Look at any new soaps, lotions, perfumes or laundry detergent you are using. I went thru the same thing, and
only itched
at night, I changed my liquid bathsoap and the itch went away. It may also just be dry, itchy skin and there are lotions made specifically to help with the itchiness associated with this. While antihistamines calm the itch, they also calm you, so it makes it difficult to know if it's easing your anxiety and you stop itching, or it only eases your itching, or both.