Does anybody know any home remedies for allergic reactions?

I am asking because I don’t have health insurance right now. I have no idea what I am allergic to. My arms and back itch like crazy every night, then I end up with itchy welts. I’ve tried baking soda paste, otc hydrocortizone cream, and benadryl. I just want to stop the itching. I seriously hope that there is somebody that knows something.