Were You Smarter Than a Vet Student About Ear Infections?

Thanks to everyone who took this ear infection quiz. Congratulations to Arlene Millman of Huntington, New York, winner of the book drawing. She’ll be receiving a copy of Speaking for Spot!

Below are the correct responses to the quiz questions along with explanations. I hope you learn something new!

1. Ear infections can be caused by:
2. Allergies
3. Water in the ear canals
4. Hormonal imbalances
5. All of the above

Most ear infections have an underlying predisposing cause that alters the health of the ear canal thereby setting the stage for yeast or bacteria to set up housekeeping. A moist environment within the ear canal is one such predisposing cause. Hormonal imbalances and allergies can cause inflammation within the lining of the ear canals which can result in secondary infection.

2. Which of the following is not a cause of ear infections?
3. Yeast
4. Foreign bodies
5. Viruses
6. Tumors

Anything that disrupts the normal architecture of the ear canal, such as a tumor or foreign body, can result in secondary infections. Those of you who live west of the Mississippi are likely familiar with foxtails, far and away the most common foreign body to land in a dog’s ear canal. Yeast organisms thrive in warm moist environments, and are a common cause of canine ear infections. Viruses are not a cause of ear infections.

3. Ear mites are common in
4. Adult dogs
5. Adult cats
6. Kittens and puppies
7. Feral cats

Ear mites are readily contagious with close contact, so it makes sense that they are common within feral cat colonies. While ear mites do occur in dogs and cats of all ages, these creepy crawlies are a relatively uncommon cause of ear infections.

4. The cause of an ear infection can be reliably determined by
5. The appearance of the discharge
6. The odor of the discharge
7. An otoscopic exam (looking in the ear canal with an otoscope)
8. None of the above

Microscopic examination of discharge from the ear canal is the very best way to diagnose whether an infection is caused by yeast, bacteria, or mites. This determination cannot be made simply by smell or visual inspection.

5. Infection-associated tears in the eardrum (tympanic membrane)
6. Are very uncommon
7. Dictate a change in treatment strategy
8. Cause deafness
9. Are typically very slow to heal

Infection-associated tears in the eardrum are relatively common. When this is the case, it’s presumed that there is also infection within the middle and inner compartments of the ear, a condition referred to as otitis media interna. These tears tend to heal rather quickly. The tear itself does not typically cause deafness, but chronic inner ear infections certainly can. Finding a tear within the tympanic membrane definitely changes treatment strategy compared to finding infection only within the external ear canal. For example, systemic rather than just topical antibiotics might be used and ear cleaning is avoided for fear of flushing debris deeper into the middle and inner ear compartments.

6. Patients with recurrent or chronic ear infections are sometimes referred to:
7. A veterinarian who specializes in dermatology
8. A veterinarian who specializes in neurology
9. A veterinarian who specializes in surgery
10. Any of the above

Referral to a veterinary specialist makes really good sense when ear infections recur frequently, cannot be resolved, and/or lead to other abnormalities. Given that the lining of the ear canal is an extension of the skin, referral to a dermatologist (skin doc) is a logical choice. If the ear infection affects the inner ear and neurological symptoms such as a head tilt or dizziness develop, help from a neurologist may be recruited. A veterinarian who specializes in surgery may be called upon to either open up or entirely remove the external ear canal. These are last resort treatments, used when the ear canal has become profoundly scarred and narrowed as a result of chronic inflammation.

7. Which of the following is not a potential strategy for preventing ear infections?
8. Regular ear cleaning
9. Regular swimming to help flush out the ear canals
10. Ear canal surgery
11. Feeding a special diet

Food allergies can create ear canal inflammation that sets the stage for infection, hence the need for a special diet. Regular ear cleaning works well to manage some dogs and cats with recurrent ear infections. As mentioned in question 6, surgery is used to treat some animals with severe ear canal changes caused by chronic inflammation. Water deposited in the ear canals as a result of swimming can be a cause of recurrent ear infections for some dogs. It is never considered a preventive strategy.

8. Which one of the following statements is true?
9. The treatment for ear infections is typically the same regardless of cause.
10. Most ear infections are contagious from one ear to the other.
11. Most ear infections arise because of some other underlying issue.
12. Ear infections invariably cause scratching at the ears and/or head shaking.

The treatment strategy for ear infections varies from patient to patient depending on the type of infection present as well as its underlying cause. Other than ear mites that trundle over the top of the head from one ear to the other, ear infections are not considered to be contagious from ear to ear. Because both ear canals are typically impacted by the same underlying issue (water in ear canals, allergies, hormonal imbalances, etc.) that sets the stage for infection, it makes sense that both ears are often affected. Lastly, while head shaking and ear scratching are common indicators of an ear infection, not all dogs and cats demonstrate these symptoms.

Have these answers surprised you? Have you learned anything new?

Best wishes,

Nancy Kay, DVM

Diplomate, American College of Veterinary Internal Medicine
Author of Speaking for Spot: Be the Advocate Your Dog Needs to Live a Happy, Healthy, Longer Life
Author of Your Dog’s Best Health: A Dozen Reasonable Things to Expect From Your Vet
Recipient, Leo K. Bustad Companion Animal Veterinarian of the Year Award
Recipient, American Animal Hospital Association Animal Welfare and Humane Ethics Award
Recipient, Dog Writers Association of America Award for Best Blog
Recipient, Eukanuba Canine Health Award
Recipient, AKC Club Publication Excellence Award
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Please visit http://www.speakingforspot.com to read excerpts from Speaking for Spot and Your Dog’s Best Health.   There you will also find “Advocacy Aids”- helpful health forms you can download and use for your own dog, and a collection of published articles on advocating for your pet’s health. Speaking for Spot and Your Dog’s Best Health are available at http://www.speakingforspot.com, Amazon.com, local bookstores, and your favorite online book seller.