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Roughly 80 percent of lower limb amputations in the United States happen because of complications from diabetes. Most of them trace back to the
Medically Reviewed by
Dr. Yelliann Ruiz Irizary, MD
Board Certified Rheumatologist
When most people picture arthritis, they think of aching knees or swollen finger joints, not a dull ache in the lower back that shows up in someone’s twenties or thirties. That gap in perception is part of why ankylosing spondylitis is one of the most overlooked forms of arthritis. It is often mistaken for a strained muscle, a mattress problem, or simply the price of a desk job, and years can pass before someone gets an accurate diagnosis. Below, we walk through the symptoms of ankylosing spondylitis, how they tend to progress, who is most at risk, and when it makes sense to see a rheumatologist for an evaluation.
Ankylosing spondylitis, sometimes called axial spondyloarthritis, is a chronic inflammatory condition that mainly targets the spine and the sacroiliac joints, where the base of the spine meets the pelvis. Over time, the ongoing inflammation can prompt the body to form new bone in an effort to heal itself, and that new bone can bridge the gaps between vertebrae.
When enough of these bridges form, sections of the spine can fuse together, which reduces flexibility and can lead to a stooped or hunched posture. Ankylosing spondylitis is considered an autoimmune condition, meaning the immune system mistakenly attacks healthy joint tissue rather than protecting it.
There is currently no cure for ankylosing spondylitis, but that does not mean it is untreatable. With an accurate diagnosis and a consistent treatment plan, many people manage their symptoms effectively and continue with active, productive lives for decades.
Ankylosing spondylitis is frequently missed in its early stages because the first symptom, lower back pain, is so common in the general population that it rarely raises alarm. Most back pain is mechanical, meaning it comes from muscle strain, poor posture, or an injury, and it tends to improve with rest.
Ankylosing spondylitis works in reverse. The pain is inflammatory rather than mechanical, so it typically improves with movement and worsens with rest, which is the opposite of what most people expect from a back problem. Because the condition can also mimic seronegative rheumatoid arthritis and other forms of inflammatory arthritis in its early presentation, it is sometimes misclassified before a rheumatologist narrows down the correct diagnosis.
On average, people with ankylosing spondylitis can wait several years between their first symptoms and a confirmed diagnosis. Recognizing the specific pattern of symptoms described below is often the fastest path to getting the right specialist involved sooner.
It also helps to understand how ankylosing spondylitis differs from more widely known forms of inflammatory arthritis. Our page on rheumatoid arthritis outlines how that condition typically presents in the hands and other small joints, which is a useful point of comparison when trying to sort out an unfamiliar set of symptoms.
The hallmark early symptom of ankylosing spondylitis is a dull, diffuse ache in the lower back and buttocks that develops gradually over several weeks or months, rather than appearing suddenly after an injury. In the beginning, the discomfort may only affect one side of the body, or it may alternate between sides.
This is different from the back pain that most adults experience at some point from muscle strain or disc issues. Inflammatory back pain associated with ankylosing spondylitis tends to be persistent, lasting more than three months, and it typically becomes symmetrical, affecting both sides of the lower back as it progresses.
A useful clue for anyone trying to distinguish the two is timing. Mechanical back pain usually feels worse after activity and better with rest. Ankylosing spondylitis pain tends to do the opposite, easing with light movement or a warm shower and returning after long periods of sitting or lying still.
Left unaddressed, the stiffness and discomfort of ankylosing spondylitis do not usually stay confined to the lower back. Over months or years, the inflammation can spread upward along the spine and into the neck, and it can also radiate into the ribs, shoulder blades, hips, thighs, and heels.
Symptoms rarely follow a straight, steady line. Many people describe a pattern of flares, when pain and stiffness intensify, followed by periods of remission when symptoms ease or nearly disappear. This unpredictable rhythm is part of why the condition can be so easy to dismiss early on, since a person might feel fine for weeks at a time between flares.
Without treatment, chronic inflammation can eventually lead the body to build new bone around the affected joints, which is the process that causes vertebrae to fuse. This is why catching the condition earlier, before significant fusion occurs, generally allows for more treatment options and better long-term mobility.
A defining feature of ankylosing spondylitis is that symptoms are usually at their worst first thing in the morning or after any extended period of inactivity. Many people wake up feeling stiff through the lower back and hips, and that stiffness can take thirty minutes or longer to loosen up.
Nighttime pain is another common pattern. Because the condition is aggravated by stillness, some people are woken from sleep in the second half of the night by back or hip discomfort, even though they were not in pain when they went to bed.
Both symptoms tend to respond to movement. A warm shower, gentle stretching, or a short walk in the morning often brings noticeable relief, which is one more piece of evidence pointing toward an inflammatory rather than a mechanical cause.
