CRPS is an uncommon form of chronic pain that usually affects an arm or leg. Complex regional pain syndrome typically develops after an injury, surgery, or stroke.  There are often skin and temperature changes (swelling, warm or cool skin), nail and hair changes can be seen if CRPS affects the foot or hand.


Many cases of complex regional pain syndrome occur after a forceful trauma to an arm or a leg, such as a crush injury, fracture or amputation. Other major and minor traumas — such as surgery, stroke, infections and even sprained ankles — also can lead to complex regional pain syndrome. Emotional stress may be a precipitating factor, as well.

The entity is not completely understood, but there is belief that “neurogenic edema” or inflammation around superficial nerves can sensitize these nerves and change the perception of pain.  The pain cycle becomes dysfunctional.


Symptoms may change over time and vary from person to person. Most commonly, pain, swelling, redness, noticeable changes in temperature and hypersensitivity (particularly to cold and touch) occur first. Over time, the affected limb can become cold and pale and undergo skin and nail changes as well as muscle spasms and tightening.  Boney destruction can occur.


Procedural options include nerve blocks (including stellate ganglion blocks).  Some practices are experimenting with lidocaine or ketamine infusions.