge. Unlike the yellowish or greenish discharge typical of bacterial or yeast ear infections, ear mite discharge is characteristically dark brown to black in colour and has a dry, crumbly, granular texture that is universally described as resembling coffee grounds. This discharge is a combination of dried blood, ear wax, inflammatory debris, mite waste products, and the mites themselves. The volume of discharge can be remarkable — severely affected ears may be packed with this dark, crusty material, partially or completely occluding the ear canal. The discharge typically has a distinctive musty odour, though it is generally less pungent than the smell associated with bacterial ear infections.

Additional symptoms may include ear inflammation — the ear canals appear red, swollen, and irritated when examined — and the animal may show signs of pain when the ears are touched or manipulated. Some cats hold their ears in an abnormal, flattened position, and dogs may tilt their head to one side. In rare cases, ear mites can migrate out of the ear canal and onto the skin of the head, neck, and body, causing patchy dermatitis and itching in these areas. This is more commonly seen in cats and can be confusing diagnostically because the skin lesions may resemble other conditions such as allergic dermatitis or ringworm.

It is important to note that some animals, particularly adult cats with long-standing, low-level infestations, may show surprisingly subtle symptoms. They might exhibit only occasional ear scratching or mild head shaking that the owner attributes to normal behaviour. This is why veterinary examination is so valuable — your vet can detect mites even in animals that appear minimally affected, preventing the infestation from spreading to other pets in the household and potentially avoiding secondary complications. If your pet is showing signs of ear discomfort, understanding the difference between mites and infections is crucial — we explore ear infections in detail in our guide on ear infections in dogs.

Ear mites are highly contagious between animals, spreading primarily through direct, close physical contact. When cats groom each other, sleep curled up together, or simply spend time in close proximity, mites can easily crawl from one animal's ears to another's. This is why ear mites spread so efficiently within multi-pet households — the natural social behaviours of cats and dogs practically guarantee transmission. Kittens almost invariably acquire ear mites from their mother during the first few weeks of life, when the close physical contact of nursing and grooming provides continuous opportunities for mite transfer.

While direct contact is the primary transmission route, ear mites can also spread through shared bedding, blankets, and resting areas. Although Otodectes cynotis mites strongly prefer living on a host, they can survive in the environment for a limited period — generally a few days to a couple of weeks depending on temperature and humidity. This means that a mite that falls off an infected animal onto a shared cat bed, blanket, or sofa cushion can potentially crawl onto another pet that uses the same resting spot. Shared grooming tools, though less commonly implicated, could theoretically serve as a transmission route as well.

Cross-species transmission between cats and dogs is common and is an important consideration in households with both species. If your cat has ear mites, your dog is at risk, and vice versa. Ferrets are also susceptible to Otodectes cynotis and should be included in any household-wide treatment plan. Rabbits and other small mammals can potentially be affected, though their primary ear mite species differ. One reassuring fact for pet owners is that ear mites are not considered a significant zoonotic risk — they do not establish infestations on humans. In rare cases, people in close contact with heavily infested pets may experience transient, mild skin irritation on the arms or torso, but this resolves quickly once the pet is treated and the mites have no human host to sustain them.

The extremely contagious nature of ear mites has a critical practical implication for treatment: every cat, dog, and ferret in the household must be treated simultaneously, regardless of whether they are showing symptoms. Treating only the symptomatic animal while leaving other pets untreated creates a reservoir of mites that will simply re-infest the treated animal once the medication wears off. This is the single most common reason for apparent treatment failure — the medication worked perfectly, but the mites returned because an untreated housemate served as a continuous source of reinfestation.

Veterinary diagnosis of ear mites is usually rapid and straightforward, involving two complementary methods: otoscopic examination and microscopic examination of ear discharge. During an otoscopic examination, your veterinarian uses a handheld instrument called an otoscope to look directly into the ear canal with magnification and illumination. In many cases, the mites themselves can be seen moving within the ear canal — they appear as tiny white or translucent dots moving against the dark background of the ear discharge and canal wall. This direct visualisation is often sufficient for a confident diagnosis, particularly when combined with the characteristic dark, coffee-ground discharge.

For confirmation or when the otoscopic view is obscured by heavy discharge, your vet may take an ear swab — using a cotton-tipped applicator to collect a sample of the ear discharge — and examine it under a microscope. When the material is placed on a slide, mites, their eggs, and faecal pellets are readily visible at low magnification. The mites have a characteristic oval body shape with eight legs (in the adult stage), and the eggs are distinctively large and oval. This microscopic examination is quick, inexpensive, and highly reliable, providing a definitive diagnosis within minutes.

One situation where diagnosis can be more challenging is in animals that have been partially treated or that have very low-level infestations. In these cases, only a few mites may be present, making them harder to spot on otoscopic or microscopic examination. Your vet may need to examine the discharge sample more thoroughly or request a follow-up visit. Additionally, secondary bacterial or yeast infections can develop alongside the mite infestation, altering the appearance of the ear discharge and potentially masking the underlying mite problem. This is why a thorough ear examination by a veterinarian is always preferable to guessing at the diagnosis based on symptoms alone.