Fatigue is one of the most common, and most frequently overlooked, symptoms of ankylosing spondylitis. Ongoing inflammation takes a real physical toll, and the body expends a significant amount of energy managing it, which can leave people feeling drained even on days when their pain is relatively mild.
Mild to moderate anemia related to chronic inflammation can also contribute to this tiredness. Because fatigue is such a broad, nonspecific complaint, it is easy for both patients and providers to attribute it to stress, poor sleep, or a busy schedule rather than an underlying inflammatory condition.
When persistent fatigue shows up alongside morning stiffness and back pain that improves with activity, it strengthens the case for asking a healthcare provider about ankylosing spondylitis specifically, rather than treating fatigue as an isolated issue.
While the spine and sacroiliac joints are usually where ankylosing spondylitis begins, the condition can also affect peripheral joints such as the hips, knees, ankles, shoulders, and heels. This is somewhat more common in children and younger people with the condition.
A related source of pain is enthesitis, which is inflammation where a tendon or ligament attaches to bone. This commonly shows up as heel pain, particularly at the Achilles tendon or the bottom of the foot, and can be mistaken for a simple case of plantar fasciitis rather than a sign of systemic inflammation.
If the joints connecting the ribs to the spine and breastbone become involved, some people notice it becomes harder to take a full, deep breath. This symptom is less common than back pain, but it is a useful signal that should prompt a medical evaluation rather than being brushed aside.
Ankylosing spondylitis is not limited to the joints. About one in three people with the condition will experience uveitis, sometimes called iritis, which is inflammation inside the eye, at least once during the course of their illness.
The warning signs of uveitis include a red, painful, and watery eye, sensitivity to bright light, and blurred vision, usually affecting one eye at a time. Unlike joint symptoms, which tend to build gradually, uveitis can come on relatively quickly.
Because untreated uveitis can threaten vision, it is considered a symptom that warrants prompt attention. Anyone with a known diagnosis of ankylosing spondylitis who develops sudden eye pain or vision changes should be seen by an eye specialist right away, rather than waiting to see if it resolves on its own.
Ankylosing spondylitis belongs to a broader family of conditions known as spondyloarthritis, which helps explain why it often overlaps with digestive and skin issues. Some people with ankylosing spondylitis also develop inflammatory bowel disease, such as Crohn’s disease or ulcerative colitis, which can cause abdominal pain and changes in bowel habits.
Psoriasis, a chronic skin condition marked by red, scaly patches, is another condition that shows up more often in people with ankylosing spondylitis. The relationship runs in both directions, since psoriasis is also linked to psoriatic arthritis, a separate but related form of inflammatory arthritis. Our guide on psoriatic arthritis versus psoriasis breaks down how these two conditions differ.
Because these symptoms can appear years apart, and often get treated by different specialists working independently, they are not always connected back to a single underlying inflammatory process. Sharing your full symptom history, even details that seem unrelated to back pain, helps a rheumatologist see the full picture.
Ankylosing spondylitis has historically been viewed as a condition that mostly affects men, and it is still diagnosed more often in men than women. That has contributed to a pattern where women can present with somewhat different, or more atypical, symptoms, which can make the diagnosis take even longer.
Some women report that their symptoms started in the neck rather than the lower back, or that peripheral joint pain in the hips or knees appeared earlier and more prominently than classic low back symptoms. Fatigue and widespread discomfort may also be more pronounced in some cases.
Because these presentations do not always match the textbook description of the condition, women with unexplained, persistent joint pain and stiffness may need to be more assertive about requesting a rheumatology referral, especially if initial evaluations do not turn up a clear explanation.
Ankylosing spondylitis most often begins between the ages of seventeen and forty five, though it can occasionally appear in children or later in adulthood. A family history of the condition raises the likelihood of developing it, since genetics play a meaningful role.
The gene most closely associated with ankylosing spondylitis is HLA-B27. Having this gene increases risk substantially, but it does not guarantee that someone will develop the condition, and plenty of people with ankylosing spondylitis do not carry the gene at all, which tells researchers that environmental factors matter too.
People who already have Crohn’s disease, ulcerative colitis, or psoriasis appear to be somewhat more likely to develop ankylosing spondylitis as well. None of these risk factors are within a person’s control, which is one more reason why recognizing symptoms early matters more than trying to prevent the condition outright.
There is no single test that confirms ankylosing spondylitis on its own. A rheumatologist typically starts with a detailed conversation about symptom patterns, including when pain started, what makes it better or worse, and whether it runs in the family.
