Complex regional pain syndrome, also known as reflex sympathetic dystrophy, has three stages, which are acute, dystrophic and atrophic, according to the American Academy of Orthopaedic Surgeons. Stage one generally lasts up to three months; stage two lasts from three to 12 months; and stage three occurs after one year.
The most common symptoms associated with stage one of reflex sympathetic dystrophy include increased sensitivity to touch and an unusually long-lasting constant burning sensation, advises AAOS. Increased redness and warmth in the impacted limb, as well as joint swelling and stiffness, usually follow. Accelerated nail and hair growth and excessive sweating may also develop.
In stage two, skin temperature cools, skin wrinkles disappear, swelling is more constant, and the pain is more widespread, explains AAOS. Also, stiffness and sensitivity to touch increases and fingernails become brittle in stage two. The third stage of reflex sympathetic dystrophy is marked by tightly stretched, pale, shiny and dry skin. The chance of regaining motion in the affected area is diminished in stage three, and the condition may spread to other areas of the body.
The cause of reflex sympathetic dystrophy is unknown, but symptoms often appear after surgery or illness, states AAOS. No single diagnostic test exists to diagnose reflex sympathetic dystrophy, although magnetic resonance imaging scans, bone scans and X-rays assist in the diagnosis.