It is worth emphasising that not all dark ear discharge means ear mites, and not all itchy ears mean ear mites. Bacterial infections, yeast infections (particularly Malassezia), allergic ear disease, and foreign bodies can all produce similar symptoms. Self-diagnosing and treating with over-the-counter ear mite products when the actual problem is a bacterial infection can delay appropriate treatment and potentially worsen the condition. A veterinary examination costing a modest consultation fee provides a definitive answer and ensures your pet receives the correct treatment from the start.

Modern ear mite treatment has become remarkably effective and convenient, with several excellent options available depending on your veterinarian's preference, the severity of the infestation, and the species of pet being treated. The most important principle to understand before selecting a treatment is that all pets in the household — every cat, dog, and ferret — must be treated simultaneously. Treating only the symptomatic animal while leaving housemates untreated virtually guarantees reinfection and is the most common reason for treatment failure.

Topical spot-on treatments applied to the skin between the shoulder blades have revolutionised ear mite treatment by combining ease of application with excellent efficacy. Selamectin (marketed as Revolution or Stronghold) is applied once monthly and kills ear mites along with fleas, heartworm larvae, roundworms, and hookworms. A single application is often sufficient to clear an ear mite infestation, though many veterinarians recommend a second application one month later to catch any mites that hatched from eggs after the first treatment. Moxidectin combined with imidacloprid (Advocate or Advantage Multi) is another highly effective spot-on option. These products are particularly convenient because they treat the mites systemically — the active ingredient is absorbed into the bloodstream and kills mites when they feed — meaning you do not need to apply anything directly into potentially painful, inflamed ears.

Direct topical ear medications remain a valid treatment approach, particularly for targeted, rapid mite killing within the ear canal. Milbemycin-containing ear drops (such as MilbeMite) can be effective with a single application when applied by a veterinarian. Ivermectin-based ear drops, applied daily or every other day for two to four weeks, are another option, particularly in clinical settings treating large numbers of animals. Before applying any topical ear medication, the ears should ideally be cleaned to remove the heavy discharge that shelters and feeds the mites — your veterinarian can perform a thorough ear cleaning under gentle sedation if the ears are severely affected and painful.

In addition to treating the mites themselves, secondary infections must be addressed. Many animals with chronic ear mite infestations develop bacterial or yeast infections in the damaged, inflamed ear canals. Your vet may prescribe a combination ear medication that contains an antibiotic, an antifungal, and an anti-inflammatory alongside the miticide, or they may treat the secondary infection separately with targeted medications. Environmental cleaning — washing all pet bedding on a hot cycle, vacuuming soft furnishings, and disinfecting hard surfaces — helps remove any mites or eggs that have fallen off the pet and reduces the risk of reinfestation. With appropriate treatment of all household pets and basic environmental hygiene, ear mite infestations can be fully resolved within three to four weeks, and recurrence is uncommon as long as the household is not exposed to new untreated animals. For new kitten owners navigating these first health decisions, our new kitten checklist provides a comprehensive roadmap.

One of the most common mistakes pet owners make is assuming that any ear problem is caused by ear mites and reaching for over-the-counter mite treatments without a veterinary diagnosis. While the impulse to help your pet quickly is understandable, treating an ear infection with a mite-only product — or treating mites with an antibacterial product — wastes time, money, and prolongs your pet's discomfort. Understanding the key differences between ear mites and ear infections can help you communicate more effectively with your veterinarian and understand why a proper diagnosis matters.

The discharge is one of the most reliable distinguishing features. Ear mite discharge is characteristically dark brown to black, dry, and crumbly with a coffee-ground appearance. Bacterial ear infection discharge tends to be yellowish, greenish, or brownish and is typically moist, creamy, or pasty in consistency, often with a strong, foul odour. Yeast ear infection discharge is usually brown, waxy, and has a distinctive sweet or musty smell that many describe as resembling bread dough. While these descriptions provide useful guidelines, there can be significant overlap, particularly when ear mites have caused a secondary bacterial or yeast infection — which is common in chronic infestations.

The age and species of the affected animal also provide important diagnostic clues. Ear mites are far more common in cats than in dogs, and within cats, they disproportionately affect kittens and young cats. If an adult dog presents with an itchy, inflamed ear and dark discharge, an ear infection caused by bacteria, yeast, or allergies is statistically far more likely than ear mites. Conversely, a kitten with dark, crumbly ear discharge and intense scratching has ear mites until proven otherwise. Dogs with ear infections often have underlying predisposing factors — floppy ears that trap moisture, allergies, hormonal conditions, or frequent swimming — that increase susceptibility, while ear mites are more of an equal-opportunity parasite among cats.

Another differentiating feature is contagion. If multiple pets in the household are simultaneously showing ear symptoms, ear mites should be strongly suspected because of their highly contagious nature. Ear infections caused by bacteria or yeast are not contagious between animals — they result from disruptions in the individual animal's ear environment. Additionally, ear mites frequently affect both ears equally, while bacterial or yeast infections may be unilateral (affecting only one ear) or markedly worse on one side. Ultimately, the only way to know for certain what is causing your pet's ear problem is to have your veterinarian perform an examination, which typically takes only a few minutes and provides a definitive answer that guides effective treatment.