Ear Diseases and Ear infections in Dogs

Introduction

Ear disease is one of the most common conditions seen in pets. Excessive ear scratching or head shaking, an unusual odor or a dark, crumbly discharge coming out of your dog's ear canal are all signs that something is wrong with your dog's ears. Early treatment of ear problems is important to prevent complications such as damage to the inner ear and hearing loss. Ear problems can have many different signs and many different causes, so a thorough exam performed by your veterinarian is recommended before initiating any treatment. Also, while being the main discomfort affecting your dog, the ear disease could be just a symptom of an underlying condition and not in itself the main cause.

Symptoms

Recognizing the early symptoms of ear disease is the first step towards treatment and relief. Signs of ear problems include:

- Scratching or rubbing of ears and head
- Head shaking or tilting to one side
- Odor from the ears
- brown discharge in the ears
- Redness or swelling of the ear flap or canal
- Hair loss and/or scabs around the ears, head or neck
- Changes in behavior (irritability, aggression)
- Loss of balance, dizziness, lack of coordination (a possible sign of inner ear infection)

What Causes Ear Disease in Dogs?

Dogs can have ear problems for many different reasons. Possible causes include:

Bacterial infections
Yeast infections
Allergies (which in turn may cause secondary bacterial or yeast infections)
Ear mites (which in turn may cause allergic conditions)

Foreign objects (such as plant awns)
Trauma and injuries (insect bites)
Endocrine diseases (hypothyroidism) or weakened immune system
Breed-specific conditions (ear anatomy) and ear environment
Excessive cleaning
Tumors

Allergies
Allergies are a common cause of ear irritation in dogs. Actually, the ear problem is often the first visible sign of the allergy. Allergies can be food-based, airborne (pollens, moulds, plants) or caused by parasites (fleas, or ear mites). Besides scratching their ears, dogs with allergies will often lick their feet and rub their face. Allergies tend to change the environment within the ear causing inflammation and heat in and around the ears, which in turn favor abnormal yeast growth and yeast infections. Certain breeds of dogs, such as Cocker Spaniels, Labrador Retrievers, Schnauzers, and West Highland Terriers, have a higher propensity to develop ear infections for this reason than others.

Parasites
Ear mites, Otodectes cynotis, are a common cause of ear problems in cats, but less common in dogs. Thick reddish brown crusts and dark brown, flaky debris are common in the ears when the pet is infected with ear mites. The mites can be seen when the debris is examined under a microscope. The dog will also often vigorously shake his head or rub his ears. Some dogs will show no signs of discomfort but in most cases the itching will be intense, causing intense scratching and bleeding in and around the ear. That explains why bacterial infections often complicate an ear mite infestation.

Bacterial infections
Allergies and ear mite problems, if left untreated, can lead to additional and more complicated problems, such as bacterial infections. Bacterial ear infections occur when bacteria on the skin work their way into a weakened ear canal. The normal, healthy ear has a good defense against bacteries, but if the ear environment changes due to allergies, hormone abnormalities, or moisture, numerous types of bacteries can greatly multiply and break down these defenses. Symptoms of a bacterial infection vary according to the severity of the condition. A mild ear infection might be implied by an ear that constantly fills with wax, no matter how often you clean it. As the disease progresses from mild, to moderate, to severe, it can result in smelly pus-like drainage from the ear and become extremely painful. Your pet may shake his head frequently, keep his head at a tilted angle, or cry when he scratches his ear.

Yeast infections
Yeast infections can be caused by different yeast organisms. One is Malassezia pachydermatitis, which is a normal inhabitant of the ear in small numbers. Inflammation of the ear, from any of the above causes, allows the yeast to grow in excessive numbers. Other yeast problems involve Candida Albicans, which can be systemic and the root cause of the problem. Yeast-infected ears have a smelly waxy buildup. Far too often when dogs are diagnosed with allergies, they are in fact really suffering from a systemic yeast infection. In that case, antibiotics will not solve the source of the problem. They only address secondary bacterial infections and provide temporary relief from itching.

Trauma and Foreign objects
Dogs that swim or walk in the woods are more exposed to little foreign objects that can enter the ear canal. The presence of plant awns, seeds or burrs in the ear causes irritation, the dog scratches, resulting in a traumatized ear. The traumatized ear is more prone to developing bacterial infections or can exacerbate ear problems. Aggressive cleaning with cotton-tipped applicators can also cause pain and inflammation in a pet's ears.

Endocrine diseases or weakened immune system
Some dogs are more likely than others to experience ear infections for a number of other reasons. Endocrine diseases, for example, causing deficiencies or excesses of various hormones can result in skin and ear problems, too. Thyroid hormone, cortisol produced by the adrenal gland, and sex hormones all influence the quality of the skin and ear environment. Hypothyroidism (thyroid hormone deficiency) and Cushing disease (oversupply of cortisol), just to name two, are examples of these hormonal conditions that may increase a dog's chances of developing ear infections. This is also true of other chronic conditions which weaken the immune system and make an animal more prone to infections.

