Mar, you've responded to a 7-month old thread, so the original poster is likely not going to see this.

However, there is something you can try for hives caused by the TPO antibodies which cause Hashimoto's. Exactly as Elmhar said, these antibodies are binding to your skin's mast cells and causing the allergic reaction. The key is to reduce the antibody count, and you can do that by taking enough thyroid hormone (such as Unithroid) to arrest the antibody activity. By gradually increasing the dose enough to shut off your gland's natural production of hormone, the antibodies will "think" there is no longer any thyroid tissue to attack.

Also, studies have proven that selenium supplementation can reduce TPO antibodies up to 40%. Taking 100-200 mcgs of selenium a day may be enough to improve the hives situation. Buy it in any health food or vitamin shop.

Don't expect conventional MDs to know any of this. That's why none of them has offered you much in the way of constructive help. As usual, they only know how to attempt to mask the symptoms. The most successfully treated thyroidies have learned to help themselves as much as possible.

Thanks midwest1

Sorry! I didn't pay attention to how old was the thread, I just saw somebody going to the same nightmare as I am, and I started answering. In some way, that helped me a lot. First, because you find out there are other people going to the same thing, and second because you talk to somebody that understand what is going on with you.
My endo dr gave me 0.05 mg daily of unithroid, and it's not working at all. I am going to call her today to let her know how I am.
I am getting very depressed because of the hives. The itching is horrible, I try not to scratch, but sometimes it's impossible, and when I do, the hive that started penny size, goes to a orange size, and itch even more.
I am going to try selenium and see what happens.
Thanks again, was nice of you.