Hypochlorous Acid Ear Flush in Dogs With Chronic Otitis Externa

Frane Banovic, DVM, PhD, DECVD, University of Georgia

ArticleLast Updated August 20233 min read
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In the Literature 

Mueller RS, Baumann KN, Boehm T, Dörfelt S, Kasper B, Udraite-Vovk L. Evaluation of hypochlorous acid as an ear flush in dogs with chronic otitis externa. Vet Dermatol. 2023;34(2):134-141. doi:10.1111/vde.13142

The Research …

Chronic or recurrent otitis externa (OE) in dogs can lead to diminished quality of life and be challenging to treat. Hypochlorous acid is a major oxidant produced by neutrophils and a potent in vitro microbicidal agent against common pathogens (eg, Staphylococcus pseudintermedius, Malassezia pachydermatis) isolated in dogs with OE. Although the antimicrobial activities of hypochlorous acid have been evaluated in several in vitro studies,1,2 hypochlorous acid has not been evaluated in-depth as an antiseptic ear flush.

This prospective study* evaluated the safety and efficacy of hypochlorous acid as an ear-flushing and antimicrobial agent, as well as an adjunctive ear cleaner, in 20 dogs with chronic bilateral OE. Most dogs had recurrent OE due to allergic skin disease (eg, atopic dermatitis); the underlying condition was unclear in 3 dogs. Each dog was placed under anesthesia and had both ears flushed using a video otoscope; one ear was flushed with a 0.015% hypochlorous acid solution and the other ear was flushed with saline (control). Clinical scores for ears were determined prior to flushing; cytology samples and a hearing test were conducted before and after flushing; and cultures were obtained immediately following flushing.

For 2 weeks after flushing, the ear previously flushed with hypochlorous acid solution was cleaned twice daily with the same solution, and the control ear was cleaned using a commercial ear cleanser. In addition, all dogs received an otic medication containing miconazole, polymyxin B, and prednisolone in both ears once every 24 hours.

Ears were re-evaluated following 2 weeks of therapy. Five ears that received hypochlorous acid intervention and one ear that received saline flush intervention were negative on aerobic bacterial culture. Clinical scores for both interventions improved significantly after 2 weeks of treatment, and there was no significant difference between treatment ears and control ears in clinical, cytologic, or hearing scores at any time point. No adverse effects were observed during the study.

The authors concluded 0.015% hypochlorous acid solution can be safely used as a suitable cleaning solution in dogs with OE. 

… The Takeaways 

Key pearls to put into practice:

  • The most common underlying cause of chronic OE in dogs in this study was allergic skin disease (eg, atopic dermatitis). 

  • Flushing ears of anesthetized dogs with hypochlorous acid and using this agent as an ear cleaner in combination with commercial ear medications for chronic OE appears effective and safe. 

  • In addition to ear flushing and medications, underlying diseases (eg, allergies) causing chronic and recurrent OE in dogs should be appropriately managed.  

*This research was funded by Ecuphar GmbH.