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Guide to Dog Ear Illnesses

Table of Contents

Summary:

"Dog Ear Illnesses have many causes including:

  • Bacteria
  • Fungus or yeast
  • Changes in the structure of the ear
  • Parasites
  • Food or environmental hypersensitivity or allergy
  • Treatment errors

Symptoms are often described as being Otitis Externa, which is inflammation of the external ear canal (includes the pinnae or ear itself, ear canals and external wall of the tympanic membrane), or Otitis media, which is inflammation of the middle ear. The middle ear includes the wall of the tympanic membrane, bulla (tympanic cavity), auditory ossicles and the auditory tube.  If a dog has balance problems, vestibular disease can be the cause, which is a problem in the inner ear and the way that information is coordinated with other senses and communicated to the brain.

Dog Ear Anatomy

Inflammation in the ear is the result of a problem with the normal ear environment. For example enlarged glands (the ear is lined with cerumen glands) or excessive wax can cause inflammation. Problems in the middle ear often start in the outer or external ear. Otitis externa is the most common diagnosis with bacteria or yeast being the cause. The infection perpetuates the ear problem and if not treated, can lead to changes that can affect ear health and hearing.

Some breeds such as those with pendulous ears (Spaniel and Retrievers), with hair lined ear canals (Terriers and Poodles) or narrow ear canals (Shar pei) are prone to ear infections. This is also true for dogs that live in humid climates. Treatment is usually with select drops and antibiotics.

In some cases surgery is necessary to either resolve a dog ear problem (tumors, injuries) or as a complement to the use of medications.."



Overview

There are two main types of dog ear illnesses: infections of the outer ear (otitis externa) and infections of the middle ear (otitis media). Most ear illnesses begin in the outer ear and are caused by either a bacterial or a fungal infection. Often only one ear is affected. Infections may spread from the outer ear into the middle ear. Improper cleaning or foreign bodies in the ear may rupture the ear drum, also spreading infection to the middle ear.

Dog ear illnesses are first evaluate based on the probably cause of the problem. This is based in part on the location of the problem on the ears.

Location and Common Causes of Dog Ear Illnesses

Breed

Location of Dog Ear Symptoms

Pinnae (part of the ear that extends from the dogs body to the tip of the ear)
Pemphigus folaiaceus, vasculitis (inflammation), scabies, food reaction, atopy
Otitis Externa (problem in the upper part of the ear and canal)
Bacterial and fungal infections, endocrine disease, polyps, parasites, food reaction, atopy


Ear infections may also be caused by ear mites (). Ear mites, when present, are generally present in both ears. They are easier to treat than many other types of infections. A single cleaning with a medicated solution often does the trick. If your dog has mites, be sure to clean the area he or she lives in with a miticide such as

Breeds Prone to Dog Ear Problems

Some pets are more susceptible to dog ear illnesses than others. This includes breeds with:

  • Pendulous ears
    • basset hounds
    • cocker spaniels
    • retrievers
  • Hairy Ears (Hirsute external canals)
    • Terriers
    • Poodles
    • Schnauzers
  • Narrow Ear Canals
    • Shar-pei

Common Dog Ear Illnesses

Common Dog Ear Illnesses

Causes

Description of Dog Ear Problem

Allergy or Hypersensitivity to Food
A dog may or may not be allergic; commonly a reaction against a protein, rarely an additive; clinically indistinguishable from atopy, which is inflammation caused by an environmental allergy.

The condition is treated with an elimination diet, where the diet is reduced to a simple protein and carbohydrate such as chicken and rice. Once improvement is seen ingredients are added back in until the culprit can be determined.  Symptoms are treated with antihistamines, the addition of fatty acids to the diet and glucocorticoids for inflammation.
Atopy (hypersensitivity to allergens in air)
Atopy is a hypersensitivity to aeroallergens such as pollens, house dust mites, or mold spores. Allergy related problems could vary with the change in seasons.

Dog ear atopy is diagnosed using a dog's history, a physical exam and by ruling out other possible causes for the condition. The veterinarian might perform an allergy skin test to identify the specific allergen that is causing the problem.

Treatment can include allergy shots to reduce the level of sensitivity (called immunotherapy), adding fatty acids to the diet and topical glucocorticoids to reduce inflammation.

Dogs treated for atopy has a good prognosis with treatment, although the condition often cannot be cured.

Dog Ear Atopy

Changes to Ear Structure and Hair
The ear canal can narrow (stenosis) as the result of several conditions, trapping debris in the ear. Conditions include cerumen gland hyperplasia (too many normal cells formed in the ear) and the formation of polyps.

Excessive amounts of hair could block the ear canal causing moisture buildup and related dog ear illnesses.
Ear Infections
There are two types of dog ear infections, those cause by bacterial and other that are caused by yeast or fungus. When the problem occurs in the outer or external ear, it is referred to as Otitis externa. Depending on the cause, it can be a challenge to treat, although in most cases, cleaning the ear canal and applying medications will cure the problem.

Medications used include an antibiotic or antifungal agent as well as a glucocorticoid to address the inflammation. The glucocorticoid also changes the secretion in the glands that line the ear canal, creating an unfavorable environment for the infectious agent to multiply in numbers.  Most medications are applied as drops since the liquid is easily distributed in the ear canal.

If a dog ear infection is left untreated, it can spread to the otitis media or inner ear, causing problems such as a thinning of the tympanic membrane. Problems such as ulceration can extend all the way to the eardrum.

Once the disease progresses to this point, it is more difficult for the veterinarian to break the cycle of inflammation, ulceration, infection and issues which start to destroy surrounding structures in the ear. Over time hearing can decline such as the inability to hear high pitched sounds. A dog can experience pain as well.

