Axial spondyloarthritis (axSpA) and rheumatoid arthritis (RA) are autoimmune diseases in which the body malfunctions and attacks healthy tissues. They are also both types of inflammatory arthritis, conditions that cause joint inflammation.
In axSpA, the immune system attacks the small bones of the spine called the vertebrae and the joints between the pelvic bones and the base of the spine. In RA, the immune system attacks the synovium (the lining of the joints).
AxSpA and RA are systemic conditions; they can affect the entire body. They share some things in common, but they also have many differences. This article will cover the similarities and differences between axial spondylitis and rheumatoid arthritis, including symptoms, causes, treatment, and more.
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Symptoms
Axial spondyloarthritis belongs to a family of inflammatory conditions called spondyloarthritis, or spondyloarthropathy, primarily affecting the axial joints (the spine, chest, and pelvis). These conditions might also affect the peripheral joints of the arms and legs and other body systems.
Both subtypes of axSpA—ankylosing spondylitis (AS) and non-radiographic axSpA (nr-axSpA)—cause inflammation of the spine and sacroiliac (SI) joints linking the pelvis to the spine.
Nr-axSpA causes inflammation of the spine and SI joints, but there is no radiographic damage (damage that can be seen on X-rays). AS, on the other hand, is progressive and will eventually lead to joint damage. Nr-axSpA is sometimes a precursor to AS.
Rheumatoid arthritis causes joint inflammation and pain throughout the body. It commonly occurs in the hands, knees, or ankles, but any joint can be affected.
RA is symmetrical, meaning it affects the same joints on both sides of the body, such as both hands or both feet. When RA progresses, it can cause damage to joints and lead to problems in other parts of the body, including the eyes, heart, lungs, and circulatory system.
Both axSpA and RA are characterized by flare-ups and periods of remission. Flare-ups are times when the condition causes significant symptoms. Remission means little or no disease symptoms.
Rheumatoid Arthritis
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Fatigue
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Malaise
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Joint pain
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Muscle aches
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Eye inflammation
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Rheumatoid Nodules
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Loss of Appetite
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Low-grade fever
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Morning stiffness
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Anemia
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Neck pain
Axial Spondyloarthritis
AxSpA affects up to 1.4% of people in the United States, according to a 2020 report. Nr-axSPA is equally prevalent among people of any sex. Historically, AS was noted to be 2 to 3 times more prevalent in males than in females. However, a 2018 paper notes only a slight difference in male-to-female AS prevalence of 1.03-to-1.
Terminology
Verywell Health prefers to use inclusive terminology. But when citing research or authoritative sources, the terms relating to sex or gender from those sources will be used.
Most people receive an AS or nr-axSpA diagnosis before age 45, but these axSpA subtypes most often start between ages 20 and 40. They can also affect teens and young children.
The main symptom of axSpA is inflammatory back pain due to inflammation of the joints of the spine. Inflammatory back pain differs from mechanical back pain, which often results from muscle strains or disc problems.
According to the Spondylitis Association of America, inflammatory back pain has unique features that help distinguish it from mechanical back pain.
Such features include:
- Chronic back pain in someone under age 35
- Back pain lasting three or more months
- Back pain and stiffness that worsens with inactivity and is worse at night and early in the morning.
- Back pain and stiffness that improves with physical activity and nonsteroidal anti-inflammatory drugs (NSAIDs)
Additional symptoms axSpA might cause are:
- Buttock and hip pain
- Neck pain
- Fatigue
- Eye inflammation
- Psoriasis (an autoimmune skin disease that causes patches of thick red skin covered with silvery scales)
- Inflammatory bowel disease (inflammation of the lining of the digestive tract)
- Peripheral arthritis
- Enthesitis (inflammation in the places where ligaments and tendons connect to bone, like the Achilles heel of the foot)
Rheumatoid Arthritis
According to the American College of Rheumatology, RA is the most common autoimmune disease, affecting up to 1.3 million Americans. About 75% of people with RA are assigned female at birth. It is most often diagnosed between ages 30 and 50 but can start at any age.
RA causes inflammation of the joint lining leading to pain, stiffness, and swelling of the joints. It commonly affects the small joints of the hands and feet. RA might also affect the organs, most often the eyes and skin.
Joint stiffness from RA is the worst in the morning and may last an hour or more. This type of stiffness is severe enough to affect movement.
