Overview Of Canine Ear Infections Biology Essay

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Canine ear infections are one of the most common medical reason why pet parents bring their animals to the veterinarian. It is often harder to discover the cause of the infection in dogs compared to humans because the ear canal is shaped so differently. There are three main types, but with all the various reason that could have caused the infection it is still a difficult process. It is important to look for certain symptoms to help distinguish the reasons from one another. The ultimate goal is to seek professional help from a veterinarian. They can do in house testing to confirm a diagnosis and get your four legged friend on the road to recovery. In the end it all comes down to prevention to help your pet live a healthy life.


While working on the job, I have come across many cases of really dirty ears, and I have wondered why they are so common. It has been stated that "without a doubt, one of the most common problems that cross the veterinarians table is otitis externa, or infection or inflammation of the external ear" (Thomas, 1996-2010). I have come to find that there are different kinds of ear infections and different reasons for why they occur.


A canine ear has a different shape compared to a human's ear. A dog's ear is shaped like an L, and dirt and debris tend to collect in the area in the corner of the L. (Foster & Smith, 1997-2010) The dogs ear has two compartments. " Beginning at the opening of the ear canal, the vertical canal travels downward towards the dog's jaw and then makes a 45 degree turn and travels horizontally towards the ear drum, which is why it makes visualization and treatment more difficult" (Thomas, 1996-2010).


There are three known types of ear infections that dogs can fall victim to. These consist of the outer ear infection, also known as the external ear infection, the middle ear infection, and the inner ear infection. Some infections are easier to differentiate from than others, just by looking at the symptoms. The outer ear infection is the most common. If you come across a middle or an inner ear infection they can become more severe than an outer ear infection. No matter what type of ear infection a dog may or may not have, you should always have it checked out by a veterinarian to prevent it from becoming worse. (A Complete Guide for Dog Ear Infections, 2008-2009)


Some breeds develop ear infections more frequently than others. Ear infections are most often found in dogs that have floppy ears. These breeds consist of Labrador retrievers, Basset hounds, Irish setters, Poodles, and the most common, Cocker Spaniels. " As the ear folds, it covers the ear canal and prohibits air from entering and drying the canal resulting in a moist, warm ear canal that is the perfect environment for organisms to grow" (Thomas, 1996-2010).


There are many reasons why dogs can suddenly develop an ear infection, and knowing what caused them can help determine the correct route for curing it. The most common reasons for an ear infection to occur consist of foreign objects, yeast and bacterial infections, mites, tumors, and allergies. (A Complete Guide for Dog Ear Infections, 2008-2009)

Foreign Objects: foreign objects can consist of anything from rocks, leaves, stems, or stones. If there is anything trapped inside a dog's ear it is more likely to cause an ear infection. If a foreign body is found to be the reason of an ear infection it may just need to be flushed out, or in severe cases it may need surgery to be removed. (A Complete Guide for Dog Ear Infections, 2008-2009)

Yeast and Bacteria: Yeast and bacterial infections are usually the most common, but yeast in particular. (A Complete Guide for Dog Ear Infections, 2008-2009) "Malassezia pachydermatitis usually is the culprit and it loves to proliferate in warm, moist environments such as a dog's ear canal" (Thomas, 1996-2010). Bacteria may not be the immediate cause of the infection, but they can definitely worsen the case. A high concentration of bacteria can trigger skin problems that if left untreated could progress into a bad ear infection. (A Complete Guide for Dog Ear Infections, 2008-2009) " Certain bacteria such as Staphylococci, Streptococci, E. coli, and Pseudomonas spp also can cause infections in the ear and in many cases both bacteria and yeast are present" (Thomas, 1996-2010). According to Foster and Smith (1997-2010) "the normal healthy ear has a good defense against these organisms, but if the ear environment changes due to allergies, hormone abnormalities, or moisture, the bacteria and yeast can greatly multiply and break down these defenses."

Ear Mites: These pesky parasites are also known as Otodectes cynotis and are quite common in young puppies. It is very likely that if your dog experiences ear mites, that an ear infection may follow. (A Complete Guide for Dog Ear Infections, 2008-2009)

Tumors: If younger dogs are prone to ear mites, than older dogs are prone to tumors. The tumors usually develop in the wax glands causing a blockage. The only solution if this is the cause of an ear infection is removing it surgically. (A Complete Guide for Dog Ear Infections, 2008-2009)

Allergies: Foster and Smith (1997-2010) have explained that "dogs with allergies, either to food or something they either inhale or that comes in contact with their skin often have ear problems, and the ear problem may be the first sign of the allergy."


