Ankylosing Spondylitis (AS) and other Spondyloarthritis Diseases

Symptoms, diagnosis, treatments, and resources for patients and others about Ankylosing Spondylitis and other Spondylitis disorders.

We shine this Spotlight on Ankylosing Spondylitis (AS). It is sometimes classified as Radiographic Spondyloarthritis (rSpA), because the typical bone damage or fusion is visible on X-rays. Ankylosing Spondylitis is the most prevalent of several types of chronic Spondyloarthritis diseases. These typically produce joint (especially lower back) pain, morning stiffness, fatigue as well as other chronic and fluctuating symptoms. Unfortunately, long-term untreated disease may lead to spinal fusion and permanent deformity, so diagnosis and treatment are essential. Below, are basic facts about this autoinflammatory arthritis that primarily affects the lower spine. Further down, links will connect you to available statistics, research initiatives, supportive patient communities and more!

Is AS the oldest autoinflammatory disease?

Smilodon fossil sabertooth cats suffered from ankylosing spondylitis
A fossil Saber-toothed cat: Smilodon fatalis
By stu_spivack – ? model skeletonUploaded by FunkMonk, CC BY-SA 2.0,

Ankylosing Spondylitis has the dubious distinction of being the oldest autoinflammatory disease we know of. That’s because spinal, especially sacroiliac, fusion may be preserved in bones or fossils. There are even dinosaur fossils with typical hip and lumbar lesions! Typical AS lesions are also found in fossil bones of cave bears and saber-toothed cats. Some of the Smilodon specimens from the La Brea Tar Pits show sacroiliac AS.

Thus, it’s not surprising that human AS has been around a long time, too. The oldest specimen is an Egyptian man from the third Dynasty period (~2900 BCE). Additional burials from Europe, Africa and South America dating from 400 BCE to 500 AD show skeletal changes diagnostic of AS.

Historically, however, the disease was first described by a physician in 1691. AS was repeatedly spotted throughout the 19thC. By 1904 Frankel named it “spondylitis ankylopoietica.” This disease has gone through many different names and classifications over the decades. Even today, definitions and classification of spondylitis are in flux.

Today, an emerging consensus is that AS is a chronic autoinflammatory disease. That is, AS is a result of an overactive innate immune system. This is in contrast to autoimmune diseases that involve dysfunction of the adaptive immune system.

An Overview of the Spondylitis disorders

Ankylosing Spondylitis is a chronic rheumatic and a systemic autoinflammatory disease. It is the most prevalent of a family of inflammatory spinal arthritis disorders. Rheumatologists call them the spondyloarthritides or Spondylitis, which translates to “inflamed vertebral joints”. Nevertheless, these diseases may also produce non-spinal symptoms and may co-occur with autoimmune diseases. The common element is that the innate immune system, the first line of defense against infectious pathogens, attacks its own joint tissues, causing chronic inflammation, pain and progressive damage. These are distinct from autoimmune diseases, in which the adaptive immune system is the dysfunctional culprit, but they have similar symptoms and patients may have both disorders. Rheumatoid Arthritis (RA) is the classic rheumatic autoimmune arthritis.

There are several additional diseases in this category. One is Psoriatic Arthritis (PsA) (associated with the autoimmune skin disease, Psoriasis). Another is Enteropathic Arthritis (EA) (associated with Inflammatory Bowel Disease–IBD: Crohn’s disease and Ulcerative Colitis). Recently, a newer classification system groups these diseases as axial (central, as in the spine) or peripheral (outside the spine). Or, as shown below, arthritis classifications can divide them into inflammatory and non-inflammatory causes. The seropositive branch includes autoimmune diseases (disorders of the adaptive immune system) with joint symptoms. The seronegative branch is a group of autoinflammatory arthritides, disorders of the innate immune system. This spotlight shines on the seronegative spondyloarthritis diseases.

Ankylosing Spondylitis overview

the pelvic girdle showing sacrum, ilia and sacroiliac joints
The pelvic girdle, showing the ilia, sacrum and their connection, the sacroiliac joints.

Typically, the AS disease process starts before age 40 and is focused on the lower (lumbar) vertebrae. Specifically, the hallmark of AS is chronic pain and stiffness after rest in the sacroiliac joints (sacroilitis). The sacroiliac joint connects the terminal vertebrae, the sacrum (the flat triangular bone in the back of the pelvis), to the pelvic bones (ilia).

Over time, chronically inflamed connective tissue (entheses) in the spine leads to scarring and eventually formation of extra bone. If allowed to persist, it can cause fusing of the sacroiliac joint and the spine. Eventually this can lead to reduced flexibility and a hunched posture. Ankylosing Spondylitis can affect other joints too, including hips, ribs, shoulders, even smaller joints in the hands and feet. Sometimes AS causes eye inflammation: uveitis (inflamed white part of the eye) or iritis (inflamed iris). Rarely, the disease may inflame and damage heart and lung tissue.

Ankylosing Spondylitis Statistics

Current available ankylosing spondylitis statistics estimate that…

  • An estimated 1 in 2,000 people suffer from AS.
  • Symptoms most commonly emerge in young adults.
  • Men are affected 7 times more than women.
  • Genetic marker HLA-B27 may predispose people to spondylitis.

Symptoms of Ankylosing Spondylitis

Symptoms include chronic low back pain, sometimes severe, back and hip stiffness (especially in the morning after sleep), reduced mobility and fatigue. Hip, rib, chest, shoulder, heel, even wrist pain are not unusual. This is because, as a systemic condition, AS can affect many parts of the body. In some patients, eye inflammation symptoms include eye pain, blurred vision and light sensitivity. Moreover, there may even be gut or skin symptoms, which suggest a diagnosis of EA or PsA. As with most immunological diseases, the course is variable from person to person and within individual patients. For example, symptom flares and periods of remission are typical. Flare triggers include food sensitivities, stress, and lack of exercise.

