Unfortunately the natural course of CRPS is to become progressively worse over time. Many things can cause pain to increase but as Bram so well said it doesn't necessarily mean that it is spreading.. could just be what they call a pain "flare". How do you tell the difference.. well quite honestly I don't think there is anyway to determine if it is spread except by time. Sad. What can you do? Well first off try to relax, get her into a warm bath with epsom salt, some candles and relaxing music. Kick back and watch a good movie or curl up and read a book anything that will help her relax and distract her from the pain is good. Does she currently have medications to help control pain? Who is her doctor?? It would be better to see if you can see her treating doctor rather than waste your time at an ER as they aren't usually helpful and often only make things worse with the additional stress and lack of knowledge. Plus most ER's don't treat chronic pain anymore and will just look for acute injuries and send you on your way. Sad. A warm gentle moist compress can also be beneficial. Massage on her unaffected arm/body will help with relaxation and tension. Go for a walk.. I know she is in pain and that sounds crazy but honestly the fresh air and distraction will do her good.

She is lucky to have you!

Tessa