Common Causes of Dog Ear Infections

The Anatomy of the Canine Ear

A dogs ears are the same as a persons ears in that their main function is hearing. Dog ears just do not look like peoples ears. The outside part of the ear is called the pinna. In some dogs it is floppy (like a Basset Hound) and in some dogs it stands up (like a Corgi). The pinna helps to funnel sound into the ear canal. Whereas people have a straight ear canal, the ear canal in the dog is a little L shaped. It is made up of the vertical (descending) canal and the horizontal canal. The horizontal canal ends at the eardrum, or tympanic membrane. The eardrum is a transparent membrane that separates the external ear from the middle and inner ear.

The Common Factors that Cause Canine Ear Infections

The most common is an infection of the outside of the ear including the horizontal and vertical canals. This infection is referred to as Otitis Externa and is caused by three main reasons; ear mites, bacteria and yeast.

Otodectes cynotis or ear mites are the cause of this ear infection. It is most commonly found in puppies, but can be contracted at any age. It is highly contagious and is transferred from one infected animal to the next. These mites can also live on the head and neck.

The bacterium most commonly involved in ear infections is Staphylococcus and the yeast most commonly seen is Malassezia. Bacterial and yeast infections are more common in dogs than ear mite infections. Even though there are only a few causes of ear infections, many things predispose a dog to getting an ear infection. Some of the most common predisposing factors are:

Ear canal conformation – Ear canals that are very small or longer than normal retain debris and moisture that can lead to an ear infection.

Over Abundance of Hair in the Canal – This excess amount of hair is the perfect tool for trapping debris and holding onto water which can lead to an infection.

Swimming or living in humid areas – Water retained in the horizontal canal after swimming can lead to an ear infection. In humid climates, water from the air may accumulate in the ear canal leading to an ear infection.

Floppy or Folded Over Ears – Pinnae that cover the vertical canal can trap debris and retain water which results in ear infection.

Food Allergy – When a dog is allergic to certain foods, skin reactions can occur as well as changes in the ear canal environment. When this occurs, water is retained and the ending result is an ear infection.

Seasonal or Inhalant allergies (atopy) – An allergic response to grass, trees, mold, dust, etc. can change the environment of the ear canal leading to moisture build-up and an ear infection. Dogs with seasonal allergies will usually have other skin problems, too.

Systemic Diseases – Some diseases of the endocrine system, such as hypothyroidism, change the environment of the skin and decrease the ability of the immune system to fight off infection. The combination of these things can lead to ear infection.

A growth or foreign object in the ear – A growth or foreign object in the ear can trap water and debris in the ear canal leading to an infection.

Cleaning the ears too much and leaving water or cleanser in the ears may also predispose a dog to getting ear infections.

Heather Fox is an experience veterinarian who loves to write and share about her experience and knowledge about job. She started an online classroom at Clivir.com where she provide more information about Dog Flea Allergy Dermatitis Symptoms and Dog Urinary Tract Infections Symptoms.

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