CUSHING'S DISEASE -- Cushing's disease is the result of the overproduction of cortisone, an natural steroid hormone, by the adrenal glands. It is rare in dogs under five years old. In about 80 percent of the dogs the disease is caused by a lesion in the pituitary gland at the base of the brain that over stimulates the adrenals, while in about 20 percent of cases one of the adrenal glands itself will have a tumor that excretes cortisol independent of what's happening in the body. About half of those tumors are malignant and spread, and about half of them are benign and generally tend to stay small.

The symptoms of Cushing's disease can also appear if a dog is taking steroids for a medical condition and ends up with too much in his system. Steroids are found in a lot of creams, eye ointments and ear ointments, and if you get overzealous with their administration, that can cause these signs as well. When you stop using the products, these symptoms will go away.  The typical signs of Cushing's disease are increased thirst and urination, panting, hair loss (usually on the trunk) and weakness.