Investigation of Vitiligo and Its Potential Association with Immune-Mediated Ocular Disease in Equines
autoimmune, vitiligo, uveodermatologic syndrome
Vitiligo is an autoimmune disorder affecting horses across multiple breeds. Although immune dysregulation is considered the primary etiological factor, environmental triggers such as stress and physical trauma may contribute to the onset or progression of the disease. Similar to its occurrence in humans and dogs, the condition is characterized by cutaneous depigmentation resulting from melanocyte loss, clinically manifested as white macules and patches. In humans, a related disorder, Vogt–Koyanagi–Harada disease (uveodermatologic syndrome), is associated with cutaneous and ocular manifestations (uveitis, retinal dysfunction, and, in severe cases, vision loss), as well as involvement of other melanocyte-containing tissues such as the meninges, leading to symptoms ranging from mild headache to neurological impairment and partial or complete hearing loss. In dogs with uveodermatologic syndrome, however, neurological signs have not been consistently documented.
The aim of the present investigation was to characterize cutaneous lesions compatible with vitiligo in equines and to determine whether this condition is associated with ophthalmic alterations. For this purpose, comprehensive clinical evaluations, ophthalmological assessments (including fundoscopy and electroretinography), and histopathological analyses (skin and ocular biopsies) were conducted in 539 horses from diverse regions of the State of Rio de Janeiro.*