Control, not cure, may be goal for ear infections

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By John Koch, DVM

Question: My dog has had a long-standing problem with his ears. I treat them, and they get better. They seem better for a while, and then they get worse again. It has gone back and forth like this for several years. Someone suggested that my dog might have ear canker. I have never heard of ear canker. What is it?

Answer: Ear canker is an old-time term often associated with a dark blackish wax buildup and infection in the ear canal (otitis). Glands that line the skin of the ear canal normally produce wax. The deep L-shaped structure of the ear canal make elimination of this substance difficult for many dogs. Dogs like cocker spaniels and bassetts have long, heavy earflaps that prevent air circulation and drainage. Poodles often have small ear canal openings and heavy hair buildup within the ear, and that makes the more likely to have problems. Some breeds, especially German shepherds and dachshunds, are simply prone to excessive wax production.

Excessive wax buildup causes inflammation, and inflammation makes the ear more susceptible to infection. Initially the infection is reasonably well treated. But the underlying problems described above still exist, so ear problems keep returning. Over time, the lining of the ear canal becomes fibrotic (i.e. thickened and scarred). The numerous microscopic cracks and crevices in fibrotic tissue harbor disease-causing organisms that medication has difficulty reaching. At this stage, even with treatment, ear infection is almost constant.

Another important point regarding chronically infected ears is allergy. Approximately 70 percent of dogs with chronic ear infection also suffer from inhalant allergies. Inhalant allergies frequently cause inflammation of the ear canal lining. As previously mentioned, inflammation is the precursor of infection.

While books have been written about ear infections in dogs, otitis is a complex disease for which control and not cure is often the only achievable goal.

Dr. Koch is a Cape Girardeau area veterinarian.