Effect of ear cleaning on treatment outcome for canine otitis externa.

Background: Ear cleaning is often recommended for management of canine otitis externa (OE). Few in vivo studies evaluate how ear cleaning affects treatment outcome.

Hypothesis/objectives: To determine the effect of ear cleaning on canine OE by comparing treatment outcome in cleaned versus noncleaned ears.

Animals: Twenty-three client-owned dogs with ceruminous or purulent OE.

Materials and methods: Forty ears were randomised to one of two groups: 20 ears were wiped with dry or saline-moistened gauze (grp1), and 20 external ear canals received manual cleaning (grp2) with a commercial product. One millilitre of a commercial otic suspension containing hydrocortisone aceponate, miconazole nitrate and gentamicin sulfate was applied to affected ears every 24 h for five days. Cytological scores, modified otitis index score (OTIS3), pruritus Visual Analog Scale (PVAS), modified PVAS and client questionnaire were compared on Day (D)0 and D7.

Results: There were no statistical differences between cytological scores, modified OTIS3, PVAS, modified PVAS or client assessments between groups at D7. Both groups had significant reduction in all treatment parameters from D0 to D7 with the exception of cytological rod scores that were only significantly decreased in cleaned ears. There was a significant difference in OTIS3 before and after cleaning on D0.

Conclusions and clinical relevance: Both groups achieved successful outcome regardless of cleaning. Ear cleaning may be more important when rod-shaped bacteria are present.