Canine Ear Infections
Diagram of canine ear canal and ear drum
Angel Oaks, Spanish moss, blooming plants, and warm humid air lend to the majestic beauty of the Low Country. But this beautiful climate also creates molds, yeast, fleas, and pollen that act as allergens for many people and dogs. With the beautiful spring weather, we start seeing more dogs with itchy skin and ears at the The Animal Hospital. The symptoms of an ear infection include: redness, discharge, odor, scratching the ears, and shaking the head. Ear problems can be very frustrating to diagnose and treat in dogs because they are often closely related to an underlying allergy.
Q: What causes ear infections?
A: Because the ears are lined with skin, ear problems are really a special type of skin disease. Allergic skin reactions PLUS humidity in the ear canal leads to secondary infections. The Journal of Veterinary Dermatology recently published a study regarding the predisposing factors for ear infections in dogs. Allergies of the skin were the most common primary cause of ear infections. Dogs with ears that hang, such as Basset hounds and Cocker Spaniels, are predisposed to ear problems. Other factors include endocrine diseases that affect the immune system like hypothyroidism. Dogs can suffer from ear mites, but parasites only accounted for 13% of all ear problems and usually only affect puppies.
Infected Dog Ear
Q: If my dog is itching because of allergies, why can't I just give him a Benadryl?
A: The allergy opens the door to secondary infections that require more specific short-term treatments. When the skin is red and inflamed from an allergy, the stressed immune system allows the bacteria and yeast that are normally present in small numbers to grow out of control creating a secondary infection. The Veterinary Dermatology journal lists yeast as the most common cause of secondary infections. At least one third of our patients have a mixed population of yeast and bacteria. This is why it is so important for your veterinarian to examine the ears at each visit and to perform an ear cytology with each new infection. Veterinarians routinely prescribe a medication that has both anti-yeast and anti-bacterial medications because of the prevalence of mixed infections. However, once we begin to see rod shaped bacteria creep into the cytology, or if there is a chronic ear infection, a broken ear drum, or a collapsing ear canal, more aggressive care is needed.
Q: What can I do to prevent ear infections?
A: ALOT! The most important thing you can do to prevent ear infections is to prevent allergies. For starters, dogs need to stay on a veterinarian approved, prescription flea prevention (Frontline, Comfortis, or Advantage) every single month. Flea allergies are the most common allergy in our area, and dogs can suffer from flea allergies even when you are not seeing any fleas!! Next, many dogs also have a food allergy. Do not allow your dog to eat people food. Feed a high quality diet such as California Natural Lamb and Rice, Purina One Sensitive Systems, Eukanuba FP Response, or a prescription hypoallergenic diet like Hill's z/d. Every dog has different diet sensitivities and it can take time and patience to find a diet that will work with your dog. Never change a diet abruptly. Gradually mix the old and new food together for several weeks to prevent stomach upset. Allow each new diet at least two months before giving up on the food. Remember that even small amounts of treats, people food, bones, and beef flavored medications like heartworm chewables can skew the diets' effectiveness. Finally, we must control atopic allergies to grass and pollen in the air. Since we can't keep our dogs in a bubble, some other options are: Prednisone, Atopica, and allergy testing for immunotherapy injections. One more thing! Any dog that has wet ear canals should have the ears cleaned with a drying and ceruminolytic (fancy vet word meaning "breaks up the wax") ear cleanser after a bath or a swim. Do not use Alcohol, Vinegar, Olive Oil, or any other home remedy, because they can cause more harm than good.
Hematoma in an infected dog ear
Q: My dog's ear flap is all puffy.
A: He or She probably has a hematoma. Some dogs that are suffering from an ear infection shake their head so much that they will burst the blood vessels in the flap, which leads to a large blood blister. We usually have to intervene surgically or the ears will become scarred and thickened over time, and it is uncomfortable to your dog too.
Q: My dog was shaking his ears, and now he is falling over!
A: Your dog might have a middle ear infection in addition to an outer ear infection. A veterinarian should examine him as soon as possible. These patients often need injectable medications, especially if they are nauseated and dizzy.
When it comes to ear infections, an ounce of prevention really is worth a pound of cure. Make sure to keep all dogs and cats in the household on flea prevention every month. Feed a good quality diet, and clean the ears regularly (2x/week and after baths/swims) with a vet-approved ear cleaner. If you still have to battle the occasional flare-up, make sure to give the full course of all prescribed mediations. Always keep recommended recheck examinations with your vet after prescriptions run out, as some infections need long-term treatments.
Reference
1. Aetiology of canine otitis externa: A retrospective study of 100 cases. Saridomichelakis MN, Farmakit R, Leontides LS, Koutinast AF. VET DERMATOL 18:341-347, 2007.
-Danielle Cain, DVM
The Animal Hospital, www.theanimalhospital.net, 843-552-8278.