Is 28 days of doxycycline still justified for canine Lyme arthropathy? A call for a randomized controlled trial

Canine Lyme borreliosis is commonly treated with a 28-day course of doxycycline, a regimen based on historical precedent rather than evidence. Most dogs exposed to Borrelia burgdorferi remain clinically normal despite seroconversion; of those that do develop clinical Lyme disease, the most common presentation is acute or recurrent shifting-leg lameness consistent with Lyme arthropathy. This Viewpoint proposes there is clinical equipoise to evaluate shorter durations of 10 days of doxycycline in dogs with uncomplicated Lyme arthropathy and outlines a prospective parallel-group randomized controlled trial to reassess treatment duration. Determining whether a shorter treatment course is clinically effective also has important implications for antimicrobial stewardship by minimizing unnecessary antimicrobial exposure and selection pressures for antimicrobial resistance.