I would try taking something called "wound dust" powder (farnam) and mixing it 50:50 with something called "SWAT" a little blue and white tub that is vaseline based and keeps flys off of horses. Rub this on the red areas and up the legs. I use this mix on my horses, dogs, and chickens for most anything you can think of. If it is mites that are causing this it will definitely smother and kill them. If it is from over enthusiastic scratching it will help it heal. Same thing for an insect bite, or plant irritation of some sort.