FAQ Complex Regional Pain Syndrome (CRPS)

What is Complex Regional Pain Syndrome (CRPS)?

Complex Regional Pain Syndrome (CRPS) Houston

Complex Regional Pain Syndrome (CRPS) is a chronic disease that was formerly known as causalgia, reflex sympathetic dystrophy (RSD), reflex neurovascular dystrophy (RND) or amplified musculoskeletal pain syndrome (AMPS). There are two types of CRPS:

  • Type I covers RSD, Sudeck’s atrophy, and RND. This subtype of CRPS has no associated nerve lesions.
  • Type II CRPS is associated with obvious nerve damage and was formerly known as causalgia. This subtype has more severe pain symptoms and is more difficult to treat.

CRPS presents with severe pain, stiffness, swelling and discoloration that affects the limbs. Some patients may also present with “burning pain” especially in chronic conditions. This is more common on the hands, although feet and even legs and arms can also be affected. There are three stages to the disease:

  • Stage I (Acute) – the initial symptoms in the acute stage are burning pain and sensitivity to the touch. This is usually followed by swelling and stiffness, as well as warmth to the touch and redness (occasionally). Stage I is expected to last up to 3 months.
  • Stage II (Dystrophic) – this is marked by an increase in the swelling and the spread of the pain. Stiffness and sensitivity of the affected area also worsen. This stage lasts from 3 to 12 months.
  • Stage III (Atrophic) – After a year, the skin becomes dry, pale and shiny. At this point, stiffness and swelling have already affected the functionality of the limb, making it less likely for the patient to return to normal function. CRPS may have also spread to other parts of the body.

Despite its relative severity, CRPS is an uncommon condition and most people are not aware of it.

What causes CRPS?

Complex Regional Pain Syndrome (CRPS)The exact cause of CRPS is unknown. There is a theory that posits that CRPS is a result of central and peripheral dysfunction of the nervous system. There is also noted hyperactivity of the immune response, which may contribute to the sensitivity and pain. CRPS Type I has also been shown to affect brain structure in the prefrontal and motor cortices, which suggest involvement in pain-related and emotional pathways of the nervous system.

CRPS most commonly follows surgery; however, the condition may be triggered by a host of other incidents such as after a tetanus toxoid injection and infection.

How is CRPS diagnosed?

The diagnosis of CRPS follows a medical history and physical examination. There is no single test that conclusively diagnoses CRPS. However, imaging studies such as X-rays, CT scans and MRI scans may help rule out differential diagnoses.

How is CRPS treated?

Reflex Sympathetic Dystrophy

There is no known cure for CRPS, although pain medications may provide relief to the more aggravating symptoms and alleviate patient suffering.

Medications can be prescribed to provide anti-inflammatory and analgesic relief. These can include NSAIDs, oral corticosteroids, and opioid analgesics. Novel treatments include the use of phenoxybenzamine and Immunoglobulin G, which have been shown to be promising, although further studies are needed.

If non-surgical treatments fail, then you can opt for surgical procedures. The stimulation of the spinal cord has been shown to improve pain relief, although the procedure is known to be technically challenging.

What are the symptoms?

Prolonged, often constant, pain is the main CRPS symptom. Some patients may experience extremely severe, uncomfortable, and debilitating pain in the affected area, causing long-term disability. It may feel like a “pins and needles” type of burning sensation. In initial stages, the patient feels as if someone is squeezing the affected limb, with increased sensitivity that even light touch feels uncomfortable. Gradually, the pain may spread to the leg or arm and even shift to the opposite extremity.

Other common symptoms include:

  • altered nail/hair growth patterns
  • changes in skin texture, which may appear thin, shiny
  • stiffness in affected limbs
  • increased sweating in the affected limb
  • tremors/jerking of the affected limb
  • coordination problem in muscle movement, with reduced ability in moving the affected body part
  • constant chronic burning sensation/pain

Some patients may experience sensitivity to light and sound, irregular heart rhythms, digestive issues, bladder problems, memory loss, gynecologic problems, and compromised immune system.


Birklein F, Drummond PD, Li W, et al. (2014). Activation of cutaneous immune responses in complex regional pain syndrome. The Journal of Pain. doi: 10.1016/j.jpain.2014.01.490

Grothusen JR, Alexander GM, Erwin K, Schwartzman RJ. (2014). Thermal pain in complex regional pain syndrome type I. Pain Physician. Retrieved from: http://www.ncbi.nlm.nih.gov/pubmed/24452647

Inchiosa MA Jr. (2013). Phenoxybenzamine in Complex Regional Pain Syndrome: Potential Role and Novel Mechanisms. Anesthesiology Research and Practice. Retrieved from: http://www.ncbi.nlm.nih.gov/pubmed/24454356

Pleger B, Draganski B, Schwenkreis P, et al. (2014). Complex regional pain syndrome type I affects brain structure in prefrontal and motor cortex. PLoS One. doi: 10.1371/journal.pone.0085372

Van Buyten JP, Smet I, Liem L, et al. (2014). Stimulation of Dorsal Root Ganglia for the Management of Complex Regional Pain Syndrome: A Prospective Case Series. Pain Practice. doi: 10.1111/papr.12170