Diagnosis of Ankylosing Spondylitis

Patients generally experience low back pain and stiffness after rest, which prompts them to see their primary care physician (PCP). This post has helpful advice for preparing for a doctor visit. The diagnosis pathway begins with a physical exam by your PCP. Your doctor will test the range of motion of your spine. If limited mobility and other symptoms suggest a rheumatological disease, your PCP will then refer you to a rheumatologist. Your PCP or rheumatologist may give you an assessment tool to fill out. These include questions about pain, mobility and your ability to do work and play activities. Once you are in treatment, you and your doctor may use these tools to monitor disease progress or remission.

Since there is no one test for Ankylosing Spondylitis or the other spondyloarthritis disorders, diagnosis is based on family and personal history, blood labs and imaging. A family history of inflammatory low back pain is suggestive. So is having biological family members with autoimmune diseases, especially Psoriasis, PsA or IBD. More importantly, an even bigger clue is a personal history of inflammatory sacroiliitis.

A genetic marker, HLA-B27, can be detected on DNA testing. However, HLA-B27 positive results are not definitive. Some 90% of white European AS patients will be positive, but the allele is less common among people of other ethnicities. Furthermore, most HLA-B27 positive people never develop Ankylosing Spondylitis. Other blood tests include Erythrocyte Sedimentation Rate (ESR) and C-reactive protein (CRP), levels of which are elevated in many, but not every, AS case. Finally, radiology can show gross changes in joints and bones (Radiographic Spondyloarthritis). However, if X-rays are negative (Nonradiographic Spondyloarthritis), MRIs can show more detailed images of the affected parts of the spine.

Treatment & Management of AS

Unfortunately, there is no cure for AS. Therefore, treatment aims to relieve symptoms and prevent further complications. In the first place, consistent regular exercise is essential to maintain mobility and prevent deformity. Active physical therapy can help with flexibility in the spine and overall posture. Other movement therapies may help, too.

However, medications may be necessary to treat pain and stiffness. Firstly, nonsteroidal anti-inflammatory drugs (NSAIDs) can relieve inflammation and thus pain and stiffness. The preferred specialty medicines (biologics) are tumor necrosis factor (TNF) blockers that can relieve swollen or tender joints. Sometimes, steroid injections are used. Moreover, a variety of alternative, complementary, or functional treatments may be integrated with conventional treatment. These include massage (although it may be a trigger in some patients), acupuncture and yoga.

Certain foods and food components may help manage AS symptoms. Additionally, some patients may have food sensitivities as well. This is especially likely in people with gut symptoms or an IBD diagnosis. The gut microbiome may be a mediator of these effects. In any case, check out our YAC Food Spotlight on Ankylosing Spondylitis.

In conclusion

While the Spondylitis Association of America and other organizations raise awareness and improve care, our team at Your Autoimmunity Connection connects patients with one another and with available resources.

Educational resources

Brush up on the basics

While some of you may already have some background about Ankylosing Spondylitis, let’s review the basics. The following pages provide a comprehensive overview of AS:

Find patient communities

Research & clinical trials

The Spondylitides are chronic inflammatory conditions

Finally, let us remember that the Spondylitides, including AS, are chronic autoinflammatory conditions. Along with autoimmune diseases, there are more than 100 individual diagnoses. According to our research, some 24-50 million Americans suffer from one or more autoimmune diseases. Furthermore, a research study estimated that approximately 25% of patients with one autoimmune diagnosis develop additional autoimmune diseases.¹

All in all, we hope our Spotlight on
Ankylosing Spondylitis connects you with useful resources and information. Moreover, we believe it is essential to take a holistic approach to combat the autoimmune disease epidemic. Thus, by focusing on chronic inflammatory diseases together, we can see the total size of this invisible epidemic. Therefore, we promote concerted action to reshape research, diagnosis, and treatment. In particular, our model is the revolution in cancer research and treatment over the past 50 years. That revolution was only made possible by viewing cancer as a group of diseases with a common foundation. As a single category, cancer has garnered far more resources than were devoted to individual cancers alone.

Nonetheless, help us bring this revolution to autoimmune, autoinflammatory and all chronic inflammatory disorders!
Contact us if you want to help.

Written by: Bonnie Feldman, DDS, MBA, Anna Simon, Ellen M. Martin

Why autoimmune and autoinflammatory disease?

Autoimmune disease is an “invisible epidemic”. Despite affecting roughly 16% of the US population (as many people as cancer), chronic inflammatory diseases remain under-recognized, under-researched and under-served. Therefore, to raise awareness and connect patients, families and caregivers with useful resources, Your Autoimmunity Connection publishes a series of “Spotlights” on autoimmune diseases.

Chronic inflammatory diseases are high-beta, high-risk and high-cost to payers and providers, especially for employer-sponsored health care benefits programs. Therefore, these spotlights also offer useful background for benefits managers and digital entrepreneurs building companies and products addressing these diseases.

Get acquainted with Your Autoimmunity Connection

  • Check out our blog at for all things autoimmune. These include updates in research, lifestyle modifications, patient stories, and more.
  • Find us on Facebook here, or join our Facebook Forum to connect with patients across all autoimmune diseases.
  • Read our Guide to Food Therapy
  • Check out our other disease Spotlights here

[1] Cojocaru, M, Inimioara Mihaela Cojocaru, and Isabela Silosi. “Multiple Autoimmune Syndrome.” Mædica 5.2 (2010): 132–134. Print.


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