Otitis externa (OE), an inflammation of the external ear canal, is common in both humans and companion animals and often requires prolonged antimicrobial therapy. Ozone has gained attention for its antimicrobial, antiviral, and antioxidant properties in dermatologic disorders, although its optimal dose and route of administration remain unclear. This study aimed to evaluate the efficacy of topical ozone therapy for managing OE compared with conventional antimicrobial treatments. Twenty-seven client-owned dogs with OE were enrolled in an open-label, prospective, controlled clinical trial and assigned to three groups: ozone (Group I), ciprofloxacin drops (Group II), and a veterinary otic solution with florfenicol, terbinafine, and mometasone furoate (Group III). Clinical assessments (OTIS-3, otoscopy, pain, pruritus, cytology) were performed on days 0, 7, 14, and 21, with bacteriological evaluations on days 0 and 21. Based on OTIS-3, treatment success rates were 100 % in Group I, 33.33 % in Group II, and 66.66 % in Group III. Significant improvements in OTIS-3, otoscopy, pain, and pruritus scores were observed in Group I compared to Group II (p < 0.05). Cytological improvement was significant in Groups I (p < 0.001) and III (p = 0.003). Microbiological analysis confirmed the complete absence of bacterial growth in Group I, effectively eliminating Staphylococcus pseudointermedius, Proteus mirabilis, Bacillus spp., Citrobacter braakii, Coagulase-Negative Staphylococci, Escherichia coli, Dermacoccus nishiomiyaensis, and multidrug-resistant Acinetobacter baumannii. These findings highlight the potential of topical ozone therapy as a safe and effective option for the management of otitis externa, with important implications for reducing antimicrobial use and mitigating antimicrobial resistance.
Keywords: Bacteriology; Dermatology; Dog; Otitis externa; Ozone.
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