Itchie skin can be from the blood vessels or nerves also, so the rheumy could check a couple of other things. Are you able to control your fingers OK, are you getting muscle twitches, etc.? Don't talk yourself into that now... tic = Benadryl makes me itch. I have to do a sack of that stuff everytime they do the monthly IVIG treatment. My legs twitch, and I get almost like "nervous", sort of like a junky you'd see on a TV show... Then I fall asleep... lol - Are your joints inflamed? I'll get to itching all over when I'm having a bad day with the back/fingers/knees/toes/etc. swelling up.
"There but for the grace of God, go I."
"... His mercy endureth for ever."