Introduction – The Anatomy of the Canine Ear

Just as with humans, a dogs ears mainly function for hearing. The difference is the appearance. The outside part of a dogs ear is referred to as the Pinna and is sometimes floppy like a Basset Hound or straight like a Corgi. The main function of the pinna is to funnel sound into the ear canal. While human ear canals are straight, dogs are shaped like the letter “L”. The ear canal is made up of the vertical or descending canal and the horizontal canal. The latter canal ends at the eardrum or tympanic membrane. In a dogs ear the eardrum is a clear membrane and separates the external middle an inner ear.

Common Causes for Ear Infections

Otitis Externa is the most common ear infection in dogs. The three main causes are ear mites, bacteria and yeast and it affects the external part of the ear including the horizontal and vertical canals.

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.

Staphylococcus is the most common cause of bacteria related ear infections. Malassezia is the most commonly seen cause of yeast related ear infections. These two types of infections are seen more frequently than ear mite infections. However, there are predisposing factors that make your dog susceptible. They include:

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 Ear Canal Hair – When there is too much hair in the ear canal, it tends to trap debris and retain water which leads to ear infections.

Swimming and Humid Areas – If a dog loves to swim, he/she can have water trapped in the horizontal and vertical canals which leads to infection. In addition, if a dog resides in a humid climate, the ear can retain moisture from the air, thus resulting in an 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.

Allergies to Food – Not only will food allergies cause skin problems; they can also alter the environment of the ear canal. When this happens excess moisture is retained and results in ear infections.

Seasonal or Inhalant Allergies – This is also known as Atopy. If a dog has an allergic reaction to grass, trees, mold, dust and other environmental factors it can affect the environment of the ear canal. When this occurs, moisture accumulates creating an ear infection along with skin afflictions.

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 – 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.

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

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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.

Common Causes of Dog 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.

Ear Mites or Otodectes cynotis cause these ear infections. While they are most commonly found in puppies, any dog at any age can get them. They are contracted by exposure to other animals infected with them and can live on the head and neck as well.

Malassezia is the most common cause of a yeast related ear infection while Staphylococcus is the most seen factor in bacteria related ear infections. These two forms are generally more common than ear mite infections; however there are predisposing factors that can make your dog vulnerable. These factors include:

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.

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 and Humid Areas – If a dog loves to swim, he/she can have water trapped in the horizontal and vertical canals which leads to infection. In addition, if a dog resides in a humid climate, the ear can retain moisture from the air, thus resulting in an infection.

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

Food allergies – An allergic response to a particular food ingredient can change the environment of the ear canal leading to moisture build-up and an ear infection. Dogs with food allergies may have other skin problems, too.

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 – Diseases that affect the endocrine system such as hypothyroidism can affect the skin and the immune system. When both of these systems are compromised, an ear infection can occur.

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 share her knowledge about Dog Illness Diagnosis. She has an online classroom at Clivir.com where you can find more of her articles about Ear Infections in Dogs.

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Shaking of the Head

Scratching at the head or ears

Continuous rubbing of the head and ears on the ground or floor

A distinct redness or irritation in the ear canal

Discharge coming from the ears

A brown or yellowish discharge present in the ears

Foul smell emanating from the ear

Pan when ears are petted or touched

The Veterinary Visit – Diagnosis of an Ear Infection

At the first sign of symptoms an appointment should be made with a veterinarian. It is also important to remember that you should never put anything into your dogs ears before seeing the veterinarian. This could result in additional symptoms including neurological which include head tilting and walking in circles.

For dogs that get repeated ear infections or have infections that will not go away with treatment, it is important to find the underlying cause of their problems. Some things are easy to figure out just from a physical examination. If a dog has a lot of hair in its ears, floppy pinnae, or small ear canals, a visual examination will show this. Tumors and foreign objects in the ear can usually be seen during a physical examination, too.

In order to rule out an allergy to food, the veterinarian will put your dog on a hypoallergenic food for a period of about eight weeks. During this time you will monitor your dog and keep a journal of any receding symptoms, increasing symptoms or no change in symptoms at all.

Skin and blood testing is used to rule out Atopy. This word stands for seasonal and inhalant allergies. The test will provide the veterinarian with exactly what your dog is allergic to, if anything.

Hypothyroidism and other endocrine diseases affecting the skin are usually diagnosed through a series of one or more blood tests which test the function of a particular endocrine organ. Usually dogs with endocrine disorders will have other symptoms besides ear infections that will lead the veterinarian to suspect another problem.

Treatment of Ear Infections

Once the underlying cause is determined, the treatment can begin. For dogs with food allergies, avoiding these foods is paramount. In dogs with seasonal and inhalant allergies, a combination of medications including antihistamines, omega-3 fatty acid supplements and cyclosporine will be prescribed and your dog will most likely be required to take them for the rest of his/her life.

In addition, topical treatments, antibiotics, antifungals, shampoos and rinses may also be required. However, each dogs case is different and will depend on the severity of their allergy.

In general, an ear infection can be cleared up with a combination of oral medication and medication inserted in the ear. However, it is imperative that you clean your dogs ears once or twice a week to remove excess buildup of medication which can retain debris and impede the healing process. An ear infection is usually treated for two weeks, although some cases may take longer. If the infection does not clear up, a swab or ear culture may be needed for further testing.

How to Prevent Ear Infections

Treat all underlying diseases

Dry your dogs ears out after a bath.

Dry your dogs ears out every time it swims.

Do not use water or cleaner inside your dogs ears unless absolutely necessary and always make sure to dry them thoroughly

Remember: Keeping your dogs ears dry is the one key element in preventing as well as treating ear infections.

An experience veterinarian with great passion for writing, Heather Fox loves to share her knowledge about Dog Health Symptoms with fellow pet lovers. You can find more of her lessons including Dog Flea Allergy Dermatitis Treatment on Clivir.com.

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