Discoid Lupus Erythematosus in a mixed breed dog

Case report

Abstract

The objective of this work was to report a case of Discoid Lupus Erythematosus (DLE) in a mixed breed dog, 9 years old and weighing 18 kg. Autoimmune cutaneous diseases are rare dermatoses, characterized by the production of autoantibodies that damage mucocutaneous tissue, causing inflammation and tissue damage, with DLE being the second most prevalent in dogs and considered a benign variant of systemic lupus erythematosus. Its etiology is still unknown, but genetic, endocrine and infectious factors, exposure to ultraviolet light and drug reactions are involved. This pathology has already been observed in dogs, cats, horses and humans. The lesional condition consists of depigmentation, eroded-crusted and ulcerative lesions, erythema, alopecia and pruritus, mainly affecting the periocular region, mirror and nasal bridge. Excluding other skin diseases with similar clinical signs and performing a skin biopsy, and subsequent histopathological examination, allow for confirmation of the diagnosis. Therapy for this disease involves the use of sunscreen, immunosuppressive medication and supplementation of fatty acids and vitamins A and E. The patient in this report was initially seen on April 9^th, 2021, in the city of Nova Iguaçu (Rio de Janeiro) presenting itching, eroded crusty lesions, erythema and alopecia in the nasal bridge and periocular region, in addition to edema and depigmentation in the nasal mirror, and the same had already been seen in 2018 by another professional, at a different location, who did not request additional exams. However, they did prescribe topical treatment with Crema 6A® ointment, without a positive outcome. The diagnosis was obtained through histopathology of the skin lesions (nasal and labial), which confirmed the DLE. On July 28^th, 2023, this patient was seen by another professional at a different veterinary clinic, and PCR (Polymerase Chain Reaction) of skin fragments and serology (ELISA + RIFI with total dilution) for leishmaniasis were performed for differential diagnosis, which yielded negative results. The patient underwent different treatment protocols that were not satisfactory, except for the last (current) one, consisting of immunosuppressive drugs: oral Cyclosporine, and Tacrolimus ointment for topical use in lesions, in addition to the use of sunscreen on the face. The patient in the present study demonstrated a good response, as there was remission of the lesions, erythema and pigmentation, in addition to not presenting any adverse drug reactions.