I have that problem with my fingers and Toes - my Rheumy has diagnosed it as Raynauds Disease (google it and you will find ton's of info). My toes and fingers will get bright white and very PAINFUL that I literally can't feel much, not even hot water.
It is worse in the winter than in the summer, unless I am spending a lot of time in very cold A/C rooms.
Diagnosed with Lupus - April 2002
Diagnosed with Crohn's Disease - January 2003 (problems since early 1990)
Meds: Flexeril 10mg as needed, Plaquenil 200mg, Probiotics, Multi-vitamin, fish oil, Cal/Mag Supplement
Off Immuran as of April 1st and doing well!!