Common Causes of Dog Ear Infections
Friday, 18. September 2009
The Anatomy of the Canine Ear
Dogs, just like humans have ears that function to hear sounds in the environment. The difference is that while the outside of a human ear is straight, a dogs ear can be floppy or straight. This area is referred to as the Pinna. Its main function is to funnel sound into the ear canal. A dogs ear canal is “L” shaped while a humans is straight. A dogs ear canal is made up of the descending canal or vertical canal and the horizontal canal which ends at the eardrum or tympanic membrane. A canine eardrum is clear and separates the external, middle and inner ear.
Common Causes of Dog Ear Infections
The most common ear infection in dogs is an infection of the external part of the ear including the horizontal and vertical canals. This type of infection is called otitis externa. Otitis externa in dogs is really only caused by three things, namely ear mites, bacteria and yeast.
Ear mite infections are caused by the mite Otodectes cynotis. Ear mite infections are seen more in puppies than adult dogs, but any dog can get ear mites. A dog gets ear mites from other infected dogs. Ear mites can live in the ear and 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:
Malformed Ear Canal – When a dogs ear canal is too long or too small, this provides ample opportunity for moisture and debris to become trapped leading to an infection.
Excessive hair in the ear canal – Excess hair in the ear canal can trap water and debris leading to an ear infection.
Residing in Humid Climates or Swimming – In a humid environment, water from the air can become trapped in the ear. In addition, a dog that swims can end up with water retained in both the horizontal and vertical canals, both of which can lead to infection.
Folded or Floppy Pinna – If the pinnae are folded over or cover the vertical ear canal, debris and water can become trapped, thus resulting in 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.
Inhalant and Seasonal Allergies – These are also referred to as Atopy and include reactions to dust, mold, trees, grass and other environmental factors. Not only will your dog experience skin irritations, the environment in the ear canal will change resulting in moisture buildup which then leads to ear infections.
Systemic Disease – Hypothyroidism or other diseases that affect the endocrine system hamper the immune systems ability to fight infection. When both of these afflictions occur, an ear infection is inevitable.
A Growth or Foreign Object – If there is an abnormal mass or some kind of foreign particle in the ear, it can trap debris and moisture causing an ear infection.
Over Ear leaning – If a dog’s ears are cleaned too often, excess water and cleanser can be left behind. These two things can trap debris and eventually lead to an ear infection.
Heather Fox is an experience veterinarian who loves to share her knowledge about Dog Diseases Symptoms. She has an online classroom at Clivir.com where you can find more of her articles about Dog Ear Infections Causes.