Oh gosh that's awful, are you using anything to help it? Change your washing powder? Wearing light airy cotton clothes?
I go through phases of itchy legs, lower legs drive me insane itching. It comes and goes but was terrible around 2nd tri. Certain clothes set it off or rubbing against my quilt and bubble bath.
My legs were covered in scratches, still today if i wear the same joggers it sets me off and ive been a bit itchy today. I used E45 and had cool showers and baths, really feel sorry for you as it was so painful.