Symptoms of Cushing's disease in horses include excessive thirst and excessive urination; weight loss; an abnormally shaggy, thick coat that sheds readily; and a change in the horse's body shape. The animal also suffers from mouth ulcers and laminitis, and is more subject to infections. Laminitis is a potentially crippling inflammation of the material inside the horse's hoof, according to PetMD.
Cushing's disease, also called Cushing's syndrome, develops when a tumor grows in the horse's pituitary gland, says PetMD. The tumor causes the gland to stimulate the body into producing cortisol, which is a stress hormone. Most horses who develop Cushing's disease are over 7 years old. Ponies seem to be more susceptible to Cushing's disease than horses are.
A horse needs to be examined by a veterinarian to diagnose Cushing's disease, as its symptoms are similar to the symptoms of other diseases, according to PetMD. There is no one treatment for Cushing's disease in horses, though the horse is given medication to support its health. These medications include pergolide or cyproheptadine or a combination of these two drugs.
Since a horse with Cushing's disease is very susceptible to laminitis, its hooves need to be monitored with care, claims PetMD. The horse's body and stall must be kept clean to ward off infection, and its diet managed to keep it at a healthy weight.