Allergies are simply an imbalance of the immune system where your horse’s immune system perceives a threat from something harmless that he has come into regular contact with. Instead of eliminating microorganisms, the body suddenly starts attacking its own tissues, resulting in an overreaction to normal, everyday things such as grass, tree pollens, shavings, dust, molds, hay and straw, environmental pollutants, drugs, fly spray, or a new grooming product or shampoo.