Since dogs do not have the ability to literally tell us when something is wrong we have to be able to look for the signs or symptoms ourselves. Dogs will often show signs that are not part of their normal behavior. Some dogs tend to whine while other, more important symptoms to look into include headshaking, tilting their head in an unusual manner, excessive scratching, excessive ear wax with a foul odor, inflammation, redness, and tenderness, and a more severe symptom which includes balance problems. (A Complete Guide for Dog Ear Infections, 2008-2009)

Headshaking: This action shows that the dog is experiencing discomfort and there may be something in their ear that they are try to shake out. Sometimes it can be something as easy as a trapped object or water from previously bathing or swimming. Having a veterinarian look at it can be the difference between a simple solution and a big problem. (A Complete Guide for Dog Ear Infections, 2008-2009)

Tilting of the Head: This behavior can be seen in the same manner as headshaking. It is most likely that they have something in their ear that they are trying to get out of there. (A Complete Guide for Dog Ear Infections, 2008-2009)

Excessive Scratching: Dogs scratch themselves often, but rarely always in the same place unless it is a problem area. It is explained that things that can cause dogs to scratch their ears are "mites, bacterial infections, and skin disorders, all of which cause ear infections in dogs" (A Complete Guide for Dog Ear Infections, 2008-2009).

Excessive Earwax with a Foul Odor: A little bit of ear wax is normal for a dog, but if you notice more wax than normal and it is accompanied by a foul odor this is an important sign. (A Complete Guide for Dog Ear Infections, 2008-2009)

Inflammation, Redness, and Tenderness: These three symptoms play a key role in any infection that a pet is experiencing. If you notice the ear is swollen, hot to the touch, or the dog does not like the area touch when they otherwise do not mind it touched, have a veterinarian examine the ear. (A Complete Guide for Dog Ear Infections, 2008-2009)

Balance Problems: This is a severe symptom. If your experiences balance problems this most likely indicates that it is a more severe ear infection and it should be checked by a veterinarian immediately. (A Complete Guide for Dog Ear Infections, 2008-2009)


Veterinarians would diagnose the problem and be able to tell you either or not it is an ear infection. The veterinarian will also be able to tell how it happened and what will help fix the problem. The veterinarian can use a special tool called an otoscope to look down into the ear canal. This will determine the amount of inflammation, if the ear drum is injured, and what may be causing the infection, such as a foreign body, tumor, or other possible problem. Another way they can determine the cause of the infection is to swab the ear, put it on a slide, stain it, and look at it under a microscope to see if they can find and mites, yeast, or bacteria. It is also wise to take a thorough history during a physical exam to rule out if it could be an allergy or hereditary. (Foster & Smith, 1997-2010)


The course of treatment that is chosen depends on the type of infection. Once the cause is discovered it is important to start treatment right away so the infection does not get worse. " Depending on the extent of the disease, antimicrobial ear drops should be sufficient, otherwise oral medications may have to be added to the water or food of the dog" (A Complete Guide for Dog Ear Infections, 2008-2009). "Antifungal are used for yeast infections Yeast can cause severe ear problems. We usually observe a brown waxy exudate and a bad odor. Daily cleaning of the ears will help, but often these infections are difficult to treat, and special medications need to be given since antibiotics do not kill yeast. Antibiotics are used for bacterial infections. Bacterial ear infections can also have a bad odor and often have a more yellowish exudate. If it is a severe or chronic condition, ear cleaning alone will not take care of the problem and antibiotics will almost always be necessary. Ear mites can cause dry, dark, crumbly debris in the ear that resembles coffee grounds. For this condition, ear cleaning followed by an ear medication to kill mites will eliminate the problem, although the treatment may need to be continued over several weeks depending upon the product used. Allergies are commonly treated with regular ear cleaning with an ear cleaning solution, antihistamines, and fatty acid supplements. Sometimes corticosteroids are needed. These may be given in an oral or injectable form, or they can be applied topically. Glucocorticoids such as dexamethasone are often included in these preparations to reduce the amount of inflammation in the ear" (Foster & Smith, 1997-2010). To help you dog recover at home you clean the ears out with cotton balls, not Q-tips.


Even though ear infections are so common there are ways that you can help to prevent your dog from obtaining one at home. The key to healthy ears is to keep them clean. Check the dog's ears weekly. If your dog swims a lot, has floppy ears, or a history of ear infections, routine cleaning is recommended more often. If the dog gets groomed at a grooming salon you can have the groomer clip excess hair around the ear to allow more air flow. If the dog is a breed that is known to have hair growing in the ear you can have the groomer pluck the ear hair out, which is another way to allow ventilation. Another way to prevent ear infection is to make sure that your dog's ear is dry after every bath. (Foster & Smith, 1997-2010)


Canine ear infections are forever going to be an ongoing battle. With finding this research it has made it more clear to me what they are at least. It has also made it easier for me to know what to do to help prevent them. I can now feel comfortable that when I see what I think may be an ear infection I can recommend the owner to go to their regular veterinarian to have them examine it further.