Evaluation of Dual-Near-Infrared-Wavelength Photobiomodulation Therapy for the Treatment of Canine Otitis Externa: A Prospective Multicenter Pilot Study

This is the first prospective multicenter study investigating photobiomodulation (PBM) in canine OE. Inclusion criteria required an Otitis Index Score 3 (OTIS-3; scale 0–3) ≥1 for erythema and discharge and a Budach cytological score ≥1+ (scale 0–4+) for Malassezia spp. and/or bacteria associated with keratinocytes/corneocytes. Twenty-two dogs with OE (38 ears) were enrolled and underwent five PBM sessions. When the discharge score was ≥2, a ceruminolytic ear cleanser was applied before treatment. OTIS-3, Budach cytological scores, and microbiological cultures were evaluated at T0, T2, T4, and T5. Pruritus was assessed using a 10 cm visual analogue scale, and malodour was recorded as present or absent. Early improvement in pruritus and malodour was observed at T2. Median pruritus scores decreased from 5.5 cm (IQR, 4–6) to 2 cm (IQR, 0–4.75), while malodour prevalence declined from 94% to 54%. Cytological evaluation revealed reductions in yeast and keratinocyte scores, whereas microbiological culture results did not significantly change over time. No adverse events were reported. MLS-based PBM was safe and associated with improvement in clinical signs of canine OE.