Common Sources of Ear Problems in Dogs:
https://www.petmd.com/dog/slideshows/6-common-ear-problems-dogs
The discomfort that comes when you have an earache hardly needs elaboration, but imagine for a minute that your ear — inflamed and filled with water or wax — can’t be cleaned or improved by your own hand. You can’t voice your pain or your need for help, either. All you can do is shake your head back and forth over and over until someone notices, diagnoses the problem and administers what is necessary to nurse you back to health. So is the life of your beloved dog when he or she comes down with an ear problem of some kind, and ear problems are extraordinarily common in dogs.

A dog’s external ear canal, where most problems occur, is longer and more vertical than a human’s, making it easier for something like water to make it into the ear canal and stay there. Additionally, a dog’s ear canal is lined with skin and contain glands and hair follicles (just like the skin on the outside of its body), making its ears prone to the same kind of irritants that affect its paws, legs, back and head, said Dr. Christine Cain, DVM and assistant professor at the University of Pennsylvania School of Veterinary Medicine Dermatology & Allergy Service.

Airborne Allergies:
Most canine ear problems stem from an allergy of some type, said Dr. Louis Gotthelf of the Animal Hospital of Montgomery in Alabama and author of Small Animal Ear Diseases. The two most prevalent are airborne and food allergies.

As it is with humans, airborne allergies often occur seasonally, which means that a dog with allergies may be more prone to ear infections anytime from April to September, depending on the allergen (like pollen or grass) that’s causing the reaction.

There are many products available to combat these allergies, but the simplest things owners can do are to bathe their dogs regularly (while taking care to avoid getting water or soap in your dog’s ears while bathing them) and remove the allergen from their environment, if possible, Gotthelf said. “That means walking [your dog] on concrete if he’s allergic to grass or keeping him inside as much as possible during allergy season if it’s pollen in the air that causes him discomfort,” he said.

You may also discuss giving your dog antihistamines with your veterinarian (who can prescribe the appropriate medication and dose), but Gotthelf said that Benadryl and other similar medications only work in about 20 percent of dogs.

Food Allergies:
Food allergies will affect dogs as long as the offending ingredient is a part of their diet and can continue to be bothersome for weeks after consumption. The most common types of food allergies include beef, chicken, eggs and dairy, Gotthelf said, and if an owner suspects his or her dog is suffering from a food allergy, a vet or veterinary nutritionist will likely recommend dietary treatment in conjunction with corticosteroids (steroids to help decrease inflammation and itching) or some other pharmaceutical treatment to keep the dog comfortable.

Dietary treatments for food allergies include a novel protein diet (feeding your dog a protein they haven’t eaten before, like kangaroo, deer or some types of fish) or a hydrolyzed diet, which neutralizes allergens by shrinking down the protein source in a specific food so that a dog’s body can no longer recognize them, Gotthelf said. These diets should be discussed with a veterinarian prior to starting, as most are prescription-based and there are specific protocols pet owners will need to follow in order to rule out a food allergy in their dogs.

Bacterial Infections:
Most of the bacterial infections that affect a dog’s skin (and their ear canals) are strains of staph, Gotthelf said, but they are not the same type that infects humans, so owners shouldn’t worry about them being contagious. There are antibiotic and non-antibiotic treatments for bacterial infections, with the latter being used in chronic cases to prevent resistance.

Non-antibiotic treatments include shampoos with chlorhexidine as well as common bleach, both of which kill the bacteria on the skin, but it’s recommended you try these remedies in consultation with your vet (and avoid using any shampoos inside of your dog’s ear canal). Once treated properly, the infection should clear up within two to three weeks.

Yeast Infections:
Almost all cases of yeast infections in dogs stem from an allergy, as allergies produce an excess of oil on a dog’s skin, including in his or her ears, creating an environment in which yeast can thrive and multiply. Yeast infections can be treated by a combination of systemic and topical anti-fungal medications, Gotthelf said, and like their bacterial counterparts, yeast infections will clear up in about two to three weeks once properly treated.

Mites:
These microscopic insects can drive small animals crazy. Although they’re not the largest source of ear problems in dogs, they can be particularly troublesome for cats, and dogs who live with cats are much more susceptible to ear mites.

According to Cain, ear mites can be treated by anti-parasitic medications applied either systemically or to the ear canal directly. “Secondary infections of the ear canals with bacteria or yeast are common in patients with ear mites, so these may need to be addressed with topical medications and ear cleansers as well,” she said.

Foreign Objects:
Fortunately, cases of foreign objects getting lodged in a dog’s ear canal are pretty rare. Gotthelf said a very small number of canine ear problems he’s dealt with have been related to foreign objects, and when they are, the objects are fairly small, including plant debris, a fly or dried ear medication.

If you suspect your dog has an ear problem or has something stuck in his ear, bring him to your veterinarian for a thorough otic exam. Your veterinarian will use specific tools, like an otoscope, to look at your dog’s entire ear canal and ear drum and properly diagnose the issue. Never use cotton swabs in your dog’s ear, as these can worsen the problem by breaking inside the ear canal, rupturing your dog’s ear drum or pushing the foreign object (or wax) further into the ear canal and against the ear drum.