My 13 year old bay horse with black muzzle who is totally healthy has this year developed some patchy areas of pink skin that is almost white around his muzzle. He looks like an appaloosa with the mottling. It’s like he has vitiligo, but I don’t understand how or why.
Relevant history: switched his feed from Hallway Equibility to Excel Carbolyte approximately 5 months prior to this issue. By and large this was not a dynamic shift in feed. My vet was out and noticed it as well and suggested it could be due to a feed change. However, I dismissed it because I had recently cleaned the horse’s grazing muzzle with a diluted bleach solution and attributed it to some irritation–I’ve since soaked the muzzle in water to remove any irritants. However, the mottling seems to be developing in the middle of his nose. The horse is also presently turned out in field with low quality pasture consisting largely of weeds and who knows what. Horse is generally a sensitive creature and is prone to hives after it rains.
Is this possibly related to a feed change? Allergy/reaction to the grazing the muzzle?
