My horse has white spots on her nose that are increasing more and more. I bought her in October and she didn’t have them then. Do you know what it could be ?
It looks like your mare may be developing vitiligo, a loss of pigment. This would be harmless. However such white spots can also appear with a fungal infection, so I suggest you have a veterinarian examine those spots. Fungal infections can be contagious to people and other horses and will need to be treated with an antifungal medication, Your vet may want to take a brush sample of the spots and culture it in order to facilitate a diagnosis.