Efficacy and safety of a hydrocortisone aceponate-containing ear spray solution in dogs with erythemato-ceruminous otitis externa: A randomised, multicentric, single-blinded, controlled trial.

Background: Erythemato-ceruminous otitis externa (ECOE) is frequently seen in dogs affected with an allergic skin disease, with recurrent secondary bacteria and yeast overgrowths (detected on cytological examination).

Objectives: The objective of the study was to compare the efficacy and safety of an ear spray containing only hydrocortisone aceponate glucocorticoid diester (HCA) to a control product (CTRL), an approved otic formulation containing prednisolone-miconazole-polymyxin combination, in dogs with ECOE.

Animals: In total, 97 and 104 dogs with ECOE were respectively randomly assigned to the tested ear treatment product group (HCA) or the commercially available ear treatment control product group (CTRL).

Materials And Methods: Dogs were treated for 7-14 days, as needed. At Day (D)0, D7, D14, D28 and D42, Otitis Index Score-3, hearing test, pruritus and pain visual analogue scales, and cytological scores were graded. The overall response to treatment also was assessed.

Results: All clinical parameters decreased rapidly and in a similar way without any significant difference at any time between treatment groups. A good-to-excellent response to treatment was seen in >90% of dogs of both groups as early as D14. The treatment was considered safe in all dogs.

Conclusions And Clinical Relevance: A 7- to 14-day ear topical application of HCA alone to dogs with ECOE accompanied with bacterial and/or fungal (yeast) overgrowth was safe and led to no statistical difference in improvement of clinical scores relative to the CTRL combination. Based on these results, it may be necessary to reconsider the routine use of antimicrobial drugs such as antibiotics and antifungals as a first-line treatment for ECOE that is likely to have been caused by an allergic reaction.