APA Dictionary of Psychology

a chronic, often debilitating pain disorder characterized by persistent, regional pain, most commonly affecting a limb, that is disproportionate to the inciting injury or event and extends beyond the expected area of tissue damage. The condition is associated with various sensory disturbances (e.g., hyperalgesia, allodynia), motor dysfunction (e.g., weakness, tremor, dystonia), and abnormalities in skin blood flow, color, and sweating. Complex regional pain syndrome encompasses type I (without confirmed nerve injury, formerly known as reflex sympathetic dystrophy) and type II (with nerve injury, formerly known as causalgia).