I had a bad season with scratches a couple years ago. After sundry and
various ointments not making things better (hydrocortizone-making it
worse!) on the recommendation of another rider, I got powders of sulpher
and mixed that with Desitin. It worked but was messy. I had to soak scabs
off with epsom salts and warm water then dry the area real well and apply
the mixture. I leave it on for a 1 day then soak, wash, dry, and reapply.
Took about a week to start healing.
Now I keep fetlocks closely clipped starting in spring as soon as the snow
is gone and watch carefully for anything.