Signs of ear infections in a dog can include: head shaking, rubbing ears on the floor, discharge coming from the ears, a bad odor in the ears , and/or redness in the ears. Treatment for ear infections should be with a topical medicine designed to treat the yeast/bacteria or combination infection in the ears.
Occasionally, dogs with ear infections will shake their heads so vigorously that it can lead to bleeding within the ear flap. Bleeding within the ear flap It is called an aural hematoma. You can read more about this here.
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Types of ear infections in dogs
The most frequently encountered ear infection is a yeast infection. Yeast infections in dogs look like dark brown or tan waxy build up in the ear. First-time ear infections in dogs are most likely to be yeast infections.
The second most common infection seen in dog ear infections is a bacterial infection with Staphylococcus pseudintermedius. This bacteria lives on your dog’s skin in low concentrations. Less common causes of bacterial skin infections are caused by Pseudomonas aeruginosa, Proteus and Streptococcus canis.
Occasionally dogs will have ear mite infections. The most common ear mite in the dog is Otodectes. A more rare ear mite is sarcoptes. Sarcoptes (scabies) can cause itching in people too, but Otodectes cause no problem in people. If your dog takes Nexgard, Simparica, Advantage Multi or Revolution your dog’s ear infection should not be from mites. These drugs prevent and treat ear mite infections.
How does a dog get an ear infection?
Underlying allergies is the most common factor that leads to an ear infection in your dog.
Allergies in dogs
- food allergy
- environmental allergies
- contact hypersensitivity
To learn more about allergies in dogs, read this.
Other causes of ear infections are:
- Underlying endocrine diseases : hypothyroidism, Cushing’s disease
- Parasitic infections: ear mites
- Changes to the lining of the ear such as over growth of benign nodules lining the ear canal, tumor(s) in the ear
- Foreign material in the ear (grass awns are a common cause)
Some predisposing factors for dogs developing an ear infection
- Breeds with pendulous ears (ears that hang down) are more likely to develop an ear infection versus dogs with erect ears
- There are higher rates of ear infections diagnosed in the late summer and fall when there is higher humidity.
- Moisture in the ear following swimming/bathing
Factors that don’t predispose to ear infections in dogs
The amount of hair in the ear canal has NOT been associated with increased ear infections
How likely will it be that my dog’s ear infection will recur?
- Approximately 25% of dogs diagnosed with otitis externa will experience a recurrence
- Most recurrent cases of otitis externa are not diagnosed with a yeast infection.
Dogs that keep having ear infections may need to be screened for underlying predisposing factors such as endocrine disease (hypothyroidism, Cushing’s disease). Cultures of the exudate in their ears can determine if there is a drug resistant bacterial population.
Some dogs may benefit from longer courses of steroids to help reduce swelling of the ear canal followed by sedated deep ear flushing of the ear canal. Sometimes veterinary dermatologists will puncture the eardrum to collect a culture of fluid that may be present behind the eardrum to determine if the infection is more deep seated.
Very rarely, dogs with severe secondary changes to the ear canal will not be able to clear their ear infections. This can occur in dogs with tumors in their ear or bumpy overgrowth of tissue that lines their ear canal.
These changes can narrow the ear canal and trap moisture and bacteria or yeast in the ear. A salvage procedure can be performed to remove the ear canal completely. This called a TECA (total ear canal ablation) surgery.
How to diagnose an ear infection in your dog
When you bring your pet to the vet, they will perform an ear exam and collect a sample of the discharge from the ear and smudge this onto a glass slide. Using a microscope they can visualize any yeast or bacteria that are colonizing the ear canal .
On examination of your dog’s ears, an otoscope cone can be inserted into the ear. This cone is used to visualize the ear drum. The eardrum separates the external ear (the ear canal )from the middle and inner ear. Most ear infections only affect the external ear. If the eardrum appears unhealthy or diseased certain ear products may be avoided to prevent damage to the middle/inner ear.
What is the best treatment for an ear infection?
The best treatment for an ear infection is based on what the cause of the ear infection is.
