Why does your dog keep getting ear infections?

Ear infections in dogs can be extremely frustrating to deal with. They are considerably painful and stressful, and they tend to have a high recurrence rate.

They also are unfortunately one of the most common reasons people take their dogs to see a vet. If your dog is constantly shaking their head and scratching their ear, if you’re noticing an unusual smell around them as well as maybe a change in their behavior, rest assured you’re not alone. It is quite normal for us, as veterinarians, to come across 2 or 3 ear infection cases a day, and this number tends to increase during the warm season. And although people may be inclined to think that, since it’s such a common disease, its treatment must by now be standardised and straight forward, the truth is a bit more complicated than that.

The term “otitis” is used to address a variety of conditions that may present the same symptoms but are caused by different factors and/or organisms.

Imagine for a moment bringing your pet to your veterinarian because he/she is vomiting: this can be caused by gastritis, foreign bodies, intoxication, kidney disease, liver disease, cancer…and the list goes on. We can easily stop the vomiting as such, temporarily, but if we don’t address the primary problem it’s only a matter of time before not only the symptoms resume, but the whole picture gets worse. 

Same thing goes for ear infections. Blindly prescribing antibiotic drops is far from being a definite solution.

But before we get straight into treatment, let’s take a moment to reflect on what actually causes this disease, so we can better understand why certain steps may be recommended and why they can be more important than we tend to think.

There are 4 factors that may be playing a role in the manifestation of an otitis, and the latter is often the result of at least 2 of them. Treating for one of these factors, without considering the others often leads to recurrence after recurrence. And the more it keeps happening, the harder it gets to treat, that is a pretty solid rule in medicine.

So here is what comes in play when your dog starts presenting symptoms of otitis.

• Predisposing factors: these won’t cause the infection on their own but will dramatically increase the risk of it happening. Such factors may include anatomical features of the ear, excessive humidity, obstructions (polyps, tumors, cysts…) and other structural changes to the ear canal.
• Primary factors: they’re the only ones that may cause an ear infection on their own, although this isn’t usually the case. Such factors include parasites (usually mites), allergies, foreign bodies such as grass seeds or sand, immune mediated diseases, metabolic diseases and alterations of the ceruminous glands (glands which produce ear wax).
• Secondary factors: typically bacteria or yeasts that can be found in a normal ear which can cause otitis if the tissue structure in the ear is altered by a predisposing or primary factor. They are fairly easy to highlight through some basic microscopy but they are NEVER the only cause of infection. 
• Perpetuating factors: these are progressive alterations of the ear, which are usually found when the infection becomes chronic. They will not only worsen the infection itself but also prevent it from resolving despite treatment. If not dealt with promptly, they can eventually lead to what we call “end stage otitis”, which is that point of no return where the only curative approach is the surgical one. The most common perpetuating factor we see in general practice is that wet, brown, smelly discharge you’ll typically find (and smell) in your dog’s bad ear. It is the main reason we often recommend a thorough cleaning before applying any form of treatment. Another more advanced one is what we call stenosis, which is swelling of the soft tissues inside the ear due to their chronic inflammation. A stenotic ear will “trap” all of that discharge, bacteria and yeasts in the deeper part of the canal, making it virtually impossible to clean and treat appropriately, unless that swelling is reduced, if possible.

So going back to our headline: why does your dog keep getting ear infections? By now you can probably see how a superficial clean and antibiotic drops are only going to address secondary and perhaps perpetuating factors (if done correctly), leaving your dog still exposed to predisposing and primary ones, hence the high chance of recurrence. 

Now don’t get me wrong, secondary and perpetuating factors ARE the first ones that should be approached, after all our aim is initially to give relief as quickly as possible and to stop the spreading of the infection. But most of the times to succeed in controlling the symptoms doesn’t necessarily mean succeeding in treating the disease. 

Some of the most common primary causes for otitis are skin allergies, which interestingly often manifest themselves only in specific parts of our dog’s body, such as front feet and ears! These are often under-diagnosed, especially when the symptoms of a secondary infection are way more obvious. 

On the other hand, two of the most common predisposing factors are excessive humidity and the anatomical conformation of the ear. 

You can see how once the cleaner and drops have done their job (if they have at all), the problem is far from resolved, all of these factors are still there. If your dog was allergic to grass, he still is allergic to grass. If his ear was excessively humid and he keeps swimming every day, it will keep being excessively humid.

So I guess we now have all the elements we need to wrap this up.

Why does your dog keep getting ear infections? Because there often is no follow up once the symptoms are controlled. It feels unnecessary to investigate underlying skin conditions. It feels cruel to stop our faithful companion from diving into the sea and enjoy life. Yet the only way we can break this infection – treatment – recurrence pattern is to address all aspects of this frustrating problem.

And I know it often feels like a rip off, especially if your “Charlie” is feeling much better now! But unfortunately medicine is all but simple and straight forward, and believe me when I say that all we, as vets, really want for your dog is for him to heal once and for all. And that every step we recommend is to serve that one purpose: to take care of your hairy loved ones :)