I Have Been Getting Hives From Head To Toe While

I have been getting hives from head to toe while sleeping ..I got a steroid from the doctor and some hydroxyzine for the itching but last night I had a few small hives and took some hydroxyzine and when I woke up this morning I had hives from top to bottom and it is now night again and I still have them and I am not sure what I should or can do to get some relief from the hives.