September 02, 2016
Question: My five-year-old female black Lab has major ear problems for a large part of the year (May through September/October). Dark colored junk builds up in her ears and I can't get them cleaned up very well.
First she starts shaking her head, then you can see the dark stuff down in the ears. We have tried several different medications each year but we keep having problems. I would like to stay ahead of it this year. What should we do differently? — DB
Answer: Ear problems seem to be worse in the warmer months. The reasons for this are increased plant growth and increased dog activity. Growing plants can contribute to seasonal allergies that can sensitize the skin within the ear canal. The itching and self-trauma that follows can allow the normal yeast and bacteria of the ear to take advantage of the damaged skin defenses and infect the ear, causing more itching and trauma. I also think mature plants with pollen and seed heads can cause foreign body reactions and upset the health of the ear canal.
Increased activity of the dogs in the spring, summer, and fall months obviously increases exposure to plants and swimming. Swimming can be directly related to ear problems in some dogs.
So prevention of the inciting cause is the first part of the solution. We are still going to run and swim our dogs. But if we can identify and desensitize the dog to an allergen, we may help prevent the problem. Identifying the allergens is done by skin testing or blood testing by a couple different animal health companies.
Once the allergen is identified, the company can make an injection series to desensitize the dog. Also some of the allergens may be avoided altogether as a management plan. Avoiding swimming is not an option for our waterfowl retrievers, but we can use drying agents following swimming sessions.
Diagnostics for an ear problem also involve an exam with an otoscope to try to visualize the horizontal ear canal and the eardrum. Dog ear infections are typically on the outside of the eardrum. Seeing down to the eardrum can be a challenge if debris is still present in the horizontal canal. Complete cleaning and drying is often needed. If the ears are too painful, the cleaning and exam may need to be done under sedation or anesthesia.
Cytology of the contents of the ear canal should be evaluated. This is done by using a cotton swab to obtain exudate from the canal and rolling it out on a microscope slide then staining and examining it for yeast, bacteria, and mites. Ear mites are a common problem in outdoor cats, but are uncommon in dogs.
Most of our treatment medications are effective against both yeast and bacteria. Two major types of bacteria are found, rods and cocci. Caution and extra effort are needed when the rod shaped bacteria are present. These bacteria such as Pseudomonas and E. coli are the hardest to treat. When they are present the ear often has a slimy exudate as opposed to the more common dark dry debris.
Effective ear cleaning and treatment usually comes down to frequency or lack of frequency in failures. When debris is present we have to remove it with cleanser solutions so the actual therapeutic drugs can make contact with the skin in the ear. Daily cleaning is often needed initially. Actual treatment of the ears with medicated ointments typically needs to follow cleaning by hours not minutes. If done at the same time some of the medications may be neutralized.
Historically the treatment medications were applied daily for 7-10 days. Now there are medications that can be placed that are supposed to form a gel layer that binds to the skin and keeps antibiotics in place for 1-2 months without additional cleaning and treatments. Prior to placement of these long lasting medications the ear needs to be thoroughly cleaned.
Ultimately you must be able to clean the ear very well before effective treatment can occur. If this must be started under anesthesia, then the sooner the better. This may be the only reasonable option to avoid pain for the dog. Good luck!