Complex regional pain syndrome (CRPS), also known as reflex sympathetic dystrophy (RSD), is a long term condition that often worsens with time. It is characterized by severe pain and sensitivity, swelling, and changes in the skin. It may initially affect one limb and then spread throughout the body; 35% of people report symptoms throughout their whole body. Treatment is complicated, involving medications, physical and occupational therapy, psychological treatments, and neuromodulation and is often unsatisfactory, especially if delayed.