How is CRPS diagnosed?


The journey to a CRPS (Complex Regional Pain Syndrome) diagnosis is often long, challenging, and filled with uncertainty. You’re not alone in having a hard time with the process, and the challenges are not your fault. Understanding the various obstacles can empower you to advocate for yourself and navigate this complex process more effectively.

Why is the diagnosis process complicated?

  1. No Single Clear Test for CRPS:  Many common medical conditions have a straightforward single test that lets you know whether you have the condition (like a throat swab for strep throat or a blood test for detecting diabetes).  But it’s not like this for CRPS. There is no single test that gives a clear answer.

  1. Rule-Out Process:  The diagnostic procedure for CRPS often involves checking and ruling out several other medical conditions. This can lead to a long series of tests, some of which might be invasive, expensive, or require waiting.  This all adds more stress to the process.

  1. CRPS Varies from Person to Person:  CRPS looks different in different patients. The differences in symptoms, their intensity, and duration can make it a moving target, even for seasoned medical professionals.

  1. Doctors Not Fully Up to Date on CRPS: Many medical professionals are not up-to-date with the latest diagnostic process for CRPS.

  1. Minimization of Non-Visible Symptoms Like Pain:  There's a longstanding history in medicine of minimizing or even dismissing pain (since pain can’t be seen). Patients with CRPS, whose primary complaint is pain, might be invalidated by some medical professionals in their journey for answers.

  1. Enduring Pain While Seeking Answers:  CRPS patients face a double challenge: they're dealing with intense physical pain while also navigating a complicated process to get a diagnosis. This double struggle—experiencing the pain and trying to get it diagnosed—adds to the stress and frustration. Feeling unheard or misunderstood can amplify distress even further.

How do doctors diagnose CRPS?

In 2019, top pain experts gathered in Spain to clarify the CRPS diagnosis process. This most updated diagnosis process (as of 2024) is called the “Budapest Criteria” or the “IASP criteria” (these both mean the same thing). Make sure to ask your doctor if they are using this process to diagnose your CRPS

The Checklist for Diagnosing CRPS

The following 4 rules (A-D) are generally required to diagnose CRPS. (However, as described above, a diagnosis of “CRPS-NOS” may be given to people who only have some of these)

A) Duration of pain - The pain has been in a limb and has lasted or keeps coming back for over 3 months.

B) Symptoms - Notice on your own that you have at least 3 categories of symptoms.  Symptoms are things you feel or notice in your body (e.g. pain in a limb).

C) Signs - Doctor observes that you have at least 2 categories of signs.  Signs are things a doctor can observe (for example swelling or temperature changes in a limb)

D) No better diagnosis - Doctor rules out other conditions that may better explain the symptoms

The four categories of symptoms / signs

Patient needs to notice / feel things in 3 of these categories, and doctor needs to observe things in 2 of these categories.

Category 1:⚡ Pain in response to light touch or temperature or deep pressure or movement or pinprick

Category 2:🎨 🌡️ Skin color or temperature is abnormal in the affected body region

Category 3:💧 Abnormal sweating or swelling in the affected body region

Category 4:💅🏾 Weakness, tremors, or stiffness. Or changes in hair or nail growth. Or changes in skin texture (like shiny skin).

The 4 Types of CRPS

When making diagnosis, doctors will often categorize the CRPS into one of these four categories:

1. CRPS type I - CRPS symptoms without a clear nerve injury

2. CRPS type II - CRPS symptoms with a clear nerve injury

3. CRPS-NOS (Not Otherwise Specified) - A person who has some of the symptoms of CRPS. Even though they don’t fulfill all the criteria for CRPS, there is no other diagnosis that better explains the symptoms.

4. CRPS with Remission of Some Features - A person was formerly diagnosed with CRPs but now some of their symptoms have resolved.

Important Tip: In terms of treatment, there is very little practical difference between these categories - they are all treated similarly.

Rule out process

There are numerous medical conditions with symptoms that are similar to CRPS. When making a CRPS diagnosis, doctors will first check if the symptoms are actually being caused by a different medical condition. 

Your doctor may recommend various tests. These tests can produce valuable information.  However, none of these tests are “perfect” for deciding whether someone has CRPS or not.

  • Sometimes these tests come out normal even when someone has CRPS.
  • Sometimes these tests come out abnormal even when someone doesn’t have CRPS.

These tests are used in combination with clinical judgment and assessment of symptoms. And for many people, it's not necessary to have all these tests.

  • Thermography:  Measuring the temperature of different parts of the body once, or on a daily basis and comparing the painful side of the body to the non-painful side of the body
  • Radionuclide Bone Scintigraphy:  An imaging test that utilizes a very small amount of radioactive material to check for bone abnormalities even before they would show up on a regular x-ray.
  • Electromyography (EMG):  Checks the health of the body’s nerves and muscles and measures the speed of how fast nerve signals travel through the body.
  • Musculoskeletal Ultrasound:  Uses sound waves to produce a picture of muscles, tendons, ligaments, and joints, which helps check for inflammation, swelling, or other abnormalities.
  • Skin Biopsy:  A procedure where a small piece of skin is removed and examined under a microscope, which can help determine abnormalities in nerve fibers in the skin

Sources: "The Valencia consensus-based adaptation of the IASP complex regional pain syndrome diagnostic criteria." Pain 162.9 (2021)