<< the picture I saw at this site showing "sarcoptic mange" looks very
 similar to what is happening to her. Does anyone know anything
 about this? >>

I just went through a bout of sarcoptic with my 13-year-old Collie, Chelsea.
She had been losing all her hair, itching, etc.  I took her to the vet a
couple of times, they did skin scrapings, even looked specifically for
sarcoptic mites, but found nothing, so gave me some things to treat her with.
 These made no difference -- she continued to get worse.  I took her back,
and this time the vet said that even though she still couldn't find a trace
of the sarcoptic mite, all the symptoms pointed to it, so she was going to
treat it as if it were.  Other breeds can simply get a couple of ivermectin
shots and it clears right up.  Collies because of their sensitivity to
ivermectin, have to be dipped the old-fashioned way (a series of four or so
weekly dippings).  Within a couple of weeks Chelsea had stopped itching, was
regrowing hair, and now has all her coat back and looks better (and feels
better) than she has in a long time.  A Sheltie I have who was showing
similar symptoms (again with scrapings revealing nothing) was likewise
treated and now has all his hair back and is itch-free.  It's certainly worth
looking into with the thought it might be sarcoptic, even if skin scrapings
don't immediately reveal it.  A Rottweiler owner friend of mine (whose place
is where Chelsea and the Sheltie probably picked it up), likewise had big
itching problems with the skin scrapings revealing nothing.  After the couple
of shots, the problems cleared up, and at that point her vet did find one
dead mite -- the only sign of one throughout the ordeal.

Linda R.