Systemic Lupus Erythematosus in a Filly

A 2-year-old Standardbred filly was diagnosed with systemic lupus erythematosus (SLE), presenting symptoms such as weight loss, bilateral symmetric alopecia, seborrhea, oral ulceration, and lymphadenopathy. Laboratory tests showed hemolytic anemia and a positive antinuclear antibody test. Skin biopsies revealed interface dermatitis with IgG deposition. Despite treatment with glucocorticoids, the filly was euthanized, and necropsy showed membranous glomerulonephritis and fibrous synovitis. The study suggested that SLE should be considered in horses with immune-mediated skin disease, with diagnosis confirmed through multisystemic disease recognition and specific histopathologic findings.