Megan, it is not common for people who are allergic to cats to be be
allergic to ferrets.  What people are allergic to in cats is the dander
they produce by grooming.  Ferrets, like dogs, produce no dander.  A
person is less likely to be allergic to ferrets than to dander producing
animals like cats and birds.
 
I am deathly allergic to cats; I am not allergic to ferrets.  I had one
incident though, where I thought I was allergic to ferrets.  A ferret
came into the shelter; the family who brought him in said they had just
put flea powder on him (bad).  I was apparently allergic to the flea
powder because once we bathed him, I was fine.
 
The Ferret FAQ (http://www.ferretcentral.org/faq/part1.html) has a nice
little article on ferret allergies.
 
Melanee Ellis
"The Ferret Lady"
Juneau, Alaska
 
P.S.  I've been following the tattoo thread -- I just got a tattoo of a
ferret on my upper arm.  He's a silver with forget-me-nots around his head.
Very cute!  When he's all healed, I'll put a pic up on ferretlady.org.
[Posted in FML issue 3513]