I have a site on this:
www.geocities.com/woflysluv/allergies.html
It has many suggestions for asthmatic and allergic people.
 
What is not on the page is information on clean air hepa filters and such
because I am unfamiliar with them.  I don't go into the new dust mite
killers you put on carpets because I don't know that they are safe for
ferrets.  If such carpet powders are not safe, then daily vacuuming with
a dust free vacuum, and steam cleaning are you best option.  I would talk
to your doctor, etc., about allergy prevention because there is A LOT you
can do.
 
As far as the sealants.... I'm an unaware of those.  I am aware of a spray
a while back that you put on animals for your allergies from "Outright"
products.  I"m not sure how well they work.  If you choose to bath your
ferrets more than once a month..... pleeeeeease at least use a mild ferret
shampoo, and use a good healthy ferret conditioner such as PPP, or vets
best products, etc..  That will help your ferret with dry skin....and there
for less dander.  I have the "Outright" Allergy Relief from Dogs product.
I have tried that and find its not any better than taking other actions.
Possibly the product has one for Cats that may be more appropriate.  I am
leary of using too much of anything because if you ruin a ferrets coat and
it sheds more you are in trouble.  If you hurt and dry out a ferrets skin
they will flake and have more dander not to mention scratch more and leave
more dander.
 
I would focus on the environment even more than the actual ferrets in
prevention.  By this I mean cleaning the cage and any ferret laundry every
day.  I mean keeping the ferrets out of your bedroom, etc... as that is
where you spend half your life.  My site has many tips on there to use ...
 
Wolfy
Please visit:
http://www.geocities.com/wolfysluv/
For information on deafness in ferrets:
http://www.geocities.com/wolfysluv/deaf.html
[Posted in FML issue 3176]