I don't really know whether it is CRPS or not...but I CAN tell you that I often have flare ups with no trigger...or a trigger that isn't easily seen. Stress, temperature changes, pressure changes, the touch of clothing...all of these things can cause a flare up for me. Usually I can figure out what caused it...but it honestly has taken me YEARS to sort out many of the more unusual triggers. Every once in a while I still have horrible flares that seem to come out of no where...and it can take days or weeks sometimes to recover from those flare ups.