What characterizes complex regional pain syndrome?

Chronic pain: Complex regional pain syndrome or crps is chronic pain syndrome which can affect any part of the body including the arm or legs. It has been speculated that it is a dysfunction of the nervous system but understanding of this problem is poor at best. The treatment tends to be similar to other chronic pain disorders.

CRPS: Complex regional pain syndrome is an uncommon form of chronic pain that usually affects an arm or leg. Complex regional pain syndrome typically develops after an injury, surgery ... The pain is out of proportion to the severity of the initial injury, if any. The cause of complex regional pain syndrome isn't clearly understood.