Single Cold Atmospheric Plasma Therapy May Improve the Treatment Outcome of Canine Otitis Externa With Secondary...

Otitis externa (OE) with secondary bacterial or yeast infection is a common problem in small animal practice. Cold physical plasma (CPP) has been reported to have antimicrobial activity in vitro.

This randomised, blinded, prospective study assessed the influence of additional CPP treatment on the recovery of canine OE with secondary infection.

Twenty-one dogs with bilateral clinical OE and cytological evidence of infection were included.

An ear flush was performed with saline solution in all dogs. Additionally, one ear of each dog, chosen in a prospective randomised fashion, was treated with CPP for 30 s. Afterwards, both ears were treated with a depot ear medication containing betamethasone, terbinafine and florfenicol. Seven days later, the depot medication was administered again as recommended by the manufacturer. On Day (D) 0, D7 and D21, a clinical otic score and a validated semiquantitative cytological score were compared with a Friedman test and Dunn's multiple comparison test.

Ears treated additionally with CPP showed lower otic scores after 21 days compared to nontreated ears, although this difference was not significant (p = 0.08). Cytological scores improved over 21 days with cocci in CPP-treated (p = 0.003) and nontreated ears (p = 0.02). With yeast, there was significant improvement in CPP-treated (p = 0.0002) ears in contrast to nontreated ears. With rods, the improvement was not statistically significant in either group.

CPP treatment seems to be a promising option as an additional treatment after ear flushing.