Additional symptoms of RA are:
- Fatigue and loss of energy
- Low-grade fevers
- Appetite loss
- Eye inflammation
- Rheumatoid nodules (firm lumps under the skin near joints that often feel pressure, such as the elbows and fingers)
- Muscle aches
- Malaise (a general unwell feeling)
- Anemia (low number of healthy red blood cells)
Causes
AxSpA and RA are autoimmune diseases—conditions in which the immune system malfunctions and attacks healthy tissues. Researchers do not know why the immune system turns on itself.
They suspect a combination of factors is probably at play. These include having specific genes that make you more vulnerable to disease and environmental triggers like viruses that result in an abnormal immune system response.
Axial Spondyloarthritis
Researchers are working hard to learn what causes axSpA. They know risk factors increase a person’s likelihood of developing axSpA. Having one or more risk factors doesn’t necessarily mean you will go on to develop axSpA. It just means you are more likely to develop the condition.
Risk factors linked to axSpA include:
- Family history and genetics: Your risk is higher if you have a parent, sibling, or child with the condition. AxSpA is also linked to HLA-B27, a genetic marker found in more than 90% of White people with AxSpA. It is found less often in Black people and people of other ethnicities who have AxSpA.
- Environmental triggers: Aspects of your environment may increase the risk of developing axSpA. These include exposure to infections, toxins and pollutants, gut bacteria changes, and chronic stress.
- Lifestyle factors: You might be able to control some lifestyle risk factors for axSpA. For example, lifestyle habits like eating a healthy diet and exercising can help manage or even prevent aspects of axSpA. Vitamin D deficiency and smoking are also known risk factors for axSpA that can be managed.
Rheumatoid Arthritis
Researchers have identified genetic and environmental risk factors that might increase a person’s risk for RA.
Factors that increase incidence include:
- Family history: Much like axSpA, your risk for RA increases if you have a first-degree relative (parent, child, or sibling) with the condition.
- Genetics: Genetic markers specific to RA include the major histocompatibility complex (MHC) locus (the first identified genetic marker important to the immune system) and HLA-DRB1. MHC locus accounts for one-third of genetic susceptibility to RA, while HLA-DRB1 is strongly linked with RA in most populations.
- Sex: People assigned female at birth account for 75% of the people with RA.
- Smoking: This is a known risk factor for RA. Smoking accounts for 20% to 25% of overall RA risk and 35% of ACPA-positive RA (RA defined by the presence of inflammatory markers called anti-cyclic citrullinated protein, or anti-CCP, antibodies).
- Environmental risk factors: Additional environmental risk factors, such as airborne exposures, microbes, infectious agents, diet, and socioeconomic factors (including occupational and recreational exposures) combined with family history and genetics, can contribute to the development of RA.
Diagnosis
There are no single definitive tests to confirm a diagnosis of axSpA or RA. Instead, a healthcare provider will employ various diagnostic tools to determine what might be causing your symptoms. Some of these methods might overlap.
AxSpA and RA share similar symptoms, so it is vital to see a rheumatologist to get an accurate diagnosis. A rheumatologist is a medica doctor (M.D.) who has specialized training in diagnosing and treating autoimmune arthritis conditions like axSpA and RA.
Axial Spondyloarthritis
Early diagnosis of axSpA is vital to preventing damage to the sacroiliac joints and spine the disease is known for causing. Due to its development in younger people and because it causes back pain as the earliest symptom, a diagnosis of axSpA is sometimes delayed.
Many people will seek care from a chiropractor or their primary care provider instead of a rheumatologist who specializes in the condition, which leads to further delays.
Treatments for mechanical back pain cannot stop the inflammation caused by your immune system, so you will continue to experience pain and inflammation, which, over time, can lead to spine damage.
When to Get a Referral to a Rheumatologist
Anyone experiencing back pain that lasts more than three months and seems inflammatory (resolves with NSAIDs and activity, is worse with inactivity, etc.) should request a referral to a rheumatologist.
The diagnostic workup for AxSpA includes medical and family history, physical exam, HLA-B27 genetic marker testing, blood work that looks for markers of inflammation, and imaging studies, including standard X-rays and magnetic resonance imaging (MRI).
Damage from axSpA can take many years to show up on X-rays, and MRI is more reliable for diagnosing the condition and tracking its progression. A diagnosis of axSpA can be confirmed based on your symptoms, family and personal medical history, HLA-B27 positivity, and bone and joint changes being seen on imaging.
Rheumatoid Arthritis
Like axSpA, an early diagnosis is vital to stopping the progression of irreversible joint damage. Studies have found that by the time someone is finally diagnosed with RA, they already have joint changes that can be seen in imaging studies.
RA is diagnosed using your symptom history, family and medical history, a physical examination of the joints and organs, blood work, and imaging studies.
