From Janet Tobiassen Crosby, DVM,
Your Guide to Veterinary Medicine.
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Please see the archive for more Q & A topics.

Itchy ears, scratching, shaking, and sometimes swollen ears are a common problem for dogs and sometimes cats, too. Click here for diagrams of the canine ear anatomy, courtesy of DVM Pharmaceuticals.

My dog is continually scratching her left ear and shaking her head. I used some Hydrogen Peroxide to wash it out, will that take care of it?
Probably not. Dogs (and cats) have relatively large ear canals -- a vertical canal from the outside of the ear down to the horizontal canal, which connects the vertical canal to the ear drum (Tympanic Membrane). See diagram to visualize the ear anatomy. It is important to have your veterinarian examine the ear and make sure that there isn't a foreign body (grass awn, twig), ruptured ear drum, etc. prior to cleansing. Your veterinarian can advise you on what would be the most appropriate cleanser for your pet and your pet's condition, and can show you how to properly flush the ear out to reach all of the surfaces of the ear.

My cat is scratching his ears. Can I get some mite medicine at the grocery store?
No, at least not in the United States. The first question to ask is... WHY is your cat scratching his ears? It may be ear mites (Otodectes), it may not be ear mites.

Whenever a pet (cat or dog) is scratching their ears, it is time for a trip to the vet. Your vet will examine the ear with an otoscope -- an instrument to visualize the entire ear canal and ear drum. Other conditions to rule out: fungal (yeast) infection, bacterial infection (primary or secondary to some other condition), tumors or polyps, foreign bodies (grass awn, foxtail), excessive hair in the ear canal (leading to build up of wax and debris) to name a few.

Ear mites are probably the most "well known" of feline ear problem possibilities, but rare in adult animals that have not had contact with a puppy or kitten that has them (most common form of transmission). Ear mites are obligate parasites, meaning that they have to live on the host animal, so physical contact with an infected animal is necessary for spread. The mite life cycle is 3 weeks from egg to adult, therefore the treatment must span 3 weeks to rid the pet of the infection. Your veterinarian can recommend an appropriate prescription medication (miticide) and dosing schedule if your pet is found to have ear mites. Click here to read more about ear mites and the treatment for a pet with ear mites.

I came home from work today, and my dog's ear is huge! He was in his kennel all day, nothing appears out of line, but he was scratching at his ear yesterday and this morning. What happened?
If the ear flap itself is swollen and turgid, it is likely that he has something called an aural hematoma. 'Aural' refers to ear, and 'hematoma' is a blood-filled space. This happens when small blood vessels in the ear flap rupture and blood fills the area between the skin and ear cartilage. Click here to see a photo of an aural hematoma. If the ear/face is diffusely swollen, your dog may have experienced an insect bite or sting. Either way, a trip to the vet is in order!

Aural hematomas frequently occur in conjunction with an ear infection of some sort (fungal, bacterial, mites, etc.) and results from the trauma of continually shaking the head and scratching. Some pets may actually hit the ear flap on a table or surrounding object, but most often, it is the continued shaking/scratching of the ears to cause the blood vessels in the ear to rupture. Aural hematomas happen in both cats and dogs, but more commonly in dogs with floppy ears.

Hematomas are uncomfortable, and the extra weight may cause the pet to shake the head even more. Left untreated, the hematoma will resolve in a few weeks time, usually resulting in a permanently wrinkled "cauliflower" ear. Treatment options include: 1) aspirate (using a needle), 2) surgically open up the ear flap, drain the space and remove clots, then tack the ear down, or 3) place an indwelling cannula in the ear to drain away fluid as the ear heals. Aspiration has risks -- the possibility of introducing infection, and the possibility of reoccurring. Surgery is the quickest way to resolve the hematoma, and will hopefully reduce the wrinkling, but once an ear has had a hematoma, there is often some wrinkled scar tissue present. Not many dogs tolerate the cannula option, so this is not as common of a treatment. The severity of post-hematoma wrinkling of the ear depends on how large the hematoma originally was.

Text: Copyright © Janet Tobiassen Crosby. All rights reserved