Q I have a poodle mix that is 6 and never had any issues until July. One ear has a black almost tarlike substance with no smell. I have taken her to a local vet, who prescribed an antibiotic ointment in the ear; it helps but never completely cures the issue. Any suggestions?

A: Otitis external (inflammation of the outer ear) is an extremely common and often chronic problem in dogs. One study found that close to 15 percent of dogs presenting for evaluation at veterinary hospitals were there because of their ears. The large number and variety of products marketed to veterinarians for the treatment of ear disease in dogs also indicates how prevalent this problem is.

The ear canal is lined with tissue similar to skin that has glands that produce wax. Chronic inflammation alters the normal environment by causing these glands to produce excessive wax and the lining to thicken. This thickening narrows the canal, decreasing air flow and normal drainage. If severe enough and long term, calcium will deposit in the tissue, resulting in permanent changes.

Breeds with pendulous ears (spaniels and retrievers), those with excessive hair in the ear canal (terriers and poodles) and narrow canals (shar peis) are predisposed.

In many dogs, there is an underlying cause for the chronic inflammation, and the best treatment is to treat the cause rather than just manage the symptoms. Ear diseases often are brought on by the same problems that cause skin disease. If the underlying skin condition can be treated, often the ears will improve.

Dogs that have allergic skin disease, whether from environmental allergies (called atopy) or from food allergies, often have otitis too.

There are hormonal conditions that may alter skin and the lining of the ears, changing the environment and allowing bacteria or yeast to grow.

Hypothyroidism, resulting in low thyroid hormone, and hyperadrenocorticism, from an overactive adrenal gland, are the two most common.

Dogs have several parasites that can infect their ears, resulting in increased discharge and discomfort.

Dogs with pendulous ears that swim frequently may have issues from excessive moisture trapped in their ears. The bacteria and yeast associated with otitis externa like this warm, moist environment. We can see this occur with overzealous cleanings, too.

Foreign bodies, such as a piece of a plant, and tumors also can result in inflammation. These should especially be considered if only one ear is involved.

As with every disease, the best treatment is to address the primary problem and not just the symptoms. The single most important diagnositic tool is for a sample of ear canal debris to be evaluated under the microscope. This is inexpensive and usually can be done in the veterinarianís office, so results are back quickly. This will look for parasites, bacteria and yeast so a treatment plan can be formulated. Once treatment is started, repeat sampling is a quick way to evaluate how well it is working.

Regardless of the cause, one of the first treatments will be to clean out the wax and debris before starting any other therapy. This is important for multiple reasons. Foremost, it will allow the ear canal to be cleared out so that foreign bodies or tumors can be seen if present. Second, the debris prevents medications from reaching the areas where they are most effective, so removal of debris will improve treatment response.

If there is minimal debris and inflammation, cleaning can be done while your pet is awake. With significant disease, sedation often is necessary, as the required cleaning in a severely diseased ear can be painful. It also is important not to clean the ear too frequently, as this can damage the ear and cause inflammation, too.

Once the ear canal is cleaned, an otic examination is performed and the debris looked at microscopically, treatment can be started. Usually this will be an application of agents topically in the ear to kill bacteria, yeast or parasites. Occasionally, a steroid may be used to decrease the inflammation. In some severe cases, oral medications are given. This is typically done when the ear is so swollen and inflamed that medications cannot be administered.

If suspected, tests should be performed to look for an underlying cause that could be corrected to prevent recurrence. This could include skin testing to check for allergies and/or hormonal testing.

Severe cases of otitis externa can spread through the ear drum and into the middle ear. This is usually painful and may cause vertigo. Dogs generally will tilt their heads to the side and often be unsteady when walking. You also may notice spontaneous rapid horizontal eye movement.

In severe cases that have chronic disease resulting in calcification of the ear canal and middle ear disease, medications no longer help. These dogs have to have the ear canal removed. While this procedure sounds drastic as it does decrease hearing, it is amazing how much their quality of life improves.

So our suggestion to you is to have your vet clean out the debris in your dogís ear and perhaps teach you how to do this as well. Based on the evaluation, start the appropriate medications to treat the infection and decrease inflammation.

Finally, have them assess if there is an underlying cause that can be directly treated to prevent recurrence.

Dr. Henri Bianucci and Dr. Perry Jameson are with Veterinary Specialty Care LLC. Send questions to petdocs@postandcourier.com.