My sister has CRPS and her hands are always very cold, as well as painful. What causes this cold feeling?

Complex regional pain syndrome, or CRPS, isn’t completely understood yet by doctors. Besides not knowing why it happens – usually following what could be a minor injury to an arm or leg – they don’t know how to treat the resulting symptoms and effects.

One effect of CRPS is reduced blood circulation. When the blood vessels constrict or narrow, the blood can’t circulate as it should. This can cause the body part can feel cold.