Management of otitis externa with an led-illuminated gel: a randomized controlled clinical trial in dogs

Background: Canine otitis externa is a painful condition which can be challenging to treat due to difficulties in the administration of otic medication. This can be due to lack of owner compliance in the application of ear drops or due to the resentment that some dogs demonstrate when attempts are made to administer topical medication into a sensitive ear canal. The aim of the study was to assess the efficacy of a topical LED-illuminated gel (LIG) in canine otitis externa in comparison to standard of care therapy. Dogs with spontaneous otitis externa were randomly allocated in three groups: groups QW received LIG once weekly; BW received LIG twice weekly; group C received enrofloxacin and silver sulfadiazine twice daily. LIG consists of a topical application of a gel containing chromophores that, when illuminated by a LED lamp, re-emit fluorescent light which can stimulate physiological responses, promoting healing and controlling bacteria. The evaluation protocol (T0 to T5) considered clinical assessment (OTIS-3-index-scoring-system; pruritus-severity-scale; pain-severity-score; aural temperature), cytological scoring system, quali-quantitative bacteriologic assessment. Results: All groups (QW, n = 21; BW, n = 23; C, n = 20) showed improvement during the study (QW: P < 0.02 for cytological and pain scores, P < 0.003 for bacteriologic assessment, P < 10^−4 for pruritus, total OTIS-3 and temperature assessments; BW: P < 10^−4 for all clinical, cytological and bacteriologic assessments; C: P < 0.02 for all clinical and cytological assessments, P < 10^−4 for bacteriologic assessment). The highest clinical score reduction occurred in Group BW (P < 0.014 in T3; P < 0.001 in T4 and P < 10^−4 in T5). BW reached the clinically relevant effect level at T3 (− 3.26 ± 1.21 levels), QW reached it at T4 (− 3.24 ± 0.99), C did not reach it. No differences between groups were seen in the reduction of CFU/mL (T0-T5). Conclusions: All treatment groups showed a positive clinical effect. LIG administered twice-a-week was the most favourable protocol of the study. LIG may be considered beneficial in the management of canine otitis externa; it seems to be effective in controlling the clinical condition, including the signs of inflammation and local pain, the bacterial growth, and it may help increasing treatment compliance.