Another home remedy to try is to add baking soda to your bath water and soak for awhile. I had shingles MANY years ago and the doctor recommended it for the itch. Then I had hives a couple of years ago and tried it. Again, it worked. Of course I stayed clean because I was taking 2+ baths per day. You problem might not respond to this due to the cause, but it might be worth a try. It is cheap and easy.