Ear mites (Otodectes cynotis) are a common and highly contagious cause of intense ear itching in cats, producing a characteristic dark, coffee-ground discharge in the ear canals. Most cases resolve quickly with a single topical treatment, but delaying care leads to secondary infections and self-trauma from scratching.
Last reviewed: June 2026
What Are Cat Ear Mites?
Ear mites are tiny arachnid parasites (Otodectes cynotis) that live in the ear canal, feed on skin debris and wax, and reproduce rapidly. They are the most common cause of otitis externa (outer ear infection) in cats and kittens and are readily transmitted by direct contact between cats and between cats and dogs. They cannot complete their lifecycle on humans, but can cause a brief, self-limiting skin irritation if transferred. As described in Nelson & Couto's Small Animal Internal Medicine, Otodectes is responsible for approximately 50% of feline otitis cases — far higher than the proportion seen in dogs.
The AAFP-AAHA Feline Life Stage Guidelines, 2021 recommend regular ear inspection as part of routine preventive wellness care, since early mite detection allows rapid treatment before secondary yeast or bacterial overgrowth complicates the infection.
Signs of Ear Mites in Cats
The hallmark combination is intense ear-scratching plus dark discharge:
- Vigorous head-shaking and ear-scratching, often causing skin wounds behind the ears
- Dark brown or black, crumbly ear discharge resembling coffee grounds or dried blood
- Odor from the ear canals (mild in uncomplicated cases)
- Redness and swelling of the ear canal opening
- Scratch wounds or hair loss on the skin behind the ears and on the neck from self-trauma
- Head tilting in more severe cases where the middle ear is involved
Many cats harbor ear mites without dramatic visible signs; an ear examination at wellness visits often reveals subclinical infestation.
Diagnosis and Treatment
Diagnosis is confirmed on otoscopic examination — the mites are visible as tiny white moving dots against the dark discharge — or by microscopic identification of debris from the ear canal. A veterinarian may also perform an ear cytology to rule out concurrent bacterial or yeast infection, which is common when mites have been present for weeks.
Treatment is highly effective. Selamectin (Revolution) or moxidectin-based topical spot-on treatments applied once to the skin of the neck kill mites systemically and remain effective for 30 days — preventing reinfestation. Older ear-drop treatments (pyrethrins, ivermectin, milbemycin) applied directly to the ear canal also work but require 3–4 weeks of daily application. All cats and dogs in the household must be treated simultaneously, or reinfestation will occur within days. A thorough ear flush by the vet removes the debris that harbors eggs and mites, speeding resolution.
When to See a Vet
Call your vet today if:
- Your cat is scratching its ears intensely or shaking its head repeatedly
- You see dark, coffee-ground discharge in one or both ear canals
- Your cat has skin wounds on the back of its head or neck from scratching
- A new kitten has been introduced to your household and is showing ear signs
Go to the ER immediately if:
- Your cat has a sudden head tilt combined with loss of balance
- The ear appears extremely swollen or painful to the touch
- Your cat cries in pain when the ear is touched
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Frequently Asked Questions
How did my indoor cat get ear mites?
Ear mites are transmitted by direct contact with an infected cat or dog. Even a brief contact — a grooming visit, a stay at a boarding facility, or contact with an outdoor animal through a screen — is sufficient. Cats that have never been outdoors can still acquire mites from a newly adopted cat or dog brought into the home.
How much does treating cat ear mites cost?
A vet exam and ear cytology typically runs $80–150. A single-dose selamectin (Revolution) treatment for one cat costs $25–50; treating all pets in the household adds to the total. Ear flush performed at the vet costs $40–80. Total for a straightforward case: $150–300 for all pets in the home. Untreated secondary bacterial infection adds antibiotic costs.
Can I use over-the-counter ear mite drops for my cat?
Over-the-counter pyrethin-based ear drops are available and can kill mites, but they require daily application for 3–4 weeks, have lower efficacy, and do not address any secondary infection. Prescription products (selamectin, moxidectin) work in a single dose and are considerably easier to use correctly. A vet visit also identifies whether secondary infection is present and requires separate treatment.
Will ear mites go away on their own?
Ear mites do not resolve without treatment. They reproduce rapidly — a full lifecycle from egg to adult mite takes about 3 weeks — and infestations worsen over time. Untreated mites lead to self-trauma, chronic otitis, and rarely middle ear infection. Prompt treatment is the fastest, most humane resolution.
Are ear mites contagious to my other pets?
Yes — Otodectes spreads readily between cats and from cats to dogs by direct contact. All cats and dogs in the household must be treated at the same time, even if they appear symptom-free. Rabbits and ferrets can also harbor ear mites, though a different species is more typical in those species.
Still Not Sure if Your Cat Needs a Vet?
When you're not sure if this is wait-and-see or call-tonight, Voyage AI Vet triages in under 2 minutes. Describe what you're seeing in chat, share a photo of the inside of your cat's ear and any discharge visible at the entrance, or hop on a live video call if you want a second pair of eyes. Every answer comes with citations to the actual veterinary literature it's pulling from — so you see exactly where the guidance comes from, not just a chatbot's word.