Nitric-zinc topical shows promise for equine aural plaques

A new retrospective case series in Equine Veterinary Journal suggests that topical nitric acid and zinc solution may offer veterinarians a practical option for treating equine aural plaques, a papillomavirus-associated condition that can make horses ear-shy and difficult to handle. Reviewing cases from two Swedish equine clinics between 2012 and 2022, investigators treated 20 affected ears in 12 horses with nitric-zinc complex products sold as Oxalic® or Verrutop®. Seventeen ears achieved complete remission after one to five treatments, while the other three improved substantially and discomfort resolved. The authors reported no adverse effects, though the study was small, retrospective, uncontrolled, and based on clinical diagnosis without PCR or histopathology. (publications.slu.se)

Why it matters: Aural plaques can be frustrating to manage because many cases are chronic, linked to equine papillomavirus, and often respond poorly to anecdotal therapies. Standard references note that imiquimod can work, but it commonly triggers marked inflammation and often requires sedation, which limits practicality for some patients and pet parents. Against that backdrop, a treatment approach that appeared effective without reported adverse effects could be meaningful for equine practitioners, especially when plaques are contributing to ear sensitivity, bridling problems, or handling issues. Still, the evidence is early, and clinicians should weigh the lack of controls and confirmatory diagnostics before changing practice broadly. (merckvetmanual.com)

What to watch: The next step is whether prospective, controlled studies confirm efficacy, define recurrence rates, and compare nitric-zinc treatment directly with imiquimod or conservative management. (publications.slu.se)