By Scott Rizzo,DVM,MS, DACVIM
When I share with others that I am a veterinary dermatologist, many are intrigued with the novelty. I wholeheartedly profess to have a unique occupation. There are fewer than 200 board-certified veterinary dermatologists in theUnited States. A few people are inclined to quip, “How many dogs get acne, anyway?” In short, very few! Despite this, dermatologic conditions are one of the most common reasons owners present their pet to their veterinarian.
The discipline of veterinary dermatology involves diagnosis and treatment of skin disease in animals. Interestingly, veterinary dermatologists are also otologists, diagnosing and treating diseases of the ear. This relationship is borne out of the fact that many diseases of the skin on the body may also manifest within the ear or on the ear flap.
Otitis externa is a common condition of dogs and cats. It is inflammation and/or infection of the ear, and is limited to the area from the ear opening to the ear drum. Without doubt many readers have had a dog or cat with signs of otitis externa, and have appropriately taken him or her to their family veterinarian. Typical signs of otitis externa include scratching, rubbing, and shaking of the head. Redness and discharge are often present. Infections can be quite painful, and can lead to head shyness, decreased activity and decreased appetite. Some dogs that violently shake their head may also develop a painful and acute swelling of the ear flap, termed an aural hematoma.
The causes of otitis externa are many. Bacterial and yeast infections of the ear are often present. Although microscopic identification of exudates and treatment of infections is very important, it is important to recognize infections are the result of a primary cause. Allergies are the most frequent cause of skin and ear disease in dogs and cats. Other causes include mites, foreign bodies (such as grass seeds), hypothyroidism, autoimmune disorders, and ear tumors. The primary cause of the otitis, such as allergy, may not be readily apparent initially. However, when ear infections recur, or are persistent in spite of treatment, then investigation of the underlying cause is warranted. Investigation may include otoscopic evaluation of the ear, special diets to rule out food allergy, skin tests for allergy, blood tests, or skin biopsies.
Severe, chronic otitis externa results in serious complications for pets, adversely impacting their quality of life. One such complication is antimicrobial resistant bacteria, including Staphylococcus species and Escherichia coli. . Furthermore, after 6 months of ongoing infection, a dog has a significant risk of developing otitis media: infection of the middle ear. Otitis media can eventually lead to nerve damage, and progress to inner ear involvement (otitis interna). This results in paralysis of the facial muscles, loss of balance, and hearing loss. If untreated, the damage can be permanent. Another unfortunate complication of chronic ear infections is swelling and calcification of the ear canal. When extensive, this condition often requires surgical removal of the ear canal in order to eliminate pain and infection.
As a veterinary dermatologist, I evaluate the patient as a whole, and perform diagnostic tests to help identify the primary cause of otitis. I attempt to reverse chronic changes of the ear canal, and recognize patients that would benefit most from surgery. I perform CT scans of the middle ear to identify infection and tumors in the middle ear. I use video otoscopy to get a magnified image of ear structures, and to flush infection and exudates from the ear canal and middle ear. Treating dermatologic patients is often a team effort and requires at-home treatments, so I aim to educate my clients well, and offer support, tips, and guidance as needed. Most importantly, I aim to keep my patients as comfortable and healthy as possible.
I simply cannot stress enough that otitis externa is a painful disease, and early recognition and treatment is essential. Examine periodically the ears of your animals at home. Gently touch and lift the ear flaps and reward your pets with treats and verbal praise. This exercise will help you identify any abnormalities and facilitate positive experiences when medicating the ears topically at home. Please do not attempt to groom or treat your pet’s ears without the guidance of a veterinarian.
Any inflammation, swelling, or discharge of the ears should be investigated by a veterinarian. Be sure to let your veterinarian know if you are unable to administer treatment, if your pet is getting worse, or if the infections return shortly after stopping treatment. Although the complications of ear disease are many, permanent damage may be prevented with early intervention, recognition of the underlying cause, and consistent follow-up.
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Dr. Scott Rizzo is board certified specialist in small animal internal medicine and the medical director for Louisville Veterinary Specialty & Emergency Services (LVSES), Louisville’s largest 24-hr emergency and specialty referral center. For more information on specialty veterinary medicine please visit the LVSES website at www.lvses.com