Short answer
Some people with long-lasting pain find that ordinary things like clothing, a hug, a long sit or a warm shower hurt more than they should. In 2021 an international pain task force proposed criteria to help clinicians recognise this pattern, called nociplastic pain, where the nervous system itself seems to be more sensitive than usual.
A patient of mine mentioned once, almost as an aside while she was putting her shoes back on, that she'd stopped letting her grandchildren hug her because it hurt. She hadn't told anyone because it seemed small and a bit silly next to the back pain she'd come in with. It's exactly the kind of detail I want to hear about in the consulting room, and in 2021 a group of international pain researchers built details like it into a set of clinical criteria.
Three ways pain can be produced
Pain researchers generally describe three broad ways that pain can be produced. Nociceptive pain comes from tissue that is injured or inflamed, like a sprained ankle or an arthritic knee. Neuropathic pain comes from damage or disease affecting the nerves themselves. The third, nociplastic pain, was added by the International Association for the Study of Pain in 2017. It describes pain where the tissues appear normal and the nerves show no sign of damage, and yet the nervous system seems to be handling signals differently, so it can produce more pain, over a wider area, than the tissues would explain.
If you've read my post on pain when the scan is clear, you'll recognise this as the alarm that can stay switched on when nothing is broken. That post was mostly about whether this kind of pain is real, which it is, so this one moves on to how it might be recognised during an ordinary consultation.
Why clinicians needed criteria
Before 2021 there wasn't an agreed way to decide when someone's pain fitted the nociplastic description. The research tools that can pick up these changes, such as specialised sensory testing and brain imaging, aren't available in most clinics. Some extra sensitivity is also common in ordinary injury pain, which makes the line hard to draw.
A task force of nine pain researchers from Europe, North America and Australia worked through several rounds of proposals and votes and took feedback from more than fifty other specialists and leaders in the field. They then published a set of criteria that can be worked through with questions and a hands-on examination. The criteria are based on expert agreement and are still being tested, so I think of them as a careful and useful starting point that will probably be refined as that testing comes in.
The first part of the criteria looks at the pain itself. It needs to have been there for more than three months, and it tends to cover a region, or several regions, instead of sitting on one precise spot. It also can't be fully explained by an injured structure or a damaged nerve, although having one of those doesn't rule nociplastic pain out, and more on that further down.
What the examination looks like
The second part happens on the treatment table, and the tools are simple. Each one shows whether the area responds to an ordinary stimulus with pain:
- a soft brush or a piece of cotton wool stroked lightly over the skin;
- firm fingertip pressure;
- a metal object at room temperature, and the same object warmed in water.
After each one I'll ask whether the feeling lingers once the stimulus has stopped. I'll often check areas away from the sore spot as well, since sensitivity that spreads beyond the painful region is typical of nociplastic pain.
None of this is something to try at home and read into. A single test only means something alongside the history and the rest of the assessment, and even in the consulting room it takes clinical judgement to put the pieces together.
The everyday clues
The third part is where the everyday questions come in. The authors suggest asking whether the painful area has become sensitive to touch, pressure, movement, or heat and cold, and the examples they give are very ordinary:
- clothing brushing against the skin can feel unpleasant or painful, and so can the pressure of a belt, a handbag strap or a bra;
- some people find hugs painful, and some find it hard to sit in a chair for any length of time;
- a warm or cool bath or shower can make the pain worse.
Walking is a useful question as well. For most people a walk at a comfortable pace tends to ease pain a little. When walking or similar activity reliably makes pain worse, and nothing in the joints or tissues explains it, the authors treat that as a sign that the system which normally turns pain down may not be working as well as it could. It can tell me something about what your system is doing, and it's one of the reasons exercise for persistent pain tends to be built up gradually.
The fourth part looks beyond pain. People with nociplastic pain often notice that bright light, loud sound or strong smells bother them more than they used to. Poor sleep with frequent waking, tiredness, and trouble concentrating or remembering things are common too. The authors point out that the sleep, tiredness and concentration problems aren't specific to this kind of pain on their own, which is why they're weighed together with everything else.
When it's arthritis and something more
One of the more useful points in the paper is that these types of pain often overlap. The authors describe nociplastic pain sitting on top of joint or injury pain as very common. They suggest that having joint pain for a long time appears to be one of the things that raises the risk of the nervous system becoming more sensitive. Their examples include someone with a worn hip who develops widespread aching well beyond the hip. Another is someone with rheumatoid arthritis whose inflammation is well controlled but whose joints stay tender and whose muscles ache across the arms, legs and back.
So a worn knee and pain that has spread well beyond it can both be real and happen at the same time. The spread doesn't necessarily mean the joint is getting worse, and for some people that's a reassuring thing to hear. The same idea sits behind the question of whether pain always means damage, which I've written about separately.
Possible, probable and why there's no definite grade yet
The criteria give two grades:
Possible nociplastic pain
the pain fits the first part, and the examination shows the sensitivity described in the second.
Probable nociplastic pain
the everyday history and at least one of the other symptoms are there as well.
These grades describe how confident the clinician can be about the mechanism behind the pain, and they say nothing about whether the pain is real.
There's no "definite" grade for this kind of pain yet because there's no reliable test for it yet, and I think it's important to understand that. The authors say a definite grade should be considered if reliable tests are developed and validated in future. They're also clear that nociplastic pain names a mechanism and isn't a new diagnosis, so it can sit alongside a diagnosis like osteoarthritis or fibromyalgia without replacing it.
What it can change
The authors suggest that people with nociplastic pain are likely to respond better to treatment aimed at the nervous system as a whole than to treatment aimed only at the sore area. They encourage clinicians to explain the idea simply, so that people can make sense of their pain and see what can be done and what they can do themselves. They also suggest the term can help communication and validate a person's experience of pain.
In my own practice that tends to mean explaining what the nervous system is doing, looking at sleep, and building activity back up through graded exposure and exercise. Hands-on care can still have a place inside that plan when it helps someone move more comfortably. That's my clinical view and not something this paper tested, and the right mix tends to differ from one person to the next.
Coming in with this kind of pain
If some of this sounds familiar, the first appointment is mostly a conversation. I'll ask about your pain and also about the things that can seem unrelated, like your clothes, your sleep and your shower. Then I'll examine you and talk through what I think is going on, what the options are, and where your GP or another practitioner might fit in.
I can't promise that the picture will turn out to be nociplastic pain or that any particular approach will help. You can expect a clear explanation and a sense that you were listened to. What you decide to do next is your decision to make, whether that's working with me, with your GP or with someone else.
Composite of several consultations, not a single patient.
