A client and I recently chatted about how so many dogs in her walking group get ear infections in the summer. While some of the dogs swim, most of them didn’t. So, she wondered why they were all getting “swimmer’s ear”.
For starter’s I feel that “ear infection” is one of the most inappropriately used terms by veterinarians, myself included. When people hear “ear infection”, they think about inner ear infections (inside the ear drum) like the ones little kids get. While we do see these infections in dogs, it’s pretty rare. A more appropriate term for us to use would be “skin infection of the ear canal”. The medical term is otitis externa and, in humans, water trapped after swimming is the most common cause. Unlike us though, dogs shake the bejeezus out of their heads after swimming. So, water is rarely trapped to the level to cause infections. The most common cause is actually allergies.
A dog’s ear canal is 4-6 times the length of a human’s; basically a long tunnel of skin with a 90 degree bend halfway in. Normally, that skin is healthy and acts as a barrier between germs and the meaty tissue just underneath it. On other parts of the body, trauma to the skin can allow these organisms to get into that deeper tissue and spread. This infection then makes the dogs chew and scratch even more until the area becomes a “hot spot”. The ears are no different. Unless they were recently cleaned, the surface of the ear canals always has a layer of bacteria and yeast sitting on it. All they need is a little damage to that skin and the ear canal becomes infected. As I’ve discussed in the past, allergies don’t just cause rubbing of the eyes and noes like they do in people. Allergens can also get into the skin of dogs and stimulate the brain to tell them to scratch and rub, leading to hot spots. In the case of the ears, the closed, warm environment makes this a perfect incubator, and the infected skin within is much worse off.
This doesn’t mean that dogs can’t still get infections from swimming. Enclosed waterways near housing tend to have higher bacterial counts. This can be worse after rainstorms when older septic systems and public sewer overflow releases effluent into the water and cause direct infections. Avoiding these types of beaches, especially after storms, is one way to reduce the risk of ear issues. Another is to reduce or eliminate the water from the ear. Since the ear canals are so long, simply wiping the ears is not enough. Veterinarians carry special ear flushes that are safe from cause inner ear damage. Instilling this into the ear will displace the dirty water and encourage drying.
While these outer ear infections are not as nasty as inner ear infections, we still take them very seriously. They can still spread into the deeper ear causing damage or deafness. Also, even treated infections can lead to scar tissue buildup over time when infections are recurrent. This buildup can be so bad that the ear canal may eventually require surgical removal. Preventing them with a good anti-allergy regimen and regular cleaning is crucial.