Breed-specific conditions and ear environment
Certain breed-specific characteristics of dog ears and the surrounding areas can also make a dog more vulnerable to ear infections. One of these characteristics is the particular type of skin or glands located in the ear canal, or dogs with heavy, floppy ears. Dog breeds that most typically suffer from ear infections for this reason include Springer Spaniels, Basset Hounds, Beagles and Labradors. Likewise, some dog breeds are more susceptible to ear infections because of the type and amount of hair present in the ear canal. Infectious agents grow best in warm, humid ears that have little air flow. So, the more hair present in the ear canal, the poorer the airflow and the higher the incidence of infection. Again, there are certain types of breeds that develop ear infections for this reason more often than others. These breeds include Shih Tzus, Lhasa Apsos, Pekingese, and Poodles. Further breeds that are genetically predisposed to otitis include Cocker Spaniels, Labrador Retrievers, Schnauzers, and West Highland Terriers. Thus, all breeds that have very long or very narrow ear canals or dogs that enjoy swimming, will also be predisposed to ear infections.
There are various rare hereditary diseases that occur in different breeds or lines and affect the ears. These include dermatomyositis in Collies and Shetland Sheepdogs, and primary seborrhea in Shar Peis and West Highland White Terriers. Squamous cell carcinomas, melanomas, and other tumors can be seen in the ears.

Excessive cleaning
Overzealous ear cleaning or excessive bathing can also increase your dog's risk of developing ear infection.

Diagnosis

Because there are many potential causes of ear problems, a complete exam will often be needed to determine their origin. Just dispensing antibiotics may relieve the symptoms in most cases, but not necessarily treat the ear disease. To perform a more thorough exam, your veterinarian can use an otoscope to look down into the ear canal and determine the amount of inflammation present, if the ear drum is damaged, and if there are any foreign bodies, tumors, or other potential causes of the problem. A sample of the ear discharge can be tested for bacteria, yeast, and mites. A thorough case history and physical exam may help determine if the condition could be a hormonal, allergic, or hereditary in nature. If a bacterial infection does not respond to the first antibiotic therapy, a culture and sensitivity test may be needed to select the proper antibiotic.

Treatment

The type of treatment is going to depend on the cause and location of the ear disease and what secondary conditions developed as a result. Antibiotics are used for bacterial infections and antifungals for yeast infections. Glucocorticoids such as dexamethasone are often included in these preparations to reduce the amount of inflammation in the ear. When an underlying condition is causing the development of ear infections in a pet, that condition will also need to be treated. A hormone abnormality or allergy must include a therapy that treats the whole dog, such as hormonal replacement or allergy testing and hyposensitization (immunotherapy). This will help to control and prevent future incidents of otitis. In addition, there are certain homeopathic remedies available that can help to alleviate your dog's painful and irritating symptoms. These products often include natural ingredients such as Tea Tree oil, chamomile, marigold, and myrrh, which contain many properties that may help relieve pain, irritation, and inflammation.

In case of ear infections, oral treatment alone will often not be sufficient and additional treatment in the form of medicinal drops or ointments will have to be administered over a period of time. Always apply local medication on perfectly clean and dry ears. It's very important to continue the treatment for the prescribed length of time in order to effectively clear up and put an end to the infection.

If foreign bodies or parasites are present in the ear and are the cause of the infection, these may have to be removed while the dog is under sedation. Sedation may also be required if a thorough cleaning and flushing of the canine patient's ears is needed.

Because of the complexity of ear conditions and the wide array of possible causes and secondary conditions, no course of treatment should be pursued without first consulting a qualified veterinarian.

Preventing ear disease

Regardless of the cause of the ear disease, the key to healthy ears is to keep them dry and clean. It is more important to check your dog's ears regularly for dirt and discharge than it is to clean them. Normal ears of dogs and cats have a relatively smooth inner lining with a slight amount of wax buildup. If the ears have a bad smell or the ear canals look very abnormal and your dog is showing severe discomfort do not delay in contacting your veterinarian. If your dog has a ruptured or weakened eardrum, some ear cleansers and medications could do more harm than good. Should the ears need cleaning, use only products and methods recommended by your veterinarian. Cotton applicator swabs can be used to clean the inside of the earflap and the part of the ear canal you can see. Never clean any deeper than you can see, since that tends to pack debris in the ear canal, rather than removing it.

If your dog swims a lot, has flappy ears, or a history of ear disease, weekly cleaning is recommended. In 'problem breeds' (see above), excess hair around the ear can be clipped to allow more air flow. Any underlying condition that predisposes your dog to ear problems should be treated.

For more information on ear diseases and ear infections, contact your local veterinarian.