<< I had a battle with scratches on and off for a couple of years
 trying everything. Finally I used Novelsan, I got it from Jeffers
 Supply. You throughly clean area with warm water to soften 
 scabs.Then with finger nails slowly scratch scabs off.Then
 with clean cloth remove matter.Then put another clean layer of
 Novelsan on and leave it.Do it once a day until scabs are all gone.
 Once the scratehes cleared up I never had the problem again
 MARCY >>
Horse can develope am immunity to scratches.  But it may not last more than a
season.  Somehting like Poison Ivy. I get a bad case one year and then I
don't get it for a couple of years, then it comes back.
Teddy