Question
I’m shopping for an Arabian horse, and one candidate has patches of vitiligo. In searching for information on vitiligo, some advocate increasing vitamin A, B-group vitamins, and biotin to potentially reduce spread, and some think it’s related to a copper deficiency. Is there any actual research on nutritional factors? What are your thoughts?
Answer
Vitiligo refers to an acquired depigmentation of the skin in areas of no known trauma. In addition to vitiligo, the condition is sometimes called pinky syndrome or Arabian fading syndrome, due to its prevalence in that breed. Vitiligo was first mentioned in the veterinary literature in 1931, though it would be decades, not until the 1960s, before it was again reported in a published article.
Vitiligo is an autoimmune disease in which the body attacks the melanin, or pigment-producing, cells of the skin. Humans with autoimmune thyroid disease or type 1 diabetes are more susceptible to the disease. With horses, it is curious how depigmented areas come and go spontaneously, indicating that there may be a stress component involved with the autoimmune condition.
Scientists have not discovered any way to prevent or cure vitiligo. Treatments involving vitamins and herbs, such as folic acid, vitamin C, and vitamin B-12, have reportedly helped some animals. Ginkgo biloba was effective in restoring skin color or stopping progression of vitiligo in a human trial, but research with horses has not been performed.
The few studies conducted in horses with vitiligo have yielded confusing results, as there may have been confounding factors with regard to the development of the disease in two of the studies. For example, one study described curing horses by feeding 9-11 lb (4-5 kg) per day of carrots for one year, but the vitiligo may have been caused by a vitamin A deficiency.* The drug and light therapies used in humans have not been tested in horses and may be cost-prohibitive.
Making sure the horse has a balanced diet with a complete complement of trace minerals (including adequate copper) and vitamins A, D, and all the B vitamins would be a logical starting point if you decide to purchase this horse. You may want to consider adding a hoof and coat supplement that includes biotin, which improves these keratin-based tissues in many horses.
The fortunate thing about vitiligo is that it most likely doesn’t bother the horse. One exception: when it appears around the eyes and muzzle, as it predominantly does in horses, the skin might be more susceptible to sunburn, and measures should be taken to avoid overexposure to the sun.
*Tham, H.L., K.E. Linder, and T. Olivry. 2019. Autoimmune diseases affecting skin melanocytes in dogs, cats and horses: Vitiligo and the uveodermatological syndrome: A comprehensive review. BMC Veterinary Research 15:251.
