I have had one itchy palm and itchy sole of one foot for over ten years and like you, I am on antihistamine and creams. I tend to have very sensitive skin and don't use scented soaps and perfumed or perfunes creams and moisturisers. I use baby soap and all natural oils which do not irritate. Coming back to the itching of the hand and foot, no name as been put to it so I'm not sure if it is Scleroderma. I also get a lot of generalised skin itching especially at bedtime. My legs and back are covered with ugly dark patches which has been appearing out of the blue for over ten years also. They itch like crazy as well. I was refered to a Dermotologist who saw me a few times, tooks skin biopsy to see if I had Lupus. The itching of the soles of your feet and the palm of your hands I'm sure, is a symptom of the autoimmune syndrome. I don't know what my dermatologist concluded, except that there were some abnormalities noted from the biopsy. I stopped attended that clinic as he gave me the immpression he thought I was wasting his time. I have dark skin so said he couldn't see the patch on the hand and kept telling me that the spots on my legs were due to injury after I gave him the history of the rashes. I did remind him it is my body so I am quite aware of the origin of the rashes. I still get them, a back scratcher sleeps on my bed with me. The itching drives me crazy so I know how you feel.
Your itchiness is more than likely due to your Raynaud's. Ask your doc to refer you to a good dermatologist so you can at least get a diagnosis but yes, this is one of the symptoms of the whole autoimmune thing.