Complex regional pain syndrome is a rare form of chronic pain that typically affects an arm or a leg. The condition usually develops after an injury, surgery, stroke or heart attack.

The cause of complex regional pain syndrome is not fully understood. However, treatment for the condition is most effective when started early.



Symptoms of complex regional pain syndrome include:


  • Continuous burning or throbbing pain in the arm, leg, hand or foot
  • Sensitivity to touch or cold
  • Swelling of the painful area
  • Changes in skin temperature (sweaty or cold skin)
  • Changes in skin color (white and mottled to red or blue)
  • Changes in skin texture (tender, thin or shiny in the affected are)
  • Changes in hair and nail growth
  • Joint stiffness, swelling and damage
  • Muscle spasms, weakness and loss (atrophy)
  • Decreased ability to move the affected area


Symptoms may change and vary from person to person. Moreover, once the affected limb becomes cold and pale and undergoes skin changes and muscle spasms, the condition becomes irreversible.

Complex regional pain syndrome can sometimes spread to other parts of the body, such as the opposite limb. The pain may be worsened by emotional stress.

In some cases, symptoms of complex regional pain syndrome resolve on their own but in other cases, the symptoms may persist for months to years.



Complex regional pain syndrome can occur in two types with different causes:


Type 1

Type 1 is also known as reflex sympathetic dystrophy syndrome, which occurs after an illness or injury that did not directly damage the nerves in the affected limb. This is the more common type of complex regional pain syndrome.

Type 2

Type 2 is also known as causalgia and it involves a distinct and direct nerve injury.


Many cases of complex regional pain syndrome occur after trauma or injury such as crush, fracture or amputation. Other traumas such as surgery, heart attacks and infections can also cause complex regional pain syndrome. Furthermore, emotional stress can also trigger the condition.



Untreated complex regional pain syndrome can progress to more disabling symptoms, such as:


  • Tissue wasting (atrophy): Avoiding movement in the limbs due to pain or stiffness can lead to the skin, bones and muscles to deteriorate and weaken.
  • Muscle tightening (contracture): Untreated complex regional syndrome can lead to tightening of the muscles, which causes the hand and fingers or foot and toes to contract into a fixed position.




  • Taking vitamin C after a wrist fracture lowers the risk of complex regional pain syndrome. 
  • Early mobilization after a stroke lowers the risk of complex regional pain syndrome.