Double Blinded, Randomized and Controlled Comparative Study Evaluating the Cleaning Activity of Two Ear Cleaners in Client-Owned Dogs with Spontaneous Otitis Externa

Ear cleaning is a therapeutic component in the management of otitis externa in dogs. The objectives of this study were to evaluate the in vivo efficacy and safety of a new ear cleanser, Sonotix® against EpiOtic® Advanced for the management of canine otitis externa. Eighteen clients owned dogs with a diagnosis of erythemato-ceruminous or purulent otitis externa were prospectively included and randomized to two treatment group: EpiOtic® Advanced and Sonotix®. Cytology and video-otoscopic examination (erythema, amount of cerumen and thickness and surface of ear canal covered by cerumen) of all affected ears were done at D0, both before (T0) and 30 minutes (T0 + 30 min) after ear cleaning. Then an ear medication was applied (Aurizon®, Vetoquinol). Owners were instructed to clean affected ears daily and apply the ear medication 30 minutes later for 5 days (D1-D5). Dogs were seen again at D6 for cytology and video-otoscopic examination. At T0, no significant differences were found between both ear cleansers groups regarding macroscopic and microscopic scorings. At T0 + 30 min and D6 cytological and video-otoscopic scores were significantly decreased (Wilcoxon test; p < 0.01) compared to baseline in both groups. However, the cleaning activity of Sonotix® was statistically superior to Epiotic® as evidenced by the median global scores of video-otoscopic examination at T0 + 30 min (Mann Whitney Test, p < 0.01). Effective ear cleaning is an essential part of any treatment scheme because it favours the contact between the ointment and the lining ear epidermis and speeds resolution by the removal of cerumen, microbial organisms and cellular debris. In our study, the important reductions in yeast, cocci, and rod-shaped organism counts were demonstrated in smears at T0 + 30 min and D6 in both groups. Video-otoscopic examination performed 30 minutes after ear cleaning suggests that Sonotix® seems to be more effective in removing cerumen than EpiOtic® Advanced.