Causes of Ear Infection
A dog’s ears can become irritated for many reasons, from the outer edge of the ear flaps to the inner ear and at any place along the way. For purposes of this article, we will use the terms “ear inflammation,” “ear irritation,” “ear infection” and “ear problems or disorders” interchangeably. Our goal is to provide an overview of the things that commonly cause ear discomfort in dogs.
Parasites – Parasites can cause tremendous ear irritation. Fleas that infest a dog’s ears are particularly disturbing and can cause tissue erosion in addition to intense itchiness, which leads to scratching and self-inflicted wounds. Mange mites, including otodectic, demodectic and/or sarcoptic mites, often settle in ears, causing hair loss, itchiness and inflammation. They can also contribute to waxy build up in the ear canal.
Foreign Objects – Foreign objects that get into the ears are another common cause of irritation, inflammation and infection. Ticks, seeds, grass awns, foxtails and other plant material can cling to the skin and hair around the ear openings and work their way down the L-shaped outer ear canal, where they often become lodged because of that canal’s shape.
Climatic Conditions – Weather extremes, especially unusually hot temperatures and high humidity or freezing cold conditions, are other key contributors to ear problems. Moisture and heat create a rich habitat for yeast and bacterial proliferation, and icy weather can cause frostbite.
Allergies – Allergies are often associated with ear discomfort. Allergic reactions can be caused by food allergies, inhalant allergies, contact allergies or adverse reactions to external parasites – especially fleas.
Infections – Infections are caused by the invasion and replication of microorganisms. Yeast and bacterial ear infections are especially common in dogs. Infections often occur in dogs with long droopy ears and in those living in hot, humid environments. Outer ear infections can move into the middle and inner ear.
Aural Hematomas - Secondary ear problems can develop if the underlying cause of an ear disorder is not addressed. Most dogs with irritated ears scratch and shake their heads to try and relieve itchiness and discomfort. This can physically damage sensitive ear tissue and cause blood-filled blisters, called aural hematomas, on the ear flaps. Abscesses can also occur, especially after dog fights.
Trauma – Mechanical trauma, whether caused by blunt force, bite wounds, excessive sunlight exposure, frostbite, contact with corrosive chemicals or otherwise, can cause ear problems.
Tumors – Polyps, tumors of the glands that make ear-wax (ceruminous glands) and other ear masses can cause inflammation and discomfort and also adversely affect hearing and balance.
Canine Vestibular Syndrome - Canine vestibular syndrome is an ear disorder that occurs mainly in older dogs but occasionally appears in younger animals. While its cause is unknown, this disease causes balance problems, dizziness, vomiting and difficulty eating or drinking.
Stenosis – Stenotic ear canals are abnormally narrow. This increases the chance of trapping moisture, dirt and other debris.
Preventing Ear Infection
Dogs exposed regularly to wet environments should have cotton balls or other soft padding placed into their ears to reduce the influx of moisture. If water does enter the ears, they should be dried gently. Topical drying agents can help but should not be used if the eardrum has ruptured. Routine ear cleaning is not normally required, unless a dog is prone to developing waxy build-up. When cleaning is appropriate, owners should avoid using irritating substances like alcohol, ether or hydrogen peroxide. Owners shouldn’t insert cotton swabs (“Q-Tips”) into their dog’s ears, as this can force debris down the ear canal and contribute to ear infections. It also can cause the ear drum to rupture.
Parasitic ear disorders are best prevented by eliminating contact with parasites. Allergies and other causes of ear problems must be addressed on a case-by-case basis.