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Tuesday, September 8, 2015

What Causes Ear Infections? And How Do You Treat Them?

Probably one of the top disorders that vets see on a daily basis is ear infections.  Most days I'll see at least one, and often several.  Some breeds and individuals are prone to them and we may see those patients for chronic, ongoing, or recurrent problems.  So why do some dogs get them so often?  What can a pet owner do to help?

I wish there was a simple answer, but unfortunately there isn't.  Ear infections, especially chronic ones, can be a challenge to diagnose and treat, and every case is going to be a little different.  Ongoing issues can take a lot of time and money to get under control and are usually frustrating for everyone involved.

One of the biggest reasons for ear infections is simple anatomy.  Dogs with floppy ears are more prone than dogs with upright ears because there is less air flow and moisture can't evaporate easily.  If water gets in the ear and stays there it causes irritation which can lead to an infection.  With upright ears there is good evaporation of the moisture.  But floppy ears close off the ear canal and don't allow good evaporation.  You then get a dark, warm, moist environment which can be a great breeding ground for microorganisms. 

Excessive hair in the ears is another problematic factor.  Many small, fluffy dogs have hair growing not just around the ear, but down inside the ear canal.  Common breeds include poodles, shih-tzus, bichons, Maltese, and similar dogs.  Think of the hair in the canal like hair in your sink drain.  Normal moisture and debris gets trapped and has a hard time getting out.  Just like having to clean your drain, it is often necessary to clean the canal.  This involves plucking the hair from the ears, which can be uncomfortable for the pet (about as bad as plucking your eyebrows).  Groomers will typically do this as part of their services or if asked, and vets can always do this.  Plucking the hair opens the ear canal and removes some of the blockages, allowing for more thorough cleaning and evaporation of moisture.

Dogs who frequently swim or get bathed are at a higher than normal risk for ear infections.  It goes back to the principle of excessive moisture remaining in the ears leading to an increased risk of irritation.  I will often see dogs come in with infected ears 1-2 weeks after being groomed or having go to the lake.  Dogs who have frequent water exposure or who have a tendency for infections should have their ears cleaned and dried after being in water. 

The other big cause of chronic ear problems is allergies.  In fact, recurrent ear infections can be the only symptom of an underlying allergy disorder.  The food or environmental allergy causes inflammation in the skin of the ear canals, making them irritated and susceptible to infection.  You can usually clear up the infection, but unless you address the underlying root cause you'll see the infection come back frequently.  So when your vet talks to you about doing trials of specialized foods or doing allergy testing, they really are trying to get to the bottom of the problem.  Some breeds have an increased likelihood of ear infections not just because of the ear anatomy but because these breeds are also prone to allergy disorders (such as cocker spaniels and Labrador retrievers).

The first step in treating an infection is to make the right diagnosis.  And that involves the vet looking at an ear swab under the microscope every single time.  I know it may seem like the vet is just trying to make money, but the composition of the bacteria and yeast can change from infection to infection.  Every dermatology specialist agrees that you do an ear swab and microscopic exam on every ear infection and follow-up, regardless of previous results.  Different kinds of bacteria can infect the ear and some of them may need to be treated differently.  There are also some kinds of bacteria that may have a higher likelihood of being resitant to treatment, so we need to look for those. 

If an infection just won't go away, it may be a resistant bacteria.  In these cases the vet will need to get a sterile sample and send it off for culture and sensitivity testing.  The lab will grow the organisms, identify them, and test them against various antibiotics.  I've had results come back where the bacteria is resistant to just about everything available, and these infections are particularly difficult to resolve.

Even if you treat the infection you still need to address the underlying cause if it is a recurrent situation.  For dogs with closed-off ear canals there is a surgery that can be done to open the ear canal and make it easier to treat (lateral ear canal resection).  Dogs with hair in the canals may need to have them plucked and cleaned regularly.   If there are numerous polyps or growths in the canals the pet may need surgery.  And of course the vet may talk to you about underlying allergy disorders, which can be difficult to diagnose and require life-long treatment.

If chronic ear infections are untreated they will lead to permanent damage to the ear canal.  Over time this worsens, leading to hardening of the cartilage of the ear and disruption in the normal function of the canal lining.  When an ear gets to this point it is impossible to completely resolve the infection, and the only long-term solution is to surgically remove the ear canal (total ear canal ablation, or TECA).

Chronic or recurrent ear infections are very frustrating to deal with as a pet owner and can cause significant discomfort to your pet.  Work closely with your vet in these cases, and really try to get down to the underlying cause rather than just continuing to put medications in the ears.