Have you gone to the vet to see if she has a UTI? I get them chronically, and really, it sucks so bad how much you have to pee! I've never dealt with a dog with UTIs, so I don't know what to suggest.. THK just gave out with a supplement though, cheap enough to give a shot: https://shop.thehonestkitchen.com/catalog/partlist.aspx?CategoryID=128
As for the allergies, maybe feed her boiled chicken and scrambled eggs for a few days and see if she still itches to make sure it isn't foot related. If it's the grass, not sure what you can do except get her some hydroxyzine.