Ankylosing spondylitis is a chronic inflammatory rheumatic condition of the sacroiliac joints and the spine. The term used today is axial spondyloarthritis (axSpA) — “axial” because the axial skeleton is at the centre of it. In Germany the condition is still widely known by the eponym “Morbus Bechterew”.¹
The difference from wear and tear: the problem here is not degeneration but inflammation where tendons and ligaments insert into bone. The body repairs these sites with new bone tissue — over years, bony bridges can form between the vertebral bodies and stiffen the spine. That is why early treatment and exercise carry so much weight here.
Those affected are predominantly young people; the symptoms usually begin well before the age of 45. That is at the same time the central problem — with young adults who have back pain, hardly anyone thinks of an inflammatory rheumatic condition.
Normal or abnormal? You should take notice if the pain began insidiously, has lasted longer than three months, wakes you at night and improves with movement rather than getting worse. That combination is untypical of ordinary low back pain.
2. Forms of axial spondyloarthritis
The classification goes by the X-ray findings at the sacroiliac joints. That explains why a normal X-ray does not rule the condition out.¹
Radiographic axSpA (classic ankylosing spondylitis): structural changes are visible on the X-ray — they often only appear after years.
Non-radiographic axSpA: the symptoms are there, the X-ray is still normal; the inflammation often shows up on MRI. The burden is just as high, and the treatment follows the same principles.
Peripheral spondyloarthritis: here it is the joints of the arms and legs and the tendon insertions that are to the fore.
The family also includes forms that occur together with psoriasis or with inflammatory bowel disease. They share typical features: inflammatory back pain, pain at the tendon insertions and inflammation of the eye.
3. Inflammatory or mechanical back pain?
The most important feature distinguishing it from ordinary chronic back pain is the way the pain behaves: rest makes it worse, movement makes it better.¹,²
Feature
Inflammatory back pain
Mechanical back pain
Onset and duration
Insidious, before the age of 45, lasting longer than three months
Often sudden, at any age, usually episodic
At night
Typically wakes you in the second half of the night
Usually quiet at night
Morning stiffness
Pronounced, frequently over 30 minutes
Brief, eases quickly
Movement vs rest
Movement improves it, rest makes it worse
Movement often makes it worse, rest improves it
NSAIDs
Often a marked, rapid response
Variable
Table scrolls to the right
Other typical symptoms
Alternating buttock pain — deep-seated, sometimes on the right, sometimes on the left; an expression of the inflammation in the sacroiliac joints.
Pain at the tendon insertions (enthesitis) — often at the heel or the sole of the foot.
Peripheral joint pain — usually a few large joints, often asymmetrical; along with dactylitis, a swollen finger or toe.
Restricted mobility — rotation, bending to the side and the expansion of the chest on breathing all decrease.
Marked exhaustion — persistent tiredness is an underestimated accompanying complaint.
4. Causes: how to read HLA-B27
According to current knowledge the cause is not conclusively understood. An interplay of genetic predisposition and further factors is assumed.²
Genetic predisposition — the marker HLA-B27 is very often detectable in axial spondyloarthritis; cases among first-degree relatives also raise the risk.
A link with the bowel — in some of those affected, signs of inflammation are found in the bowel; inflammatory bowel disease occurs alongside it more often than by chance.
Smoking — unfavourable for the course and for the response to treatment.
HLA-B27 is not a test for the condition. The marker is also found in many healthy people — the vast majority of them never fall ill. A positive result proves nothing, and a negative one does not reliably rule the condition out. The test only makes sense where the symptoms fit.
The medicines angle. Medicines do not cause axial spondyloarthritis, but they can blur the picture: taking painkillers regularly over months dampens precisely that night-time pain pattern which provides the decisive clue. So make a note of when and how often you need them.
5. Diagnosis: why it often takes years
Several years often pass between the first symptoms and the diagnosis. The reasons: back pain is extremely common, those affected are young, the X-ray is normal at first, and movement improves the symptoms — which is falsely reassuring.²,³
History and examination: the character of the pain, night pain, morning stiffness, heel pain, inflammation of the eye, bowel symptoms, rheumatic conditions in the family; plus mobility of the spine, chest expansion and tests of the sacroiliac joints.
Laboratory tests: CRP and the ESR can be raised, but are often normal — that does not rule the condition out.
X-ray and MRI: a pelvic X-ray only shows structural changes late; MRI makes active inflammation visible early — decisive for an early diagnosis.
Referral to rheumatology: recommended for chronic back pain starting before the age of 45 together with at least one further pointer — an inflammatory pain pattern, a good response to NSAIDs, inflammation of the eye or a positive HLA-B27.
