I was so itchy all over by like 20 weeks, that I went to extreme measures.
We threw alway ALL of our soap/bodycare stuff. DH made me a bunch of soap that is just Cocoa butter. NO FRAGRANCES!! I only use it on my "hot spots", armpit, crotch, under breasts, face, and rinse the rest of my body with water. I stared taking cooler showers and only showering every other day at most. I bought straight coconut oil and cover by whole body in it (even "down there"

) every time I shower. Olive oil was working too, but it was greasier, and I smelled like a salad. I also made some laundry soap out of the soap DH made me, and my clothes are wonderful.
My skin was so not itchy, in about 3 days, and it hasn't started again. Even though it is this awful dry time of the winter. I think the key was getting a pure moisturizing soap with no fragrances and using the straight oil. FWIW DH decided to do it with me, and his skin is wonderful too. He is a guy that usually uses too much soap and NO moisturizer and gets dry in the winter.
Hope you feel better!
And the only thing that got rid of the really bad crotch itch was clotrimiolze. Definitely got it from DH. And keeping the hair down there trimmed very short. (Way too much moisture right now!)