What Are 3 Stages of Complex Regional Pain Syndrome?

Medically Reviewed on 1/25/2023

What is complex regional pain syndrome?

3 Stages of Complex Regional Pain Syndrome
Symptoms of CRPS typically start within four to six weeks after an injury.

Complex regional pain syndrome (CRPS) is a rare clinical syndrome characterized by debilitating pain, swelling, and vasomotor dysfunction of an extremity.

CRPS frequently occurs in young adults (peak onset at about 40 years) and is more frequent in women than in men.

Types of CRPS

  • Type I
    • Formerly known as reflex sympathetic dystrophy
    • Does not include obvious nerve injury
  • Type II
    • Formally described as causalgia (a result of specific nerve damage)
    • This type occurs with documented nerve injury

3 stages of complex regional pain syndrome

The three stages of complex regional pain syndrome are as follows:

  1. Stage I: Acute
    • A stage that may last up to three months, characterized by a constant severe burning or aching pain and increased sensitivity to touch, fluctuations in skin temperature between hot and cold followed by swelling and joint stiffness along with increased warmth and redness in the affected limb.
    • Other symptoms may include faster-than-normal nail and hair growth, changes in the skin's color, appearance, and texture (pale, red, purple, or mottled, thin, and shiny), and excessive sweating.
  2. Stage II: Dystrophic
    • It can last 3 to 12 months, characterized by a more constant swelling, increased stiffness, brittle and cracked nails, weakening of muscles, the disappearance of skin wrinkles, increased sensitivity to touch, and a lower-than-normal skin temperature.
  3. Stage III: Atrophic
    • This stage typically occurs after a year of developing early symptoms (if left untreated).
    • The affected area’s skin becomes pale, dry, stiff, tightly stretched, and shiny. The muscles and tendons undergo atrophy (waste away) and contract, which can ultimately cause contractures of the affected hand or foot.

What causes complex regional pain syndrome?

The onset of complex regional pain syndrome (CRPS) is usually linked to a wide range of injuries resulting from trauma such as ankle sprain, bug bite, or after casting, surgery, immobilization, or a procedure such as venipuncture and intramuscular injection.

Although a precipitating event may not be identified in approximately 10 percent of cases, a CRPS-like syndrome may be observed in patients who have the following conditions:

What are the signs and symptoms of complex regional pain syndrome?

Both complex regional pain syndrome (CRPS) I and II have a hallmark of allodynia, severe hyperalgesia, edema, skin changes, and abnormal alterations in sudomotor and vasomotor function. CRPS type II presents with the same clinical features as CRPS type I except for typical clinical signs and history consistent with a nerve injury.

Symptoms of CRPS typically start within four to six weeks after an injury but may develop without a known and apparent cause.

The characteristics of pain in CRPS include the following:

  • Pain varies in quality from person to person, from a deep ache to a sharp stinging or burning sensation
  • Pain is aggravated by environmental (cold and humidity) and emotional (anxiety and stress) factors
  • Cutaneous hypersensitivity presents as pain in contact with clothing or exposure to a cool breeze
  • Patients with CRPS often experience allodynia (pain from innocuous tactile stimuli) and hyperalgesia (an increased response to painful stimuli)

Causes of vasomotor changes:

  • A diverse range of skin discoloration, including different hues of red and purple to mottled, ashen gray
  • The skin's glossy and smooth appearance is due to edema in the painful region
  • A difference in skin temperature (either higher or lower than 1°C) is found in 42 percent of patients with CRPS
  • In addition, sudomotor abnormalities range from hyperhidrosis to bone-dry skin

Motor disturbances in the affected limb may present with symptoms such as:

  • Tremors
  • Weakness 
  • Muscular incoordination 
  • Decreased range of movement
  • Muscle spasms
  • Compromised range of motion on the affected side
  • In severe cases, contractures may develop 
  • Dystonia
    • In the upper extremity (seen in fingers fixed in flexion or the clenched-fist syndrome) 
    • In the lower extremity (presents as an equinovarus position, which is a common foot abnormality in which the foot points downward and inward)


Pain Management: Surprising Causes of Pain See Slideshow

How is complex regional pain syndrome diagnosed?

The International Association for the Study of Pain has stated the characteristic features necessary to establish the diagnosis of complex regional pain syndrome (CRPS) type I:

  • The presence of an initiating noxious event, trauma, injury, or a cause of immobilization
  • A constant pain disproportionate to a causative event, allodynia, or hyperalgesia
  • The presence of edema, changes in skin blood flow, or abnormal sudomotor activity in the painful region
  • Exclusion of all other medical conditions that may account for the degree of pain and dysfunction
  • Motor disturbances and trophic abnormalities (altered nail and hair growth)

Additional tests to reinforce the diagnosis include:

  • Quantitative sensory tests
  • Electromyogram and nerve conduction studies
  • Autonomic tests 
    • Quantitative sudomotor axon-reflex test
    • Thermography
    • Sympathetic block
    • Doppler flowmetry
  • Trophic dysfunction (radiograph, bone scintigraphy)

How is complex regional pain syndrome treated?

The treatment of complex regional pain syndrome (CRPS) aims to decrease pain intensity, restore function to the affected limb, and maintain the quality of life.

Treatment consists of a combination of carefully managed approaches, including:

What are the complications of complex regional pain syndrome?

The complications of complex regional pain syndrome may include:

  • Infection
  • Ulcerations
  • Chronic edema
  • Dystonia
  • Myoclonus
  • Atrophy (tissue wasting)
  • Contracture (muscle tightening)
  • Cognitive executive dysfunction
  • Adrenal insufficiency
  • Gastroparesis
  • Irritable bowel syndrome
  • Limb amputation
  • Symptoms of psychological distress (anxiety, depression, fear, and anger)
Medically Reviewed on 1/25/2023
Image Source: iStock image

Complex Regional Pain Syndrome I (Reflex Sympathetic Dystrophy) American Society of Anesthesiologists https://pubs.asahq.org/anesthesiology/article/96/5/1254/40065/Complex-Regional-Pain-Syndrome-I-Reflex

Complex Regional Pain Syndrome (CRPS) Cleveland Clinic https://my.clevelandclinic.org/health/diseases/12085-complex-regional-pain-syndrome-crps

Complex Regional Pain Syndrome (Reflex Sympathetic Dystrophy) American Academy of Orthopedic Surgeons https://orthoinfo.aaos.org/en/diseases--conditions/complex-regional-pain-syndrome-reflex-sympathetic-dystrophy/

Complex Regional Pain Syndrome (CRPS) Stanford Medicine https://med.stanford.edu/pain/about/chronic-pain/crps.html