What has to be told apart from it is ordinary low back pain, a herniated disc and wear and tear. The difference rarely lies in the image; most often it lies in the story.
6. Treatment: exercise as the foundation
In hardly any other rheumatic condition is non-drug treatment so clearly on a par with the medicines. Regular exercise and physiotherapy are part of the treatment according to the guideline — not as a nice extra but as the basis: they maintain mobility, ease stiffness and work against the stiffening.¹
FoundationNot negotiable, and for life
A daily exercise programme
Stretching and extension of the spine, rotation, breathing exercises, strengthening of the trunk muscles. Short and daily beats long and rare — ten to fifteen minutes in the morning break the stiffness most effectively.
Supervised exercises help you spot poor posture early — Funktionstraining is the group exercise therapy that can be prescribed in Germany and is usually covered by statutory health insurance. Smoking is unfavourable for the course, for mobility and for the response to treatment.
First lineMedicines: NSAIDs
Non-steroidal anti-inflammatory drugs
First choice for inflammatory back pain. Where the condition stays persistently active, regular rather than as-needed use is considered; the dose is set by your practice.
Second lineWhen NSAIDs are not enough
Biologics (TNF inhibitors, IL-17 inhibitors)
These come into consideration where the condition stays active despite an adequate trial of NSAIDs. They intervene in specific messengers of the inflammation and can reduce pain and stiffness considerably. JAK inhibitors are a further option.
What expressly does not help here. Steroid tablets have no established place in the purely axial form — unlike in many other rheumatic conditions. Classic disease-modifying drugs also generally have no effect on the involvement of the spine; local injections remain reserved for individual inflamed joints.
7. Medicines: NSAIDs and biologics
NSAIDs: more than just painkillers
In axial spondyloarthritis, non-steroidal anti-inflammatory drugs hold a special position: they not only ease the pain, they dampen the inflammation itself. A prompt, marked response even counts as a diagnostic pointer. Among those used are ibuprofen and naproxen; the latter lasts longer and is often preferred for night pain, because an evening dose can cover the second half of the night.¹,⁴
Long-term use needs monitoring. Where NSAIDs are taken regularly over a longer period, the risks of gastrointestinal bleeding, of a rise in blood pressure and of a deterioration in kidney function all go up — particularly together with blood pressure medicines, water tablets or blood thinners. Where risk factors are present, stomach protection such as pantoprazole is often added; pointers are given in the guide Stomach problems from medications. Do raise kidney and blood pressure checks actively.
Biologics: targeted against the messengers of inflammation
If the condition stays active despite consistent exercise therapy and an adequate trial of NSAIDs, biologics are the next step. Two classes of medicine are to the fore:
TNF-alpha inhibitors
These block the messenger tumour necrosis factor alpha, have been in use here the longest and are given as an injection under the skin or as an infusion.
Interleukin-17 inhibitors
An alternative where TNF inhibitors do not work well enough or are not an option — also effective where psoriasis occurs alongside.
Infection risk and vaccination status. Biologics dampen specific parts of the immune system — infections can occur more often and run more severely. Before treatment starts, tests are done for an unnoticed tuberculosis and for hepatitis, among other things. Vaccination cover should be brought up to date beforehand, because live vaccines are generally not possible while treatment is running. With a fever, feeling severely unwell or breathlessness, medical advice should be sought promptly.
Classic disease-modifying drugs
Substances such as methotrexate or sulfasalazine have no convincing effect on the involvement of the spine on current evidence; they can be useful where there is additional inflammation in the joints of the arms and legs. That is an important difference from other forms of inflammatory rheumatic disease, in which these medicines form the backbone of treatment.
How often do you really need that NSAID?
brite shows you how often you take it, your night pain pattern and your breaks at a glance.
Axial spondyloarthritis rarely stays confined to the back. These accompanying conditions are so common that they are asked about specifically.⁴
A red, painful eye: see an eye specialist promptly. Inflammation of the iris (acute anterior uveitis) is the most common accompanying condition outside the musculoskeletal system. Typical are a suddenly red, painful eye, sensitivity to light and blurred vision, usually on one side. It responds well to treatment, but left untreated it can put your sight at risk: go to an eye practice the same day and mention your spondyloarthritis.
Inflammatory bowel disease:Crohn's disease and ulcerative colitis occur alongside it more often than by chance. Persistent diarrhoea, blood in the stool or weight loss need assessing — they also influence the choice of medicine.
Osteoporosis: chronic inflammation and restricted mobility raise the risk of bone loss — sometimes already at a young age and despite the apparently “stable” stiffened spine. More in the article on osteoporosis.
