Otitis externa is one of the most frequently observed dermatological conditions in veterinary practice. Its multifactorial nature, the tendency to recur, and the potential involvement of bacteria and yeast necessitate a structured diagnostic and therapeutic approach.
In recurrent or chronic cases, the need for repeated topical anti-inflammatory, antifungal, or antibacterial treatments is also a matter of growing concern, particularly within the context of a responsible use of antimicrobials and of the fight against antimicrobial resistance.
It is against this backdrop that a prospective multicentre study, published in 2026 in the open-access journal Animals, assessed the feasibility, safety, and preliminary clinical outcomes of MLS® Laser Therapy in dogs suffering from otitis externa.
According to the authors, this is the first prospective multicentre study dedicated to photobiomodulation delivered via the MLS® system for managing this condition.
A study born from the collaboration between clinical practice and research
Launched in 2023 through a collaboration with the AniCura Istituto Veterinario di Novara, the project involved the AniCura Ospedale Veterinario Portoni Rossi, the “Togo Rosati” Istituto Zooprofilattico Sperimentale of Umbria and Marche, the University of Padua, the Vetsuisse Faculty of the University of Zurich, and ASA.
The research group combined expertise in clinical dermatology, cytology, microbiology, statistical analysis, and medical technology, integrating these disciplines into a single multicentre protocol.
How the study was conducted
The pilot study included 22 privately owned dogs, for a total of 38 ears affected by unilateral or bilateral otitis externa.
Patients were required to exhibit erythema and secretions detectable via the OTIS-3 system, alongside cytological evidence of Malassezia spp. and/or bacteria associated with keratinocytes or corneocytes.
Dogs with parasitic, neoplastic, suppurative, or ulcerative otitis, or suspected tympanic membrane rupture, were excluded, as were those recently treated with ear medications, antibiotics, corticosteroids, NSAIDs, or immunomodulators.
Treatment efficacy was assessed using clinical parameters—including erythema, oedema, secretion, pain, pruritus, and malodour—alongside cytological examinations, quantitative microbiological cultures, and evaluations of safety and tolerability.
Cytology results were interpreted by a third-party veterinarian who was blinded to the clinical data and protocol timeline. Microbiological analyses were also performed by laboratory personnel who were blinded to the study details. This approach minimises the risk of subjective bias in result interpretation.
Five sessions using a dedicated MLS® protocol
Each affected ear underwent five sessions with the MLS® M-VET system, which combines two synchronised near-infrared emissions at 808 nm and 905 nm.
The protocol involved scanning the external projection of the vertical and horizontal ear canal segments, followed by point-by-point application on the pinna. The treatment area and number of points were adjusted according to the patient's size.
The second session took place 24 hours after the first, while subsequent sessions were scheduled at 48–72 hour intervals. The final assessment was performed 24–48 hours after the fifth treatment.
Full application parameters are available in the original publication.
What changed after five sessions?
| RESULTS | ||
|---|---|---|
| Parameter | Baseline value | Final value |
| Erythema | 2 | 1 |
| Oedema | 1 | 0 |
| Secretion | 2 | 1 |
| Pain | 1 | 0 |
| Pruritus, VAS scale | 5,5 cm | 2 cm |
| Foul-smelling ears | 94% | 54% |
At the end of the protocol, a statistically significant improvement was observed in most clinical parameters.
Changes in erythema, oedema, secretion, pain, pruritus, and foul odour reached statistical significance.
A particularly clinically interesting finding concerns the speed of certain responses: a significant reduction in pruritus and of the prevalence of foul odour was already detectable after the first two sessions.
No adverse events, treatment-related pain, irritation, or tolerability issues were observed during the study.
What do the cytology and microbiology results suggest?
Cytological examination revealed a significant reduction in Malassezia yeasts and in keratinocytes/corneocytes. Conversely, quantitative cultures showed no significant changes in the microbial load of the pathogens analysed.
The observed clinical benefits do not, therefore, appear to stem primarily from a direct antimicrobial action. Instead, the authors hypothesise an effect linked to the modulation of inflammation and to the progressive restoration of the ear canal micro-environment.
The reduction in keratinocytes and corneocytes may reflect a normalisation of epithelial turnover, while the decrease in Malassezia observed via cytology could be associated with local conditions that are less favourable to yeast proliferation.
This interpretation aligns with the role of MLS® Laser Therapy in modulating inflammatory processes, pain, oedema, and tissue repair mechanisms.
Where does MLS® Laser Therapy fit into clinical practice?
MLS® Laser Therapy does not replace aetiological diagnosis, cytology, otoscopy, or pharmacological treatments when indicated. It can be considered an adjunct to a multimodal approach, aiming to help control inflammation, oedema, pain, pruritus, secretion, and alterations in the aural micro-environment.
A new milestone in veterinary research
This publication represents a significant step in ASAveterinary’s research journey and highlights the value of collaboration with veterinary referral centres, specialised laboratories, and academic institutions.
The project's value lies not only in the results obtained but also in the research model adopted: a real-world clinical issue, a standardised technological protocol, multidimensional assessments, and a cautious interpretation of the data.
Developing scientifically grounded veterinary therapeutic solutions requires continuity, multidisciplinary expertise, and constant engagement with clinical practice.