OK I've done some research and thought I might share it with you. This may not apply to you and I'm not saying you should do this or that or stop any medication you might be taking etc. etc.
The thing is that it's not a disease. Its the autonomic nervous system (three parts) not functioning properly. The sympathetic system is one part and that deals with flight and fight reacting to stress, ncreasing HR, blood pressure, raised cortisol, clotting agents and inflammation. That works in opposition to the parasympathetic system which deals with long term stuff such as immune sytsem, digestion, healing and DNA repair. As one goes up the other goes down and v.v. With Raynauds the sympathetic and the parasympathetic are out of balance with each other. The whiteness and cold is the result of extreme constriction of the blood vessels in the outer extremities of the body, i.e.hands and feet.
It would seem that chronic stress is the major cause as is the case with many diseases. I believe that understanding this is the first step in dealing with it and then to reverse the condition by taking steps to get the body adapted to relaxing maybe even doing some meditation. In the short term if you start feeling cold which is a precursor to the condition, then it might help to put extra layers of clothing on.
When my hands went white in the car I was dropping off a return to Amazon to a collection point using a new system for the first time and I was unsure where to go and lookng back I was stressed for sure.