by John hluebner, DVM

Dear Dr. Dog: My Beagle puppy, Amanda, began pawing at her ear a few days after we went to the beach. The vet tells me she has an ear infection. Can you tell me more about this problem, and especially how Ican prevent it in the future?

Most dog owners have to deal with ear infections at some time or another. In fact, canine ear infection is one of the most common problems veterinarians see. If Mother Nature had consulted with a veterinarian before designing the dog ear, a much simpler, less problem-prone model would have been recommended!

The basic internal structure and function of the canine ear is similar in many ways to a human. The similarity ends, though, when we start looking at the external ear canal or tube; that portion of the ear outside of the eardrum. This is where most of the problems with dog ears originate.

Dogs have a long, elbow shaped external ear canal that leads from the external ear opening (that hole we can see) to the eardrum. The "skin" that lines this canal is continuous with the skin on the side of the face and head, and is likewise inhabited by microorganisms such as bacteria and fungi (yeast). On the skin surface of the healthy ear canal, these organisms are present in very small numbers and cause no problems. They're part of what's called the "normal flora" of the ear canal and represent a balance between microbe growth and natural defenses.

This delicate balance is kept in check by the dog's healthy immune system. When it becomes compromised, the normal flora of the ear canal can multiply unchecked. In large numbers, these usually harmless microbes can cause some pretty severe problems. Unfortunately, there are many things that can compromise the ear canal's defenses and ultimately result in a bacterial or yeast overgrowth. The two most common culprits are increased moisture in the ear canal and allergy. It's very common for ear problems to develop a few days after a dofhas had a bath or gone swimming.

I encourage' owners to put cotton balls in their dog's ears before baths to minimize water penetration into the ear canal. If your dog swims often, talk with your veterinarian about a preventative program to head off potential ear problems. Fortunately, not all dogs that swim develop ear .problems. As a general rule, check with your vet before putting anything into your dog's ears.

Water can cause ear problems in dogs, but the most common predisposing factor is an underlying allergy. If we recall that the ear canal is basically an extension of the skin, it's easy to understand why so many dogs with other allergies also have ear problems. Perhaps the most common infection! overgrowth seen in the canine ear canal is a particular type of yeast, Malczssezict pachydermatitis. A dog with this problem will usually develop pain that causes him to shake his head, paw at his ear, hold the ear down, and even cry out if you touch the ear. Stoic dogs.Tiowever, might show no sign of discomfort. A dark yellow- to brown-colored waxy discharge from the ear is often seen and there also may be a bad smell.

An accurate diagnosis can only be made by close evaluation of the ear canal. A microscopic evaluation of some of the debris from the sore ear can help differentiate yeast overgrowth from such other problems as bacterial overgrowth or earmite infections. Foxtails and, rarely, turnors can also cause sore ears in dogs.

Whatever the underlying cause, the initial treatment usually involves gentle flushing of the ear canal to break down and remove waxy debris. Once the ear canal has been carefully flushed, otitis externa in dogs is best treated with topical medicine put directly into the ear canal for several days.

It is crucial to follow your veterinarian's instructions for treating the ears once you get home. I frequently see ear problems that at first appear to be resistant to treatment, then I later find out that the owner wasn't sure how to properly medicate the ears. Follow-up visits are important, so your veterinarian can check your dog's progress and possibly make changes in the treatment plan.

Canine ear problems can be challenging for susceptible dogs, dog owners, and veterinarians alike, but it's encouraging to know that they can be readily controlled with an accurate - diagnosis and appropriate treatment. .

Dr. John Huebner is a graduate of the School of Veterinary Medicine at UCDavis and practices companion animal medicine at Redwood Veterinary Hospital in Vallejo.

September Bay Woof SF.

Courtesy of Samoyed Club of Victoria