Today I am going to address a problem that many ferret owners encounter and may be to embarrassed to ask about: the naked ferret. If your ferret holds still enough between bouts of flinging your socks out of the drawer, hiding the car keys under the couch, and hopping sideways and hissing, you may have noticed that he or she has been losing hair from the tail, over the shoulders or on the belly. Usually this is a ferret who is otherwise acting and feeling normal. Did your pet just secretly sign up for the National Ferret Nudist Society? As it turns out hair loss in ferrets is not just a matter of modesty, it is the primary clinical sign of a common ferret malady, an adrenal tumor.
The adrenal glands are located near the kidneys and are responsible for making many different hormones that regulate many different body functions. In the case of ferrets the portion of the adrenal glands that is the secondary production zone for estrogens, progesterones, and testosterones, the sex hormones, becomes enlarged. It starts indiscriminately pumping out those hormones, ignoring balance systems that keep them at appropriate levels. High levels of estrogens deactivate hair follicles, thus the nakedness, but they have a more sinister effect on the bone marrow, causing it to lose it’s ability to make new red blood cells and white blood cells. Eventually the anemia resulting from non functioning bone marrow can be fatal. Male ferrets can develop prostate enlargement that can lead to prostate and bladder infections. The sludge in the bladder resulting from an infection can cause urinary obstruction which, as you could imagine, becomes an emergency situation quickly. Female ferrets often develop a swollen vulva that goes from looking like a tiny nub to looking like a Krispy Kreme donut.
Ferrets will often show symptoms of adrenal disease for months or even years without seeming to feel sick at all. Most adrenal tumors start in ferrets between the ages of three and five years and are very slowly progressive, but when they start causing systemic illness the situation is more likely to have moved into a more untreatable zone.
The treatment of choice is surgical removal of the affected adrenal gland. Often this is a fairly straightforward procedure, but sometimes there may be complications that make that impossible. Large adrenal tumors have a tendency to invade into major blood vessels and it is considered poor form for the surgeon to put a fatal hole in a big vein while trying to extricate an obstinate adrenal gland. When the adrenal tumors cannot be approached surgically there are some medical treatments that are also showing promise. One is a monthly injection of Depo Luperon, a human medication that suppresses the excessive production of sex hormones. It has been shown to be effective in the reduction of symptoms, but does not seem to slow the growth of the tumor itself. The shot needs to be repeated every month and it tends to be very expensive. Recently another hormone, melatonin, has been formulated into an implant that seems to have similar effects as the Luperon injections but it only needs to be repeated every three months and is considerably more cost effective. The melatonin implants have also been proposed as possible preventatives for adrenal disease. Melatonin implants are new enough that there is not much long term data out on their effectiveness, but so far the results look promising.
So why does this happen to ferrets? There are several theories, including genetic tendencies in the breeding population, early spays and neuters before ferrets enter the pet market, exposure to unnatural light and dark cycles for ferrets that are indoor pets, and possible dietary connections. None of these theories has been definitively proven to be the cause, and it is most likely a combination of several factors that predispose ferrets to developing adrenal disease.
Now that you know that your ferret is not just an exhibitionist you have a better chance of preventing long term problems and giving your pet many more years to gleefully excavate all the dirt from your houseplants and sweep all the dust bunnies out from under your refrigerator.