Good article about adrenal disease written by Dr. Jerry Murray, a well-known ferret expert. The article also contains a video showing what a severely adrenal ferret looks like.
Adrenal gland disease is the most common medical problem in pet ferrets. Ferrets with adrenal gland disease frequently experience hair loss as the first sign of a problem. Over time, additional signs of adrenal gland disease develop. Common clinical signs can include itchy skin above the shoulders, an enlarged vulva in females, an enlarged prostate in males and anemia. Other clinical signs include an enlarged spleen, aggressive behavior, sexual behavior, an increase in musky body odor, bacterial infections of the bladder and prostate, damage to the gallbladder, mammary gland cancer and loss of muscle mass. A few of these signs can be serious and even life-threatening, so adrenal gland disease is definitely worse than just cosmetic hair loss.