Chronic otitis in dogs: The clinical consult youve been waiting for

March 14, 2019

The agonizing wait is over. Here, find advice and best practices from veterinary dermatologists around the country for diagnosing and treating otitis.

The wait is over. Go tackle those otitis cases. (James/stock.adobe.com)

 

Chronic otitis plagues dogs across the United States-this is nothing new-but good strategies do exist for both veterinary professionals and pet owners to combat the waiting game that is chronic otitis in dogs. We asked veterinary dermatologists from coast to coast to give us their best diagnostic and treatment advice.

Can you hear me now?

Craig Griffin, DVM, DACVD, of the Animal Dermatology Clinic in San Diego, California, says the first thing he does when faced with a dog with chronic otitis is establish whether the dog can hear. If hearing loss seems permanent and irreversible, Dr. Griffin says, then total ear canal ablation and bulla osteotomy become better treatment options. “Hearing loss is the main side effect of these procedures, so if hearing loss were not an issue, I would spend less time and expense trying medical therapy,” he says. “In addition, hearing needs to be assessed before ear flushing and administering topical medications when otitis media is likely.”

Dr. Griffin also notes that many owners of dogs with fairly apparent hearing loss or deafness are unaware of the issue. “Ask the owner about the pet's response to doors, cars pulling up, and being called when outside and its ability to localize the sound, as well as whether the pet sleeps soundly and anything else that will help determine whether marked hearing loss has occurred,” he says.

When assessing hearing in the examination room, make sounds when the dog is not paying attention to you. It's important to not only see the dog respond to the sound-but also to determine whether it almost immediately localizes where the sound comes from.

Culture and sensitivity: to test or not to test?

Dermatologist Wayne Rosenkrantz, DVM, DACVD, from Animal Dermatology Clinic in Tustin, California, doesn't conduct culture and sensitivity testing in every case of otitis externa. “I start with my otoscopic and cytologic examinations and my review of the history of medications previously used to base my decision on whether culture and sensitivity testing is indicated,” Dr. Rosenkrantz says.

Culture and sensitivity testing does not always isolate the entire bacterial population or yield accurate sensitivity testing depending on the site or level in the ear from where the sample was taken, he notes. “When I do take samples, I like to put a small amount of sterile saline solution in the ear, massage the canal, aspirate a small amount of the fluid out, and then use this fluid to do my culture and sensitivity testing.”

The compliance conundrum

After explaining how to clean a dog's ears, James Noxon, DVM, DACVIM (Small Animal), always asks veterinary clients whether they think they can do it at home. Then comes the critical question for those who say yes: “While you're watching their eyes, ask, ‘Will you?' Those are different things,” Dr. Noxon says. “If they won't, I'm not going to be judgmental, but I need to find something else to do.”

Dr. Noxon doesn't worry if the question seems rude. "My reputation is going to be based on whether they do what I asked them to do,” he says. “If it fails, who do you think they blame?"

Avoid otoscope ouches

Forcing the otoscope down the ear canal may result in a good view, but it hurts and leaves a red, raw area in the canal. This makes the animal sensitive and renders everything that's done afterwards more difficult, says Michael Nappier, DVM, DABVP, assistant professor of community practice in the Department of Small Animal Clinical Sciences at the Virginia-Maryland College of Veterinary Medicine in Blacksburg, Virginia. “Instead of ram-rodding the otoscope,” he advises, “extend the ear canal with your hand and adjust the canal to the cone, not the other way around.”

The role of corticosteroids

Stephen D. White, DVM, DACVD, professor of medicine and epidemiology at the University of California, Davis School of Veterinary Medicine, says the most common cause of otitis in dogs and cats is an underlying allergy. “It's usually atopic dermatitis or sometimes it's food allergy,” he explains. The next most common cause is a severe and difficult-to-clear bacterial infection, such as Pseudomonas.

What veterinarians sometimes don't realize is that even though this is a severe bacterial infection, it's very important to put those dogs on corticosteroids. “We want to reduce inflammation, and steroids will make the dog far more comfortable,” he says. If there's swelling of the ear canal, which is common, steroids will reduce that inflammation so the veterinarian has a less painful dog to examine and can do a decent otoscopic exam.

Choosing a topical treatment

In most cases of infectious otitis externa, topical therapy alone is enough, says Lynette Cole, DVM, MS, DACVD, associate professor and section head of dermatology and otology at The Ohio State University College of Veterinary Medicine. When choosing a topical product, Dr. Cole advises considering the chronicity of the condition, the results of your otic examination, and your otic cytology results. The results of cytologic examination of otic exudate are the basis for your selection of the active ingredient. Keep in mind that ointment- or suspension-based otic preparations may not be as effective as those that are solution- or emulsion-based if the ears are stenotic or hyperplastic, as may be the case in patients with chronic otitis externa, but they can be used if the ears aren't stenotic or hyperplastic or in patients with acute otitis externa.

Choose first-line topical otic medications for cases of acute or occasional otitis externa, reserving second-line otic medications, such as those containing fluoroquinolones, for cases of bacterial otitis due to Pseudomonas species or chronic infections that haven't responded to first-line topical otic antimicrobial products.

Otitis: a team effort

When it comes to an otitis diagnosis, Darin Dell, DVM, DACVD, from the Animal Dermatology Clinic in Indianapolis, Indiana, recommends involving the entire staff. “Receptionists start the process by observing the dog in the waiting area,” Dr. Dell says. “Then, technicians note behaviors when moving the patient to an exam room, and the veterinarian must watch with a keen eye to pick up on subtle movements and actions in the exam room.” Any clinical signs noted, such as the patient rubbing its head against a chair in the waiting room, give the veterinarian clues for asking the client more specific diagnostic questions.