Chronic Ear Infections
Dogs can have some of the nastiest ear infections (otitis) you can imagine. And,
unfortunately, some dogs have severe infections most of their life. Although we may not
be able to eliminate all ear infections in dogs, we certainly can manage chronic ear
problems so that dogs don’t have to suffer the pain and itching associated with these
It is easy to look in a dog’s ear and diagnose an ear infection, but if this problem is
recurring, one has to look beyond the diagnosis of “otitis” and search for the underlying
cause. Searching for the cause can be a hit-or-miss affair and it requires patience on the
part of the veterinarian and the pet’s guardian.
Ear mites are commonly accused of causing ear problems in dogs, but actually, ear mites
in dogs are quite rare. Puppies housed in kennels might have ear mites and occasionally
one finds mites in hunting dogs who are housed with hundreds of other dogs, but in
general, an adult pet dog will not have ear mites. Fortunately, if mites are present,
treatment is fairly simple. Cleansing coupled with treatment with topical insecticides is
very successful. After treating the mites, a medication to control the itchy inflammation
and secondary infections can be very beneficial.
If adult dogs don’t get ear mites, then what causes their infections?
A one-time infection is usually caused by common bacteria (staphylococcus or
streptococcus) or by yeast. These are easily cleared with appropriate cleansing and
antibiotic/antifungal/anti-inflammatory combination products for 10 days. But, when an
infection comes back, we must look further.
In this case we are looking for two things. The first is the causative organism. For
example; is there a bacteria or yeast that is now resistant to our usual antibiotics? We
begin this search by looking at samples under the microscope and by sending samples to
the lab for a culture. The second thing we are looking for is a cause that encourages these
bacteria or yeast to set up shop.
The ear has normal defense mechanisms that clear normal debris and organisms. An
infection will establish itself only if one of these defense mechanisms is impaired. For
instance, if there is a polyp or tumor in an ear canal, the normal waxy surface may be
replaced with abnormal tissue that traps organisms. Obviously, finding and removing
any such invasive material would solve the problem. Often sedation and exploration of
the ear canal is required to find the polyps or tumors.
Some dogs have excessive hair growth in their ears. Most breeds that require grooming
also require periodic hair removal from their ears. Excessive hair makes it difficult for
the ear to dry out. Bacteria and particularly yeast love the warm moist environment
protected by the hair. Controlling the hair accumulation and appropriate cleansing can
help these dogs a lot.
The most common cause of recurring ear infections in dogs is allergies. When a dog is
exposed to something that it is allergic to, the skin gets inflamed. The lining of the ear is
merely an extension of a dog’s skin, so this area gets inflamed too. An inflamed ear is
warm and moist and, as mentioned before, yeast and bacteria love this. As infections
recur, the ear thickens with scar tissue and it gets harder and harder to keep the ear canal
dry and cool. This sets up the cycle of infection after infection. These dogs desperately
need sedation, a thorough ear flush and culture of the inner ear. Then may even need X-
rays to see how deep the infection goes. Then they need to begin testing and treatment
Testing for allergies is no easy task. Before testing for environmental allergies like
pollens, it is recommended that the pet begin a food trial, because, believe it or not, an
allergy to a food or something in the food is the most common cause of chronic ear
problems. There is no simple test for a food allergy. Only supervised, specific dietary
changes can help determine if your dog has an adverse reaction to something he is eating.
It takes at least 8 weeks after a food change to see if your dog is improving on the new
routine, so great patience and commitment is required. Some veterinarians recommend
prescription diets for this purpose and others recommend feeding specific and very
restricted home-made diets. You cannot give any treats during this time and you cannot
even give your dog oral heartworm prevention during this trial because the flavors in the
tablets could be the cause of the allergy!
However, all of the above work will be worth it if in 8 weeks time your dog is beginning
to get some relief. Usually anti-inflammatory tablets as well as antibiotics or antifungals
as indicated by the cultures will have been started before the food trial is completed, so as
the medications begin to run out, the ear infection should not recur if the food trial was
For those dogs who have allergies to pollens, house-dust-mites, or other environmental
causes, the food trial won’t work. For those, more extensive blood or skin testing is
required and long term medication with drugs like prednisone or cyclosporine may be
necessary to keep your dog’s ears healthy and happy.
Ear cleaning is an important component to any ear treatment. To do this, get advice and a
demonstration from your veterinarian. All veterinarians have solutions and preparations
that they prefer, but you can do a lot of harm by using water, hydrogen peroxide or other
household products without first learning how to make appropriate mixtures.
Managing a chronic ear problem will require a lot of time and effort on the part of the
pet’s caretaker, but it is essential that one commits to a routine that will keep the dog
happy and healthy.