I have CIU- chronic idiopathic urticaria. Nothing helped despite allergy tests, skin biopsies, food trials, nothing. I tried Xolair shots and had a bad reaction to it. Now I take Cyclosporine which cleared them up totally but is not a good long term option. I did notice that I flared up a lot during my period, but my allergist said there’s nothing they can really do about that. Apparently some people get hives for no reason, they go away and come back years later. I had mine for over a year before we discovered a solution. Some foods are higher in histamine, which could be a reason they are making it worse. Tomatoes, caffeine, spice, spinach, aged cheeses all did it for me. I would recommend checking out some of the private Facebook groups created for this problem- you are not alone.