Lower back pain: when to see a physio, when to see a GP (red flags)

Most back pain is not serious

In primary care, around 90% to 95% of back pain is classed as non specific, meaning there is no single structural cause that a scan or test would find. Between 5% and 10% involves an irritated nerve root (sciatica), and less than 1% is caused by a specific spinal disease (Bardin, King and Maher, 2017).

Non specific doesn't mean the pain isn't real or that nobody knows what to do about it. It means the pain is coming from the normal structures of the back, which tend to recover well. A meta-analysis of 33 studies and over 11,000 people with new back pain found average pain scores dropped from 52 out of 100 to 23 within six weeks, and to 6 out of 100 at a year (da C Menezes Costa et al., 2012).

Pain that has already been around for a long time improves more slowly. In the same analysis, people with persistent pain only dropped from 51 to 23 over the year (da C Menezes Costa et al., 2012). That is where getting the right help early makes the biggest difference.

Why a single red flag isn't a reason to panic

Red flags are useful, but they are not perfect. In an Australian study of 1,172 people with new back pain, 80.4% had at least one red flag, yet only 0.9% turned out to have a serious cause (Henschke et al., 2009). A review in the BMJ found many of the red flags listed in guidelines change the odds of a serious problem very little, or have never been properly tested (Downie et al., 2013).

An international framework for clinicians makes the same point and recommends looking at the overall picture rather than ticking items off a checklist (Finucane et al., 2020). That is how we work in clinic. A combination of warning signs gets acted on quickly. One on its own, in someone who otherwise fits a normal pattern of back pain, usually means we keep a closer eye on things.

When to see a physio

For most back pain, a physiotherapist is a sensible first stop, and you don't need to see your GP first. You can book privately at any time, and in many areas you can refer yourself to NHS physiotherapy too (NHS, 2026).

Physiotherapy makes sense if:

• your pain is limiting work, sport, sleep or day to day life
• it hasn't eased after a week or two of keeping moving
• it keeps coming back
• you have leg pain or sciatica without the emergency symptoms above
• you want a clear explanation and a plan, rather than waiting it out

We also screen for all of the red flags in this article at your first appointment. If something needs medical attention, we'll tell you and write to your GP.

What helps back pain?

NICE guidance for back pain and sciatica recommends:

• staying active and returning to normal activities and work as you can
• exercise, including group exercise programmes
• hands on manual therapy only as part of a package that includes exercise
• psychological support alongside exercise for people who need it

NICE advises against paracetamol on its own, opioids for long term back pain, antidepressants and gabapentinoids for back pain (NICE, 2016).

NICE also recommends using a short questionnaire called the STarT Back tool at the first appointment to judge how much support someone needs (NICE, 2016). In a UK trial of 851 patients, matching care to someone's STarT Back score improved disability more than usual care, and cost less per patient (Hill et al., 2011).

Do I need a scan for my back pain?

Usually not. Disc bulges show up on scans in 30% of 20 year olds and 84% of 80 year olds who have no back pain at all (Brinjikji et al., 2015), so a scan often finds things that aren't the cause. NICE advises against routine scans outside specialist settings, and recommends imaging only when the result is likely to change your treatment, for example if surgery is being considered or a serious cause is suspected (NICE, 2016).