Efficacy and safety of 0.0584% hydrocortisone aceponate topical spray and systemic oclacitinib combination therapy in dogs with atopic dermatitis: a randomized, double‐blinded, placebo‐controlled trial

<jats:sec><jats:title>Background</jats:title><jats:p>Oclacitinib is an effective systemic therapy for dogs with atopic dermatitis (AD). Few studies have evaluated concurrent topical treatment with oclacitinib in dogs.</jats:p></jats:sec><jats:sec><jats:title>Objectives</jats:title><jats:p>To evaluate the efficacy and safety of combination therapy of oclacitinib and 0.0584% hydrocortisone aceponate (HCA) spray in dogs with AD.</jats:p></jats:sec><jats:sec><jats:title>Animals</jats:title><jats:p>Eighteen dogs with AD.</jats:p></jats:sec><jats:sec><jats:title>Methods and materials</jats:title><jats:p>This study was a randomized, double‐blinded, placebo‐controlled trial. All dogs were treated with oclacitinib (0.4–0.6 mg/kg twice daily for 14 days, then once daily for 14 days) and randomized to receive either HCA spray or placebo spray, applied once daily for seven days then every other day through to Day (D)28. Clinical assessments included the Canine Atopic Dermatitis Extent and Severity Index, 4<jats:sup>th</jats:sup> iteration (CADESI‐4) and the pruritus Visual Analog Scale (PVAS) every seven days, and blood and urine tests every 14 days.</jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p>The mean CADESI‐4 and PVAS scores were significantly reduced on D7 and D14 compared to D0 in both groups (<jats:italic>P</jats:italic> < 0.05). From D14 to D21, CADESI‐4 and PVAS scores were significantly increased in the placebo group (<jats:italic>P</jats:italic> < 0.005), and not in the HCA‐treated group. The mean reduction from baseline of the HCA‐treated group was significantly higher than that of the placebo group for the PVAS and CADESI‐4 on D21 (59.9% versus 27.6%, <jats:italic>P</jats:italic> = 0.0216) and D28 (56.0% versus 30.5%, <jats:italic>P</jats:italic> = 0.0109), respectively. One dog in the HCA‐treated group was withdrawn as a consequence of developing diarrhoea.</jats:p></jats:sec><jats:sec><jats:title>Conclusion</jats:title><jats:p>Topical application of 0.0584% HCA spray may be useful for preventing exacerbation of pruritus and clinical lesions when tapering oclacitinib therapy in dogs with AD.</jats:p></jats:sec>