From there, imaging plays a central role. X-rays of the pelvis and spine can reveal changes in the sacroiliac joints, while an MRI can sometimes detect inflammation even before it becomes visible on an X-ray. Blood tests may be used to check for the HLA-B27 gene and to look for general markers of inflammation, though these results are interpreted alongside the clinical picture rather than in isolation.
Because inflammatory back pain can resemble other forms of arthritis in its early stages, a rheumatologist will often rule out other possibilities along the way. Our comparison of osteoarthritis versus rheumatoid arthritis is a helpful starting point for understanding how these more familiar conditions differ from an inflammatory spine disease like ankylosing spondylitis.
When ankylosing spondylitis goes unmanaged for years, the ongoing inflammation and new bone formation can lead to significant fusion of the vertebrae, resulting in a rigid, inflexible spine and a hunched posture that is difficult to reverse. Fused, weakened vertebrae are also more prone to compression fractures, which can in some cases affect the spinal cord or nearby nerves.
If the joints connecting the ribs become involved, chest expansion can become limited enough to affect breathing capacity over time. Ankylosing spondylitis has also been linked to inflammation of the aorta, the body’s largest artery, which in rare cases can affect how well the heart’s valves function.
These outcomes are far from inevitable. They represent what can happen in longstanding, poorly controlled disease, which is precisely why an earlier diagnosis and a consistent treatment plan make such a meaningful difference in long-term outlook.
While ankylosing spondylitis cannot currently be cured, a combination of approaches can meaningfully reduce pain, preserve mobility, and slow disease progression. Regular exercise and physical therapy are often the foundation of treatment, since staying active helps maintain flexibility and posture in ways that rest alone cannot.
Medication options range from over the counter anti-inflammatory drugs for milder symptoms to prescription biologic medications and other targeted therapies for people with more persistent or severe disease. These medications work by calming the immune response that drives the inflammation in the first place, rather than only masking pain.
Surgery is reserved for a small minority of cases involving severe joint damage or significant spinal deformity, and it is generally considered only after other treatments have been tried. Most people are able to manage ankylosing spondylitis successfully without ever needing a surgical procedure.
It is worth scheduling an evaluation with a rheumatologist if you have lower back or buttock pain that developed gradually, has lasted more than a few months, feels worse in the morning or after rest, and improves with movement. This pattern, especially in someone under forty five, is different enough from ordinary back strain to warrant a closer look.
The same is true if back pain is accompanied by other symptoms discussed above, such as unexplained fatigue, heel pain, eye redness or light sensitivity, or a family history of ankylosing spondylitis or related autoimmune conditions. Our overview of when to see a rheumatologist covers additional signs that point toward a rheumatology referral.
While waiting for an appointment, gentle stretching, staying as active as pain allows, applying heat to stiff areas, and maintaining good posture can all help make symptoms more manageable in the short term. These measures are not a substitute for a diagnosis, but they can ease day to day discomfort while you pursue an accurate answer.
Not exactly. Ankylosing spondylitis is a specific type of inflammatory arthritis that mainly affects the spine and sacroiliac joints, rather than the more familiar wear and tear arthritis, called osteoarthritis, that develops in joints like the knees and hips with age.
There is currently no cure for ankylosing spondylitis. However, a combination of exercise, physical therapy, and medication can control symptoms, slow progression, and allow most people to remain active and independent.
Symptoms most commonly begin between the ages of seventeen and forty five, with many people first noticing back pain and stiffness in their twenties or thirties. It can occasionally develop in children or appear later in life.
Ankylosing spondylitis pain tends to develop gradually, last more than three months, feel worse with rest and better with movement, and often shows up alongside morning stiffness, fatigue, or symptoms in other parts of the body. Ordinary back strain typically improves with rest and resolves within a few weeks.
No. Having the HLA-B27 gene increases the risk of developing ankylosing spondylitis, but many people who carry the gene never develop the condition, and some people with ankylosing spondylitis do not have the gene at all.
A rheumatologist, a physician who specializes in arthritis and autoimmune conditions, typically diagnoses and manages ankylosing spondylitis, often working alongside physical therapists and, in some cases, eye specialists or gastroenterologists depending on which symptoms are present.
Ankylosing spondylitis, Symptoms and causes
Ankylosing Spondylitis, NIAMS
Ankylosing Spondylitis, Cleveland Clinic
Ankylosing Spondylitis Symptoms, Spondylitis Association of America
Dr. Yelliann Ruiz Irizarry is a board-certified rheumatologist and internist, fellowship-trained at the University of Miami/Jackson Health System, with extensive experience in treating complex autoimmune and joint conditions. She serves as Director of Rheumatology and Joints at South Florida Multispecialty Medical Group, specializing in rheumatoid arthritis, lupus, gout, osteoporosis, and joint pain management.
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