Earache is miserable. Recurrent earache is worse.

Why do some dogs seem to have perpetual ear problems, and others never?

The answer, as usual, is rarely straightforward. The ear canal is a long tube of cartilage, lined with modified skin. At the end is the ear drum (tympanic membrane), and beyond that, the middle ear bone (tympanic bulla, shaped like a cauldron).

Canal design can vary with breed – poodles' can be super-hairy, bulldogs have canals that are narrow and scrunched-up compared to the size of the dog, and cocker spaniels have a defect in the lining of the canal that makes for recurrent infections.

The canal has resident bacteria and yeasts, like the skin between our toes. If the environment in the ear is upset, these normal bugs overgrow and infection results. Triggers include foreign bodies (grass seeds), ear mites, constant wetting from swimming, and over-heating. Over-heating can come from a hairy ear canal, a heavy floppy ear flap (e.g. springer or basset – no ventilation), or from the canal swelling up due to itchiness. A hot, itchy canal will behave like the toes of an Athlete’s Foot sufferer, and management will be similar. Achieving long term resolution requires addressing inciting causes as well as current infections – the dog equivalent of wearing cotton socks and better ventilated shoes. For some, this may be as simple as thinning the ear-flap fur or plucking the hair at the top of the canal.

Many recurrent ear infections are driven by skin allergies. Food/ pollen/ mould/ flea allergy can trigger the ears to itch, resulting in hot, sore, infections. For these dogs, allergy management will reduce the frequency of infections.

Sometimes, the dog is not allergic, but has another condition such as hypothyroidism or Cushing’s disease, that allows infections to take root. Managing the underlying disease will improve ear health.

Every infection results in a more scarred and narrowed ear canal. Eventually, really nasty bacteria move in, including E coli and Pseudomonas. These bacteria cause ulcers in the canal wall (ouch!), eat through the ear drum and invade the middle ear. Once there, they are very hard to shift; ear drops cannot penetrate the middle ear bone, and give temporary relief at best. Microscopic analysis and bacterial culture are critical for these dogs. For some, the infection is so antibiotic-resistant and so deep-seated that complex surgery to remove the ear canal is the only cure. It sounds awful, but can revolutionise quality of life.

Where the issue is super-hairy canals or poor lining design, a smaller operation to open the canal can be curative if performed promptly, before scarring has developed.

To further complicate matters, most ear drops contain anti-itch, antibiotic, and anti-yeast ingredients. A dog who only suffers from yeast doesn’t need antibiotics! Additionally, some contain antibiotics that should be reserved for special use, e.g. marbofloxacin. While convenient, repeated use of these drops without due care leads to antibiotic resistance developing, making future infections more awkward to shift.

If you are used to just popping to the vet to get another bottle of antibiotic ear drops, please have a rethink. Similarly, if your dog’s red, gungy, painful ears are only receiving a cleaner, they ought to be getting more help than this.

Sometimes, the problem comes from the dog not receiving its meds properly – applying drops correctly, twice daily, for possibly 2 weeks, may not be made easy by the dog – once it looks a bit better, it is all too easy to stop the treatment. Similarly, if the canal is chock-full of wax, hair, pus etc., the medications will struggle to work. For dogs who are distressed by having their ears touched, possibly from so many infections, tablets by mouth may be an option. Also, there are now long-acting treatments, that can be applied at the surgery, under sedation if necessary, after cleaning out the canal.

If your dog springs to mind while reading this, please talk to your vet.

For further advice or information, please contact 124 Vet by calling 282 338 407, or visiting www.algarvevet.com, google/fb 124vet