Problems can occur if the eardrum ruptures allowing infectious agents to spread to the other side. Once treated a veterinarian has to make sure that the eardrum doesn't heal before the infection is eliminated, or it can become trapped.

Foreign Bodies
During the spring and summer grass seeds or plant awns are a common cause, particularly in breeds with longer hair around the ears. The foreign body is found during an in office examination using a device called an otoscope.  Once the foreign body is removed, ear health should be restored.
Genetics
There are several inherited problems can result in dog ear illnesses and abnormalities. These include:
  • Stenosis: a constriction or narrowing of the ear duct
  • Hirsutism: heavy hair growth which blocks normal air flow into the ears or that traps moisture
  • Ears that restrict air flow into the ear canal (see list above)
Hyperadrenocorticism (spontaneous or idiopathic)
The spontaneous form of hyperadrenocorticism or Cushing's Disease is an excessive production of glucocorticoids either due to a microadenoma (small tumor) or macroadenoma (large tumor) of the pituitary gland or due to adrenocortical neoplasms (non cancerous tumor that forms from the cells lining the outside of a tumor.

The condition is diagnosed with several blood tests and a urinalysis. X-rays are used to check the adrenal glands and for osteoporosis. Ultrasound can also check the adrenal gland.

Medications are used to treat the disease depending on the type of hyperadrenocorticism diagnosed.  It may be necessary to remove the adrenal gland if tumors are present (neoplasia).

The prognosis for 60% of dogs with adrenal tumors is a life expectancy of 36 months.
Hypothyroidism
Hypothyroidism is caused by insufficient production of thyroid hormone. Diagnosis is reached using blood tests and thyroid tests for free T4, total T4 and TSH assays among others.

Hypothyroidism in dogs is treated with hormone replacement therapy. The prognosis is good for dogs that achieve remission by taking the recommended medications.
Keritinization Disorders
Keritinization disorders in the ears turn  normal squamous skin cells into a horny material such as nails.
Medication
Certain topical drugs can irritate and injure the ears. Abrasive cleaners can also cause irritation.
Moisture
Moisture in the ears can create the conditions that lead to bacterial infections. This can occur as the result of swimming, the use of the wrong dog ear cleaning products, living in a high humidity environment and dog owners that clean the ears too often.
Neoplasia (tumors)
Neoplasia is the abnormal proliferation of cells in the ear can cause an obstruction. Other types of obstructions are polyps cerumen gland hyperplasia (increase in the number of normal cells in the glands that line the ear).

Dog ear tumors are diagnosed with an examination using an otoscope. Treatment involves surgical removal of the cancerous area. The prognosis is good if the cancer is completely removed.
Parasites
Several types of parasites can cause dog ear illnesses. This includes:
  • Otodectes cynotis (ear mites): Looks like coffee grounds in the ears. The mites are diagnosed via an examination in the veterinarian's office with a tool called an otoscope.

    The veterinarian will evaluate ear debris under a microscope to confirm the diagnosis.  The condition is treated with a medication that kills parasites using an oral or topical medication.

  • Scabies: dog ear scabies are a highly contagious disease caused by Sarcoptes scabie var.canis in dogs also known as parasites or mites. The disease usually effects the edges of the ears as well as the ear canal.

    The veterinarian will diagnose the condition after examining superficial skin scrapings. If scabies are suspected, a positive reaction to treatment will confirm the diagnosis.  Antiparisitic agents are used to treat the condition.

    Dog Ear Scabies

    Dog Scabies Picture Ear
  • Otobius megnini: a soft bodied tick
Pemphigus foliaceus (immune-medicated skin diseases)
The skin disease Pemphigus foliaceus causes blistering on the ears. The condition can be induced by drugs or as the result of a tumor. The condition often occurs on the inner surface of the ear.

Pemphigus in the ears is diagnosed using a biopsy. The condition is treated with immunosuppression drugs.  The prognosis is fair with treatment. If the pemphigus was caused by a medication your dog is taking, making a change results in an excellent prognosis.

Pemphigus Foliaceus in Dog Ear

Seborrhea (idiopathic seborrhea)
Idiopathic seborrhea (unknown cause) is the excessive formation of ear wax. It causes an abnormal change in the cell renewal time, causing too many skin cells to form.

The condition is diagnosed with a biopsy.

Dog ear seborrhea is treated with ear cleaners and corticosteroids and retinoids. The prognosis is guarded for dogs with this condition.
Vestibular Disease
In dogs, the vestibular or inner ear provides the dog's brain with information on body position. It informs the dog if it is turning, falling, or speeding up. This information coordinates with information from the eyes and other sensory information such as touch to help a dog maintain balance.

Dog With Vestibular Ear Problem


Dog Vestibular Disease Patient that "couldn't walk straight."


Symptoms of dog vestibular disease:
  • stumbling
  • lack of coordination
  • staggering
  • head shaking
  • motion sickness
  • vomiting
  • sleeping on hard surfaces instead of bed
Treatment depends on the underlying cause/diagnosis. It can caused by a treatable inner ear disorder such as a dog ear infection or it is possible that the cause cannot be determined, called idiopathic vestibular disease.

Brochures and References:

Brochures on dog ear illnesses referenced on this page:

(PDF Download) by
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For additional reading on Dog Ear Illnesses and Problems:

Diseases of the Outer Ear
Haar, G. Ter DVM

The Patient with Otitis Externa
R. S. Mueller
Department of Clinical Sciences Coll. of Veterinary Medicine &
Biomedical Sciences
Colorado State University, Fort Collins, CO, USA.

Dog Ear Illnesses Researched by:

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