If the ear infection is caused by yeast, a good product we utilize at my hospital is 1% miconazole lotion with 0.01% dexamethasone added to the bottle. The added steroid (dexamethasone) helps calm down the itch and inflammation which perpetuates the infection. Miconazole directly treats the fungal infection from the yeast present in your dog’s ear.
If there is a bacterial ear infection present, then the medicated ear drop will contain an antibiotic.
For mixed bacterial and yeast infections a medication should have both an antifungal and antibiotic in the preparation.
The majority of ear infections require 2 weeks of treatment to clear the infection.
Ear medication for dogs that won’t allow you to handle their ears
Although daily ear medications are considered the best for treatment of ear infections. There are some products on the market that are used once or twice only to treat an ear infection.
KC Otopack is a thermally activated gel. It is a liquid when kept cold in the fridge. It is administered inside the ear once a week for two treatments . Once the product warms up to your dog’s body temperature it becomes a gel which is designed to remain in the canal and provide treatment for a week while it slowly dissolves. This gel contains an antifungal medication called Ketoconazole 0.15% and Hydrocortisone 1%.
Claro is another product that is a one time use ear infection treatment. It is labeled for use in dogs with a yeast infection and/or a staphylococcus pseudintermedius ear infection.
About 75% of dogs’ ear infections will resolve using this product. The product is not labeled for use with rod bacterial infections (pseudomonas infections).
What about oral antibiotics or oral antifungal medications? Unfortunately oral medications are not effective at reaching therapeutic concentrations in the ear unless there is severe ulceration present or a suspicion of a middle or inner ear infection. The mainstay of therapy for external ear infections is topical therapy.
How can I treat my dog’s ear infection at home?
Ear cleaning. In a study of dogs with a bacterial or yeast infection, twice daily cleaning with Epi-Otic ear cleaner resolved 68% of ear infections in 1-2 weeks.
Another study of yeast infections in dogs showed nearly 71% of dogs cleared their infection after 7 days of regular ear cleaning with MalAcetic otic.
Most ear medications contain steroids to reduce inflammation and discomfort. A Topical ear solution that contains a steroid like Zymox may be beneficial in an ear infection. The product has not been studied in dogs with perforated eardrums and would have to be used with caution.
Zymox is a product with a weaker steroid (hydrocortisone 0.5% to 1 %) that is sometimes recommended for routine use in dogs predisposed to developing recurrent ear infections.
What not to do when treating your dog’s ears
It is not a good idea to use leftover ear medications in your dog’s ear because you don’t know what type of organism is causing the infection. Some of these medications can also cause damage to your dog’s sense of balance or deafness if there is a perforated eardrum.
Products that contain chlorhexidine, gentamicin and amikacin are the most likely to cause toxicity to the ear with a ruptured or perforated eardrum.
It is also not a good idea to clean vigorously for longer than 1-2 weeks. Over cleaning may cause irritation and inflammation that can perpetuate ear discomfort.
How to clean your dog’s ears:
Completely fill the ear canal with the ear cleanser (don’t worry about over-filling the ear canal! It will just spill out the ear). Then massage the base of the ear for 1 minute. Following this treatment, you can allow your dog to shake their head and then wipe out any excess cleaner with gauze sponge or cotton ball inside the ear flap and the opening of the ear canal. The ear cleanser I recommend is Epi Otic Advanced.
Most veterinarians will recommend once daily to twice weekly ear cleanings as a routine part of treatment for an ear infection. Using an ear cleaner helps to dissolve and remove ear wax and debris to improve penetration of medications instilled into the ear. Following resolution of the ear infection, continued ear cleanings are recommended on a reduced maintenance schedule once to twice a week.
Summary of dog ear infections
The majority of dogs develop ear infections secondary to allergies. The most common ear infection is a yeast infection. However, recurrent or more chronic ear disease tends to promote bacterial infection. Ear cleaning at home and application of topical steroid solutions may be able to treat the infection. However, if symptoms are not improving within a few days it’s best to seek veterinary medical attention.