Hearing Problems in Cats and Dogs

I’ll bet that of all the "routine" health problems seen by veterinarians on a daily basis, ear problems rank as the most frequent. Not a day goes by in any animal hospital without a cat or dog being presented because of itchy, inflamed, smelly, bloody or crusty ears. Why this is so is actually an easy answer. What to do about the problems can be a real challenge.

Why do cats and dogs ears so commonly encounter difficulties?

The answer lies in the anatomy. If scientists wanted to design a perfect incubator for growing and sustaining microorganisms and parasites, they’d end up with a dog or cat ear. I’m not talking about the ear flap, that floppy flag on the bounding Cocker Spaniel and the erect sound reflectors standing atop you cat’s head.

The earflap is called the pinna and rarely presents problems for the pet. An occasional dog is seen with what is termed a Hematoma of the pinna; a blood vessel breaks over the cartilage of the earflap and a large blood deposit forms. This can be treated with minor surgery.

But that incubator…the tissues at the base of the pinna and continuing down into the ear canal and eventually ending at the ear drum…THAT'S a perfectly designed incubator, a perfect environment for microscopic life! If that area gets enough air ventilation, does not have folds of tissue whose surfaces contact one another, and isn’t assaulted by dirt or irritating liquids, a small and balanced population of bacteria exist naturally.

But nature’s designs, although perfect for some organisms, may be destructive for another. Let’s take for example the Cocker Spaniel. Through years of breeding the Cocker has evolved an ear canal that is rather long and often even folds upon itself before reaching the ear drum. Often there are ridges of ear canal tissue that course down the upper ear canal, which increases the overall surface area... perfect acreage for growing all sorts of life. These ridges restrict the drying effects of airflow.

So you can see that if we start out with a structure that has too much mass for a small tubular canal, that structure will be less than ideal for a healthy existence. Add to all this fact that the ear canal isn’t a canal at all. It dead-ends at the eardrum! Anything that gains entrance to this ear "canal" will be pulled downward by gravity to its termination at the eardrum.

If water gets into the ear canal, which doesn’t necessarily create any problems, that water has to evaporate to disappear. Because of restricted airflow and the high humidity environment of the deep ear canal, that water remains present much longer than it would in a dog with an open and airy ear canal.

Bacteria have to have a water environment in order to multiply (that’s why Freeze-Drying is such a good method of "preserving" things); and a wet, warm, dark and nutritious soup awaits them deep in the Cocker’s ear canal. Think of the ear canal as a funnel with a wide opening at the top and a more and more narrow diameter as you progress downward. Now… plug up the end of the funnel with a delicate eardrum. How’s that for a collector of horrors?

As mentioned, there are normal types and numbers of bacteria in any ear canal. When the wrong kinds of bacteria (Staphylococcus and Pseudomonas are notorious criminals) meet with the wrong conditions (moisture, oils, dirt and secretions) these bacteria can overwhelm the environment. Now the ear canal’s thin surface layers react to the organism’s numbers and toxic waste products by secreting more oils and fluids in an attempt to sooth itself. Inflammation results in an increased blood supply (more heat) and chemicals are released onto and into the tissues. Histamine is a notorious irritant and is released into the tissues, which causes itching, and swelling and more tissue damage…a vicious cycle ensues. Now we have a dead-end canal that has restricted air circulation where even more swelling and inflammation is occurring taking the situation even farther from ideal. What’s to be done?

Treatment of Ear Problems

Medical:

Generally, at the first sign of a deep infection in the ear canal, topical ointments or sprays are utilized to kill off the bacteria. If the tissues are swollen and inflamed, oral antibiotics are used for ten days to inhibit the bacteria from gaining access to the ear canal tissues.

As you can imagine, that topical ointment can add to the soup that is already present in the canal so over infusing topical medications and ear washes can assist in flushing the pus and debris out of that blind end.

Many dogs will need to be sedated and given a thorough flushing and cleaning of the ear structures; to do so when fully awake may be impossible.

Long term treatment should always be a consideration because the conditions that allowed that first infection to occur are still present and maybe the conditions have been made worse because to that infection. Unsuccessful treatment is common.

Due in a major way to the anatomy, but also because of the multitude of resistant bacterial, fungal, yeast and parasitic organisms that enjoy living in the dog and cat ear canal, chronic Otitis Externa may respond best to surgery. After all, if the predisposing factor was an anatomy glitch, why not change that anatomy away from one that favors organism growth? Why not open up that funnel and let some drying fresh air in? Why not eliminate those folds and ridges and let that canal breath some fresh air?

Surgical:

That’s where surgery comes in. Many, many dogs have seen their quality of life improve vastly after surgery to open up the ear canal. There are different procedures depending upon the severity of the scar tissue and calcium deposits present and length of time the damage has been going on. Each surgery’s intent, though, is to remove as much scarred and infected tissue as possible, to eliminate folds and ridges, and to expose the deep area of the canal to fresh air. If surgery is done early enough, the procedure goes quickly and the amount of tissue to be removed is relatively small. Chronic, long term Otitis Externa may require major reconstructive surgery.

In either type of case, the payoff comes quickly. The dog heals rapidly and usually within two weeks the dog will actually let you know how much better it feels. The painful infections are gone; the hearing is improved (as long as the chronic infection didn’t damage the ear drum); the smell disappears; the medications lay unused; the dog can live in comfort without that continuous, agonizing ear affliction.