Rapid response of hyperkeratotic erythema multiforme to oclacitinib in two dogs

Abstract

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.

Beneficial effect of oclacitinib in a case of feline pemphigus foliaceus

“…5 In dogs, the JAK inhibitor oclacitinib has been effective in controlling other immune-mediated diseases, including subepidermal blistering dermatoses, ischaemic dermatopathy and hyperkeratotic erythema multiforme. [6][7][8] The off-label use of oclacitinib in this case was based on these prior reports in other species, and the dose selected was based on a pharmacokinetic study in cats. 9 Oclacitinib's mechanism of action for successful treatment of this case is unknown.…”

“…Janus kinase (JAK) inhibitors interfere with the intracellular signalling pathway of JAK‐STAT (Signal Transducer and Activator of Transcription) exerting a wide range of anti‐inflammatory and immunosuppressive effects. This class of drugs now is being used in alternative therapies for some neoplastic and immune‐mediated diseases in human beings and dogs 5–8 . This report describes the successful treatment of a cat with PF, using the JAK inhibitor oclacitinib (Apoquel, Zoetis; Madrid, Spain), which is registered for use in dogs with atopic dermatitis.…”

“…This class of drugs now is being used in alternative therapies for some neoplastic and immune-mediated diseases in human beings and dogs. [5][6][7][8] This report describes the successful treatment of a cat with PF, using the JAK inhibitor oclacitinib (Apoquel, Zoetis; Madrid, Spain), which is registered for use in dogs with atopic dermatitis.…”

Extra‐auricular lesions of proliferative and necrotizing otitis externa in three kittens

“…Interestingly, EA lesions were clinically and histopathologically similar to those found in the hyperkeratotic erythema multiforme (HKEM) of dogs in which erosive and hyperkeratotic lesions are linked to an analogous cytotoxic attack on keratinocytes by T cells. 6 Unlike PNOE, which affects mostly kittens and has a good prognosis, HKEM affects dogs in their mid-to late adulthood and is considered refractory to treatment with low remission rates reported with glucocorticoids and/or ciclosporin. 6 The prognosis of PNOE is generally good.…”

“…6 Unlike PNOE, which affects mostly kittens and has a good prognosis, HKEM affects dogs in their mid-to late adulthood and is considered refractory to treatment with low remission rates reported with glucocorticoids and/or ciclosporin. 6 The prognosis of PNOE is generally good. 1 In these three reports, EA lesions behaved in a similar way to PNOE.…”