I don't know what to call it but I get it too. Prior to being diagnosed with lupus I always assumed it was contact dermittis.
I seem to always get it at the same spots including top of feet,back of knees,above knees on thigh,hands,back of arms, face etc.
Steroid creams cause me to peel -so I use gold bond anti-itch lotion and sometimes aloe-vera helps.
This can be extremely painfull,I certainly sympathize with you!
I found it helps to sleep with cotton gloves and socks on,as I have a tendicy to scratch in my sleep.
After having been on plaquenol for 15 mos. and doing a better job of staying covered in the sun I find that I do not get as bad a rash as I used to.