BackgroundHyperkeratotic erythema multiforme (HKEM) is a clinically distinct dermatosis and poorly characterized syndrome, comprised of hyperkeratotic plaques with variable symmetry and apoptosis similar to “classic” erosive canine EM. Hyperkeratotic EM has a protracted clinical course and, although treatments with glucocorticoids, azathioprine and/or ciclosporin have been tried, rates of remission are low.ObjectivesTo describe successful treatment of HKEM in two dogs using oclacitinib.AnimalsA 7‐year‐old, spayed Havanese dog (Case 1) and a 1‐year‐old, intact cryptorchid Dachshund dog (Case 2).MethodsCase characterization and clinical diagnoses were based on lesion character, surgical biopsy, cytological evaluation, culture, direct immunofluorescence (DIF) and expected responses to treatments.ResultsBoth cases exhibited multifocal, often symmetrical hyperkeratotic plaques with adherent scale. Histological findings revealed prominent epidermal hyperplasia, parakeratotic hyperkeratosis, lymphocytic dermatitis and transepidermal apoptosis with lymphocytic satellitosis. DIF revealed fine, patchy IgG, IgM and IgA basement membrane deposits (Case 2). Both dogs exhibited rapid improvement with oral oclacitinib (0.6–0.9 mg/kg twice daily) with a complete remission of clinical signs observed in 12 and seven weeks in cases 1 and 2, respectively.Conclusion and Clinical ImportanceOclacitinib could be considered as a fast‐acting and effective treatment option for HKEM in dogs.

Background Clinical trials enrolling dogs with atopic dermatitis (AD) use validated instruments that aggregate the extent and severity of selected skin lesions; none of these provides a global assessment of the severity of all lesions. Objectives To validate an Investigator Global Assessment (IGA) instrument to globally evaluate the severity of skin lesions in dogs with AD. Animals Forty dogs with AD. Methods and materials A 2D graphic IGA (2D‐IGA) instrument was created to subjectively score, with a single dot, the overall extent and severity of all canine AD lesions. This tool was tested for its validity (content, construct and criterion), reliability (inter‐ and intraobserver) and sensitivity to change. Results The content of the 2D‐IGA was first validated by a supportive vote by the International Committee of Allergic Diseases of Animals (ICADA) membership. Its construct was verified by positive correlations between the 2D‐IGA scores and those of the Canine Atopic Dermatitis Extent and Severity Index, 4th iteration (CADESI‐04) and the Canine Atopic Dermatitis Lesion Index (CADLI) (Spearman’s rank‐order correlation, P < 0.0001). The positive correlation (P < 0.0001) between an Owner Global Assessment of Disease Severity (OGADS) and the 2D‐IGA indirectly satisfied its criterion. Scores graded by the same investigator hours apart and those between investigators were positively correlated (P < 0.0001), thereby validating this scale's intra‐ and interobserver reliabilities. Finally, the changes in 2D‐IGA values during treatment were correlated positively with scores of an Owner Global Assessment of Treatment Efficacy (OGATE; P < 0.0001), thus showing its sensitivity to change. Conclusions and clinical importance This novel 2D‐IGA is a simple static graphic instrument that could be useful for clinical trials testing the efficacy of interventions for canine AD.