Cardiovascular risk: raised, as in other chronic inflammatory conditions — blood pressure, blood lipids and stopping smoking are part of the treatment.
A stiffened spine raises the risk of fracture. A spine that has fused over years is more rigid and at the same time more brittle; even seemingly harmless falls can lead to vertebral fractures. New back pain that has changed markedly after a fall — all the more so with numbness, loss of strength or problems passing urine — belongs in the emergency department without delay.
9. Course and outlook
The outlook calls for honesty in both directions. It is true that axial spondyloarthritis is chronic and, according to current knowledge, cannot be cured. It is equally true that the picture of a completely fused, forward-bent spine is not the typical course. It comes from a time when the condition was recognised late and could hardly be treated effectively.³
The course varies a great deal: some people have only mild symptoms over years, others struggle with high disease activity. Persistently high inflammatory markers, structural changes visible early and smoking all work against you; an early diagnosis, daily exercise and consistent treatment work in your favour. A relevant part of the outlook therefore lies in areas you can influence.
10. Everyday life with ankylosing spondylitis
A morning routine rather than a weekend programme — ten to fifteen minutes of stretching straight after getting up work against morning stiffness more reliably than one long session a week.
Choose your sport rather than dropping it — swimming, Nordic walking and training focused on extension are regarded as favourable; a strongly bent posture or a high risk of falling rather less so. Pointers are given in the guide Medications and exercise.
Straighten up your workstation — screen at eye level, frequent changes of position, short movement breaks. Sitting for long stretches in a bent posture is particularly unfavourable here.
Sleep flat and firm — a medium-firm mattress and a flat pillow. Many people find warmth before their morning exercises helpful; the evidence for this is limited.
Document your symptoms — night pain, how long the stiffness lasts in the morning, how much painkiller you need. Those three pieces of information often say more about disease activity than any single laboratory value. The guide Prepare for a doctor's appointment helps you get ready.
If several products come together over time — an NSAID, stomach protection, a biologic — it is worth a systematic look at possible interactions.
Document night pain, stiffness and medicines
Your course over months — cleanly prepared for your next rheumatology appointment.
FAQ: Common questions about ankylosing spondylitis
Typical is an insidious onset before the age of 45, a duration of more than three months, night pain in the second half of the night and pronounced morning stiffness. The most important feature: movement improves the symptoms and rest makes them worse — with mechanical back pain it is the other way round.
No. HLA-B27 is a widespread inherited factor, and the vast majority of people who carry it never fall ill. It only raises the probability and is one building block in the overall picture. Conversely, a negative result does not reliably rule the condition out.
Yes. Structural changes on the X-ray frequently only develop after years; during that time it is called non-radiographic axial spondyloarthritis. Active inflammation can often be shown on MRI of the sacroiliac joints. Inflammatory markers in the blood can be normal too.
No. Only some of those affected develop a complete fusion, and that over many years. The picture of the strongly bent spine comes from a time without early diagnosis and effective treatment. Early treatment, daily exercise and stopping smoking all influence the course favourably.
Because in this condition they are part of the treatment and not merely an addition. Regular exercises maintain mobility and chest expansion, ease stiffness and work against poor posture. Short daily sessions are more effective than rare long ones.
That depends on disease activity. Where the condition stays persistently active, regular use is considered; where the course is quiet, as-needed use. Long-term treatment requires checks on blood pressure, kidney function and how well your stomach tolerates it. The decision is taken by the practice treating you together with you.
A suddenly red, painful eye with sensitivity to light and blurred vision can be inflammation of the iris — the most common accompanying condition of axial spondyloarthritis. It responds well to treatment, but left untreated it can put your sight at risk. Go to an eye practice the same day.
German S3 guideline on axial spondyloarthritis including ankylosing spondylitis and early forms (DGRh, AWMF reg. no. 060-003) — German source. awmf.org
gesundheitsinformation.de, German Institute for Quality and Efficiency in Health Care (IQWiG): Ankylosing spondylitis — German source. Accessed 2026. gesundheitsinformation.de
gesund.bund.de, the national health portal of the Federal Ministry of Health: Ankylosing spondylitis — German source. Accessed 2026. gesund.bund.de
Medical disclaimer: This article is for general information and does not replace medical advice, diagnosis or treatment. A suddenly red, painful eye needs an eye examination the same day; after a fall with changed back pain, numbness, loss of strength or problems passing urine, the emergency department is the right place — if there are emergency signs, call the emergency services on 112 (in Germany). Do not take anti-inflammatory painkillers long term on your own initiative. The choice of medicine and the dose are always determined individually by the practice treating you. Last updated: August 2026.
