Quiz: Otitis Management in Dogs

According to case files of more than 550,000 pets insured by a major pet insurance carrier, ear infection was the second most common claim filed in 2015.¹

Otitis externa can be discovered during an examination of an animal presented for routine care or may be discovered when presented for a nondermatologic problem.² Common presenting signs include head shaking, otic discharge, otic pruritus, odor from the ear, rubbing of affected ears, and crying out when an affected ear is touched. Of note, as based on clinical observation, otitis externa typically is present, but affected dogs may not exhibit clinical signs or their owners may fail to appreciate the early clinical signs of otitis.<sup2 sup> Performing an otoscopic examination on all nonemergent patients is, therefore, advisable, especially in patients with a history of otitis externa or allergic skin disease, as 80% or more of dogs with food or environmentally triggered atopic dermatitis (AD) have otitis externa.^3,4 If the patient’s ears are painful, sedation may be necessary prior to otoscopic examination.

Diagnosis of otitis externa is only part of the puzzle, however; the second puzzle piece involves identifying the primary cause. Although the primary differential typically is AD, other differentials can involve^5-9:

• Parasitic infection (eg, Demodex spp, Otodectes spp, Sarcoptes spp)

• Foreign body

• Allergic or irritant contact dermatitis

• Autoimmune or immune-mediated disease (eg, pemphigus complex, vasculitis [note that these diseases involve the pinna more commonly than the ear canals])

• Juvenile cellulitis

• Neoplasia (eg, adenoma, adenocarcinoma)

Long-term management relies on identifying and treating (or controlling) the primary cause, addressing secondary microbial overgrowth (eg, bacteria, Malassezia spp) and treating the associated inflammation. Treatment for otitis therefore will include appropriate antimicrobial agent(s) and steroids (topical, with or without systemic treatment, depending on severity of otitis), and providing analgesics for pain relief.^10,11

Although a commonly taught premise involves ear cleaning as essential in controlling and preventing otitis externa, clinical data² do not necessarily support this and, to the author’s knowledge, neither do clinical studies. Of note, research has shown that adding twice-weekly topical steroidal therapy to once weekly ear cleaning can more effectively prevent otitis externa, as compared with ear cleaning alone.¹² This would suggest that controlling inflammation with a topical steroid is more effective than ear cleaning in preventing episodes of otitis externa.