Clinical observations during adjunctive Cannabis treatment and subsequent oclacitinib dose reduction in dogs with atopic dermatitis

Canine atopic dermatitis is a multifactorial chronic skin disease that is difficult to control and requires lifelong and multimodal therapy. Cannabis has regained medical relevance in several fields, particularly in dermatology, as the endocannabinoid system is uniquely expressed in skin tissues and cells. Modulation through cannabinoids aims to restore skin homeostasis by reducing oxidative stress, inflammation, and consequently the clinical signs exhibited by animals with dermatopathies. This study aimed to evaluate Cannabis oil as a therapeutic option for dogs with atopic dermatitis, for both managing recurrent clinical signs and for enabling oclacitinib dose reduction. Sixteen dogs with atopic dermatitis previously treated with oclacitinib without satisfactory improvement were selected. All dogs underwent a fixed-sequence repeated-measures protocol consisting of four standardized evaluation stages: T0 (oclacitinib alone), T30 (placebo + oclacitinib), T60 (Cannabis oil + oclacitinib), and T90 (Cannabis oil + oclacitinib at 50% reduced dose). Dermatological assessments were performed at each stage to monitor clinical progression and response, including CADESI-4, performed by a veterinary dermatologist, and pruritus scoring, reported by the owners; both were blinded to whether the animal was receiving placebo (mineral oil) or Cannabis oil. Of the 16 enrolled dogs, fourteen completed all study stages through T90. No statistically significant difference was observed for CADESI-4. Likewise, no significant difference in pruritus was observed between T30 (placebo) and T60 (Cannabis oil); however, a significant reduction in pruritus was found between T0 x T60 (p = 0.0010), and T0 x T90 (p = 0.0025). Mild, transient, and self-limiting adverse events, as reported by the owners, were observed during both the placebo and Cannabis oil treatment periods. It is concluded that adjunctive Cannabis oil contributed to improved pruritus control in dogs with atopic dermatitis. In addition, maintenance of pruritus scores was observed following a predefined 50% reduction in oclacitinib dosage, supporting further investigation of Cannabis oil as part of a multimodal therapeutic strategy for canine atopic dermatitis.