Blood tests used to help in the diagnosis of RA include:
X-rays are typically normal in early RA but can be helpful later on to determine if the disease is progressing. MRI and ultrasound scans might be done to determine the severity of RA.
You should reach out to a healthcare provider if you experience pain, swelling, or stiffness in one or more joints that last for days and weeks and return. You should also reach out for joint pain accompanied by fatigue, fever, or malaise. They can do testing and give you a referral to a rheumatologist.
Treatment
The main goals for treating axSpA and RA are the same—to reduce symptoms, improve quality of life, and slow disease progression. Both these conditions are painful and life-altering, so they require aggressive treatments. Many of those treatments will overlap.
Treatments for axSpA and RA include:
- NSAIDs to bring down inflammation and reduce pain, including over-the-counter (OTC) Advil (ibuprofen) or Aleve (naproxen), and prescription NSAIDs
- Corticosteroids to reduce inflammation during flare-ups
- Conventional disease-modifying antirheumatic drugs (DMARDs) to improve symptoms, reduce inflammation, and slow down progression, such as methotrexate (although it is less effective in axial spondylitis)
- Biologic DMARDs to target specific parts of the immune system to stop it from overacting and attacking itself, such as the tumor necrosis factor (TNF) blockers Enbrel (etanercept), Remicade (infliximab), and Humira (adalimumab), and for ankylosing spondylitis, Cosentyx (secukinumab)
- Janus kinase (JAK) inhibitors to calm the immune and stop damaging inflammation, such as Rinvoq (upadacitinib)
- Physical and occupational therapies to help you keep moving safely
- Lifestyle therapies to manage symptoms and improve mobility
- Surgery to repair or replace damaged joints
Prevention
How to prevent axSpA and RA is unknown and it’s uncertain who might develop these conditions. Because HLA-B27 positivity, RF positivity, and inflammatory marker elevations can occur in otherwise healthy people and are also seen in other autoimmune diseases, these tests are unreliable for identification.
In the future, researchers might have answers. For now, healthcare providers focus on reducing the symptoms of these conditions so they do not progress or cause joint damage and disease complications, such as heart and respiratory failure and life-threatening infections.
Reducing some of your risk factors for axSpA and RA might be possible. For example, avoiding smoking and exposure to pollutants and toxins could potentially reduce risk. But even with managing those risk factors, especially if you have risk factors like family history and genetic disposition, it is still possible to develop axSPA or RA.
Talk to a Healthcare Provider
If you have concerns about your risk for axSpA, RA, or another autoimmune disease, talk to your healthcare provider about ways to manage your risk and about screening options for these conditions to get ahead of any severe problems.
Summary
Axial spondyloarthritis and rheumatoid arthritis are autoimmune diseases where the immune system malfunctions and attacks healthy tissues. With axSpA, those attacks are directed at the spine and sacroiliac joints. With RA, the immune system attacks the synovial joint linings.
Both diseases are systemic, meaning they affect many other body areas and organs. They are also both progressive conditions, which means they get worse with time and can lead to joint damage and other disease complications.
Early diagnosis and treatment can prevent serious problems and allow people with axSpA and RA to continue to have healthy and productive lives.
A Word From Verywell
If you have been diagnosed with axial spondyloarthritis or rheumatoid arthritis, check in regularly with your rheumatologist and follow your treatment plan. Left untreated, these conditions can lead to significant joint damage and life-threatening complications.
Let your healthcare provider know about any new or worsening symptoms you experience. This is the best way to get ahead of any problems. With the help of your rheumatologist, you can manage your condition well and improve your outlook and quality of life.
Frequently Asked Questions
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Is axial spondyloarthritis life-threatening?
Axial spondyloarthritis is not a life-threatening condition. It might be progressive and cause complications that affect spine movement and breathing ability, though. But with today’s treatments, the worst complications can be prevented, and most people can enjoy a good quality of life despite the condition.
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Will rheumatoid arthritis lead to disability?
Rheumatoid arthritis is a debilitating condition that can affect movement and interfere with daily activities, including self-care. It may cause permanent disability due to bone loss and joint deformity. But there are treatment options to prevent these complications.
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What are the complications of autoimmune diseases like axial spondyloarthritis and rheumatoid arthritis?
Complications of autoimmune diseases include vision loss, life-threatening infections, lung and heart problems, and kidney and liver issues. These complications are often linked to ongoing and untreated inflammation or rare cases of severe disease. Prompt diagnosis and treatment can reduce or delay serious complications and improve quality of life.
