I get asked this question a lot in the clinic. The great news is that in the vast majority of cases, there is no sinister cause for lower back pain, we term these cases “non-specific” or “mechanical” lower back pain; implying a non-specific cause, as opposed to serious or specific causes, such as infection. Most cases of non-specific lower back pain resolve after 6-8 weeks and may not even require any treatment. Non-specific lower back pain is an extremely common condition with estimates of prevalence in the developed world to be around 60-70%. However, lower back pain can have a more specific cause and it is important to rule out potential specific causes of lower back pain. 

What is specific lower back pain?

The term “specific” in this case refers to a cause of lower back pain caused by a specific pathology. Specific lower back pain can be very dangerous and even life-threatening, but this is not always the case. Some specific pathologies may just require different treatment than non-specific cases. 

Some examples of specific pathologies are: 

  • Cauda Equina syndrome 
  • Fracture
  • Cancer 
  • Infection
  • Spondyloarthropathy (inflammatory issues)
  • Organ related pain (e.g. kidney)
  • Shingles (viral)

How is specific lower back pain ruled out?

Enter the “red flag”. Red flags are symptoms that, if one were to present with, increase the risk that the lower back pain is something specific. Clinicians will take a full history of the issue that may uncover some initial red flags, clinicians will also ask very specific questions that directly rule in or rule out red flags. Red flags, however, are questioned in their efficacy and I would say that like many things, not all red flags are created equally with some having more weight on clinical reasoning than others. The most pressing issue with red flag screening is the sheer amount of them that exist. Currently, there are over 100 red flag symptoms and some are as simple as pain that has occurred for longer than 6 weeks or the condition is painful at night (a very common issue in mechanical pains). Clearly then, false positives are rife. Therefore, the presence of a red flag is not necessarily indicative of a more serious/specific issue, more than one red flag is generally a better marker. That being said, certain red flags, even in isolation do weigh much more heavily on clinical reasoning. These should not be ignored and would warrant a need for further investigation such as MRI scans, blood tests, etc; in some cases immediately. Below is a list of symptoms that if you experience with an episode of lower back pain, you should attend A and E immediately: 

  • Bladder or bowel symptoms – bladder is of particular importance here, incontinence is the early warning sign, followed by retention (unable to urinate). 
  • Saddle paresthesia – numbness or changes in sensation in the area that comes into contact with a horses saddle while sitting (inner thighs, perineum, genitals etc). 
  • Sexual dysfunction – the inability to gain or maintain an erection for a male and a change in sensation internally or during intercourse for a female.
  • Worsening neurology – symptoms of numbness, pins and needles or reduced muscle strength (may present as changes in gait) are progressively getting worse. E.g. leg numbness goes to numbness + weakness or numbness and or weakness spreads to the other leg 
  • Bilateral leg pain – feelings of pain, numbness, pins and needles or decreased muscle strength in both legs.
  • Fever
  • Injectable drug use 
  • Significant trauma (e.g. car accident) especially when paired with bone issues (osteoporosis), long term corticosteroid use and an age of over 70
  • A history of cancer **


A history of cancer is the most variable on this list and would most likely not involve an urgent A and E appointment. This would all depend on what kind of cancer, how long ago the patient had the disease (or if it’s concurrent), the aggressiveness of the cancer and the treatment given. The most likely cancers to spread to the spine are breast, lung and prostate. The more recent the cancer diagnosis, the more likely it could spread, for example, a recent history would be defined as having cancer within the last 5 years and this would certainly warrant further investigation as opposed to a cancer diagnosis 30 years ago which may not. If you do have a history of any type of cancer and start having back pain then you must make an urgent GP appointment. 

Wrapping up 

In essence, the vast, vast majority of lower back pain is self-limiting, not dangerous and benign (but obviously can be severe). Very, very rarely do cases require urgent medical attention. To rule out specific pathology (whether it be dangerous or not), it is important to consult with a medical professional about your issue, this can be your GP, nurse or physiotherapist.  If you have any concerns make an appointment to speak to a professional.