So glad to see this post (but certainly not glad for your itching!) I have RSD in my left foot, but since the onset I've had insane level itching in a tattoo near my right ankle. The entire tattoo actually swells and you can almost feel the outline like brail and it itches SO bad that I've left sores on my skin! I thought it was strange that it started at/or about at the same time as the RSD, so maybe it is related after all? - and Im not the only one having these itching areas! I do lotion and I've even tried benadryl cream.
Aquafor(spelling?) has worked best for me.