The main symptom of complex regional pain syndrome (CRPS) is pain, which can sometimes be severe, continuous and debilitating.

It's usually confined to 1 limb, but can sometimes spread to other parts of the body.

The pain of CRPS is usually triggered by an injury. But the pain is a lot more severe and long-lasting than would normally be expected.

The pain may feel like a mix of burning, stabbing or stinging. There may also be tingling and numbness.

You may have periods of pain lasting a few days or weeks, called flare-ups, where the pain gets worse.

Stress in particular can lead to flare-ups, which is why relaxation techniques and mindfulness training can be an important part of treating CRPS.

If you have CRPS, your skin in the affected area can become very sensitive.

Even the slightest touch, bump or change in temperature can cause intense pain.

You may hear this described in the following medical terms:

• hyperalgesia – feeling more pain than usual to something that is painful
• allodynia – feeling pain from something that does not usually cause pain, such as a light touch or pressure to the skin

In addition to chronic pain, CRPS can also cause a range of other symptoms.

These can include:

• strange sensations in the affected limb – it may feel as if it does not belong to the rest of your body, or it may feel bigger or smaller than the opposite unaffected limb
• alternating changes to your skin – sometimes your skin in the affected limb may be hot, red and dry, whereas other times it may be cold, blue and sweaty – changes to skin colour may be harder to see on brown and black skin
• hair and nail changes – your hair and nails in the affected limb may grow unusually slowly or quickly and your nails may become brittle or grooved
• joint stiffness and swelling in the affected limb (oedema)
• tremors and muscle spasms (dystonia)
• difficulty moving the affected body part
• difficulty sleeping (insomnia)
• small patches of fragile bones (osteoporosis) in the affected limb – although there's no evidence this could lead to fractures

Very rarely, CRPS can also lead to further physical complications, such as:

• skin infections and open sores (ulcers)
• muscle atrophy, where the muscles begin to waste away
• muscle contractures, where the muscles shorten and lose their normal range of movement

Some of these problems can make it very difficult for people with CRPS to move around.

The emotional strain of living with chronic pain can sometimes lead to psychological problems, such as depression and anxiety.

During periods of extreme pain, some people may even have suicidal thoughts.

See a GP as soon as possible if you have been experiencing depression or had suicidal thoughts. They'll be able to provide help and support.

Or you can call the Samaritans on 116 123 or email jo@samaritans.org.

They're available 24 hours a day to talk through any issues you may be experiencing in total confidence.

You should see a GP if you have persistent pain that's preventing you from carrying out everyday activities.

CRPS can be difficult to diagnose. It's best to get help as soon as possible because early treatment can help reduce your painful symptoms.

Find out more about diagnosing CRPS.