I would definitely ask your vet to do a skin scrape and send it out to a
lab.  Lots of things could cause what you describe, but my guess would be
one of three.
 
1. Mange/scabbies.  This is generally treated with an injection of
Ivermectin by the vet.  You will also need to launder/scrub/disinfect every
surface they have touched.  This is highly contagious, and every animal
in your home will need to be treated.  PS--you can also get scabbies, you
might need to treat yourself too, see your personal doctor.
 
2. Kidney problems.  I don't know why the relationship exists, but have
been told by a vet that skin problems as you describe are often a sign of
kidney problems.  Generally you'll need to do a blood and urine test to
rule this out.
 
3. Blowing a coat and scratching themselves raw.  This is very unlikely, I
would investigate the other options first.
 
Anne
[Posted in FML issue 3130]