Why do dogs get ear infections?
Year after year, national statistics point out that the most common diagnosis made in a veterinary practice is Otitis Externa. This is the medical term for the common ear infection that many pet owners have been frustrated with at some point in their pet’s lives. We are going to discuss here why this is so common and what we can do to prevent it.
We must first understand the difference between dog ears and human ears. When human ears are infected, it is commonly a middle/inner ear infection. This occurs when bacteria and fluid accumulate inside the ear drum. Typically, this is related to sinus congestion and swelling from a cold, allergies, etc. Dogs acquire inner/middle ear infections as well, but the vast majority of infections are external, meaning outside of the ear drum.
The dog’s external canal is a long dark tube. This tube is lined with some hair follicles, skin, and ear wax that all function to keep them clean, dry and protected. Pet’s naturally have some normal bacteria and yeast in the canal similar to what we find on all other skin. The Otitis Externa condition occurs when the ear becomes inflamed and creates a humid environment allowing those natural yeast and bacteria to overpopulate the canal. Then more heat, swelling, and humidity occur and so the cycle continues. At Firehouse, we often use the example of a leaky faucet under the kitchen sink. In that analogy, we know that darkness, moisture, and warmth is a perfect environment for mold (a fungus) to grow. The same principles apply to dog ears. When there is moisture, darkness, and heat, the fungus inside the ear, yeast, begins to grow.
This process can be very obvious or may go unrecognized. The typical symptoms that an owner may notice includes odors, swelling, or discharge at the external ear. The dogs may be very itchy and shaking their head. Some pets will show signs of discomfort like whining or change of behaviors. At Firehouse, we examine the entire ear canal visually and make a swab of the canal to microscopically evaluate what organisms we may need to treat.
Several factors contribute to the development of ear infections. Long ear canals and floppy ears are all predisposing factors. This is why certain breeds like spaniels and hounds are over-represented with ear infections. Dynamics that create moisture, like swimming and bathing, can also contribute to creating humidity. The last important ingredient of Otitis is inflammation. This may exist related to parasites, injury, or underlying allergy. It is very common for patients with environmental or food allergies to flare and initiate an ear infection.
TREATMENT & PREVENTION
Once identified, veterinarians have two important tasks relating to otitis cases. The first is to treat the active infection. This is typically done by using a combination of topical and systemic medications. These medications kill the yeast or bacteria that are present and decrease the inflammation. The second important task is to prevent recurrence by managing any underlying reasons causing moisture or inflammation. This may include drying agents, ear cleaning, and treatment of allergic disease. Depending on the pet and their contributing factors, we want to tailor a prevention program for each pet individually.
If you are frustrated by ear infections or would like to know more, please call us at Firehouse Animal Health Center 512.765.9009.