Hello, I Am A 32 Yr Old Female And For

Hello,
I am a 32 yr old female and for the past year I have been getting what seemed like random episodes of hives for seemingly no reason. I do have allergies to some insects so I am familiar with hives. I had several rounds of skin allergy testing with no new results. The last 5 or 6 months I have noticed that it comes around right before my period. It even happens, or causes, with spotting or break through bleeding. The last 2 months the hives have been SEVERE, almost completely covering both my legs and one shoulder at one point. I was diagnosed with asthma shortly before the episodes started and the hives occasionally affect my breathing. No one seems to know what this is. Please help.