Why Ankylosing Spondylitis Takes Years to Diagnose, and How to Speed It Up
Ankylosing spondylitis (AS), now often called axial spondyloarthritis (axSpA), is notorious for how long it takes to diagnose. In the UK the National Axial Spondyloarthritis Society (NASS) puts the average delay at around eight and a half years from first symptoms. If you're somewhere in that gap, here's why it happens and what can move things along.
Why it takes so long
- Back pain is common. Most back pain is mechanical and gets better, so inflammatory back pain is easily mistaken for the ordinary kind.
- It starts young. Symptoms usually begin in the late teens to thirties, an age when serious back conditions aren't high on anyone's list.
- Early X-rays can be normal. Damage to the sacroiliac joints can take years to show on X-ray. MRI can show inflammation much earlier, but isn't always requested.
- Blood tests can be normal too. Inflammation markers such as CRP are raised in only some people, and the HLA-B27 gene is common in people with AS but also carried by many people who never develop it.
- Women are often missed. AS was long thought of as a men's disease, and women tend to wait longer for a diagnosis.
The signs of inflammatory back pain
These features point towards inflammation rather than a strain or a disc problem:
- back pain that started before 40 and came on gradually
- pain that has lasted more than three months
- stiffness in the morning that takes a while to ease
- pain in the second half of the night that wakes you
- pain that gets better with movement and worse with rest
- alternating buttock pain
- a big improvement within a day or two of anti-inflammatory painkillers such as ibuprofen
Other clues include painful heels or tendons, a swollen joint, psoriasis, inflammatory bowel disease, an episode of uveitis (a painful red eye) and a close relative with AS. In the UK, NICE guidance asks GPs to refer people to a rheumatologist when back pain started before 45, has lasted more than three months, and several of these features are present.
What helps speed things up
- Name the pattern. Say "I think this might be inflammatory back pain" and describe the features above that fit you. It changes the conversation.
- Ask about referral. If you match the pattern, ask directly whether a rheumatology referral is appropriate. Rheumatologists, not general back pain services, diagnose AS.
- Ask about MRI. If X-rays were normal but symptoms fit, an MRI of the sacroiliac joints can show inflammation years earlier.
- Keep a record. Weeks of morning stiffness, night waking and how you respond to anti-inflammatories are exactly the details a rheumatologist looks for.
- Mention everything. Eye, skin, gut and heel problems can seem unrelated, but they're part of the picture.
A diagnosis matters. Treatment has improved a great deal, and earlier treatment gives a better chance of controlling inflammation before it causes lasting damage.
Build the record a rheumatologist looks for
Spondy logs morning stiffness, night pain, flares, medications and the BASDAI, and puts them into a report you can take to your GP or rheumatologist.
This article is for general information and isn't a substitute for medical advice. Talk to a doctor about your own symptoms, tests and treatment.