Aspectos morfológicos e clínicos da pele de cães com dermatite atópica

Abstract

Canine atopic dermatitis (CAD) is an inflammatory, hereditary skin disease, typically pruriginous and predominantly T cell-induced, involving an interaction between environmental, genetic, immunological factors, and cutaneous microbiome dysbiosis. CAD is one of the most frequent dermatopathies in small animal clinical practice and represents a chronic problem that compromises the quality of life of the affected dogs and their owners. Considering the complexity of CAD and the importance of understanding its structural skin alterations, this study aimed to analyze the morphological and clinical characteristics of the skin of atopic dogs, with an emphasis on the evaluation of collagen fibers. For this purpose, a systematic review of the literature, a histological analysis of the skin of atopic dogs, and a study on the welfare of dogs and their owners were conducted. The studies were approved by the Ethics Committee for the Use of Animals of the State University of Ceará (UECE) and by the Research Ethics Committees involving Human Beings of the Federal University of Ceará and UECE. The systematic review, conducted according to PRISMA 2020 guidelines across four databases, included 14 studies, which revealed heterogeneous findings, divergences regarding increases or decreases of different collagen types, and qualitative analyses that pointed to fibrillar disorganization and impaired transition from immature (type III) to mature collagen (type I). The experimental study was carried out with dogs treated at the Dermatology Service of the Sylvio Barbosa Cardoso Veterinary Hospital and with dogs from the Zoonosis Surveillance Unit, distributed into three groups. In the CAD group, a reduction in dermal collagen fiber density and disorganization were observed, associated with the presence of mild to moderate infiltrate and predominance of immature collagen. In the group of Leishmania spp. seropositive dogs, collagen fibers remained preserved, with inflammatory infiltrate ranging from mild to severe and a predominance of mature collagen. The control group also presented preserved fibers, with an absence of inflammatory infiltrate and greater homogeneity between collagen types. The findings allow us to conclude that the mechanisms involved in CAD expressively compromise the extracellular matrix. Collectively, the results contribute to broadening the understanding of the structural alterations of the extracellular matrix in canine atopic dermatitis and may aid in the development of future therapeutic strategies, aiming to improve the welfare of the animals and their owners.