Otitis externa in canines can stem from myriad causes, including allergies, parasites and foreign bodies. Thus, any dog can develop an ear infection. However, certain breeds are at greater risk than others. In these instances, owner education and preventive measures can be critically important. Carlo Vitale, DVM, Dipl. ACVD, a veterinarian at San Francisco Veterinary Specialists in California, says allergies—primarily atopic dermatitis and, to a lesser extent, food allergies—represent the greatest otitis risk factor in dogs. The breeds he sees as most prone to ear infections are those with a higher incidence of atopic dermatitis, including most terriers, Labradors, golden retrievers, Dalmatians, Shar Peis, chow chows, Shiba Inus and pit bulls. Marcia Schwassmann, DVM, Dipl. ACVD, a veterinarian at Veterinary Dermatology Center in Maitland, Fla., notes that the breeds in which veterinarians most commonly see allergy-related ear infections will differ by region, as popular breeds and types of allergens are not consistent across the country. Every veterinarian might have a unique list of the breeds that seem most prone to allergies—and thus, ear infections. Nicola Williamson, DVM, Dipl. ACVD, owner and practitioner at Veterinary Dermatology of Richmond in Virginia, also says allergies represent the greatest otitis risk factor she sees in her practice. She adds that predisposing causes of ear infections include conformational and anatomical factors, excessive moisture (such as from bathing or swimming), obstructive ear disease (such as tumors or polyps), and iatrogenic factors (such as traumatic hair removal, aggressive use of a cotton-tipped applicator, or inappropriate medications or cleaners). Dr. Schwassmann notes, however, that predisposing factors don’t necessarily mean a dog will get ear infections. “A lot of people ask me whether their dogs’ ear infections occur because the pet swims,” she says. “But there are plenty of dogs who swim but don’t get recurrent ear infections.” In other words, it is important not to conflate primary causes and aggravating factors. A good example is cocker spaniels. These dogs are notorious for their predisposition to ear infections, and some people may be inclined to blame this on their pendulous ears. However, Alice Jeromin, RPh, DVM, Dipl. ACVD, owner of Veterinary Allergy & Dermatology Inc. in Richfield, Ohio, notes that some of the worst otitis she’s seen has been in shepherds—breeds that do not have pendulous ears. As noted above, the principal issue for many dogs is underlying allergy. Swimming or other predisposing factors only make it more likely that an ear infection will develop in these susceptible animals. Because of the importance of both causes and risk factors to the management of canine otitis externa, Schwassmann says veterinarians should focus on early education of owners who have breeds that are predisposed to ear infections. “Preventive care directed toward predisposing factors is something we like to start when the pet is young,” she says. “We tell the owners, ‘It tends to be a problem in these breeds.’” That said, prevention often cannot occur until there’s been proper treatment. “To encourage compliance, it’s important for owners to see success with treatment and to be encouraged then to perform the mentioned preventive methods,” Vitale says. He suggests that proper otitis treatment depends on both the type of infection and the underlying cause. Different medications are required to treat bacterial and yeast organisms. As a consequence, it is extremely important to perform otic cytology on every presentation of these patients. Dogs with itchy and painful infections might also benefit from low-dosage corticosteroids, Vitale says. “In cases of bacterial otitis, a culture might help to determine the appropriate antibiotic to use—generally topical,” says Vitale, adding that severe or resistant infections might also call for an oral antibiotic. Baytril Otic (enrofloxacin/silver sulfadiazine) Emulsion is a broad-spectrum antibacterial medication useful in managing canine otitis externa aggravated with bacterial and fungal infections. Enrofloxacin and silver sulfadiazine both act against a variety of otic bacterial pathogens. Additionally, silver sulfadiazine is an effective antimycotic. “Baytril Otic has proved useful for cases of severe Pseudomonal otitis or for some cases of resistant Staphylococcus—which we are seeing more and more of these days,” Vitale says. And as a water-based emulsion, Baytril Otic is designed for deep penetration into ear canals. Beyond treatment, veterinarians must actively encourage owners to prevent recurrent infections, particularly among high-risk breeds. Dr. Williamson notes that educating owners and giving them positive reinforcement is very important. “Once owners understand why the infections are occurring, they are much more likely to comply with recommendations of cleaning, medicating and treating any underlying cause of the otitis,” she says. Schwassmann says that veterinarians must also teach owners how to perform routine ear cleanings and evaluate their dogs’ ears to ensure they both look and smell healthy. While the No. 1 preventive measure is to treat underlying causes such as allergies, the doctors stress that maintenance cleaning with a mild antibacterial and antifungal cleaner can be beneficial. Vitale adds that dogs that swim or have pendulous ears may benefit from more frequent ear cleansing, perhaps as frequently as every other day. “Increased [washing] frequency can definitely increase success as preventive therapy.” Dr. Jeromin recommends that owners set specific days of the week to perform ear cleaning. Williamson and Jeromin both stress that grooming can also aid in maintenance. “Dogs with pendulous ears that develop infection often benefit from keeping the concave surface of the pinnae clipped so that there is better air circulation and debris does not get matted, which can further complicate the problem,” says Williamson. Similarly, Jeromin says, “Dogs that have excessive hair in the ear canals and have ear problems may benefit from having the ears plucked,” she says. However, she adds, “If the dog has excessive hair and no infections, I don't recommend plucking the hair.” Williamson notes it is important to recheck otitis patients before the ear medication is stopped. “The ear needs to be examined with an otoscope, and cytology needs to be performed,” she says. “Twenty-five percent of recurrent ear infections recur because they were never cleared in the first place.” This Education Series article was underwritten by Bayer Animal Health of Shawnee Mission, Kan.
