✓ Evidence Based

Ankylosing Spondylitis: Symptoms, Causes, Treatments, and More

Ankylosing Spondylitis is generally considered a relatively rare condition compared to more common autoimmune disorders like rheumatoid arthritis. In general, its prevalence is estimated to be around 0.1% to 1.4% of the global population.

What is Ankylosing Spondylitis?

Ankylosing Spondylitis (AS) is a chronic and progressive inflammatory condition that primarily targets the spine and sacroiliac joints, causing pain, stiffness, and reduced mobility. It’s a form arthritis and falls under the umbrella of autoimmune diseases, where the body’s immune system mistakenly attacks its tissues, leading to inflammation. In AS, this inflammation primarily affects the vertebrae in the spine, leading to the fusion of bones and the formation of bony outgrowths, known as syndesmophytes. This fusion can result in a rigid, hunched posture over time, hence the term “ankylosing,” which means fusion or stiffening. AS can also affect the larger joints and cause pain and stiffness in the hips, knees, and shoulders. While AS predominantly impacts the musculoskeletal system, it can also affect other parts of the body, including the eyes and cause systemic symptoms such as fatigue. This complex condition often manifests in early adulthood and can persist throughout a person’s life, necessitating ongoing management and treatment to alleviate symptoms and maintain quality of life.


It’s important to note that AS is a chronic condition, and its symptoms may come and go over time. The symptoms may range in intensity from mild to severe depending on disease activity and how well managed the condition is. Early diagnosis and appropriate management are key to controlling symptoms and preventing complications. The symptoms of ankylosing spondylitis (AS) can vary from person to person, but they typically include:

  • Chronic Lower Back Pain: persistent and often severe pain in the lower back is a hallmark symptom of AS. The pain tends to worsen after periods of inactivity, such as sleep or prolonged sitting.
  • Stiffness: individuals with AS often experience stiffness in the affected joints, particularly in the morning or after long periods of rest. This stiffness can gradually improve with physical activity.
  • Limited Mobility: reduced flexibility and range of motion in the spine and other affected joints can lead to difficulty in performing daily activities. Over time, AS can result in reduced mobility.
  • Fatigue: many people with AS experience fatigue, which can be both physical and mental. The chronic pain and inflammation associated with AS can contribute to this feeling of tiredness (1).
  • Joint Involvement: AS primarily affects the spine and sacroiliac joints, but it can also cause pain and inflammation in other joints, including the hips, shoulders, and knees.
  • Morning Stiffness: morning stiffness is a common AS symptom that can last for several hours. It often eases with physical activity but can return after periods of rest.
  • Eye Inflammation: some individuals with AS may develop eye inflammation, known as uveitis or iritis. Symptoms can include eye redness, pain, sensitivity to light, and blurred vision. Prompt medical attention is crucial to prevent complications (2).
  • Breathing Difficulties: in advanced cases of AS, the condition can affect the chest, leading to breathing difficulties. This can occur due to the fusion of the ribs with the spine, limiting lung expansion (3).

Summary: Symptoms of ankylosing spondylitis are variable, but commonly include chronic lower back pain, stiffness, reduced range of motion, and pain in the larger joints of the hips, knees, and shoulders. Systemic symptoms of anklylosing spondylitis include fatigue.


The exact cause of ankylosing spondylitis is not fully understood, but it is believed to result from a combination of genetic and environmental factors. AS has a strong genetic component. The presence of a specific genetic marker called HLA-B27 is strongly associated with the development of ankylosing spondylitis. However, not everyone with this marker will develop the condition, and AS can occur in individuals without it.

While genetics play a significant role, environmental factors may also contribute to the development of AS. Infections and other environmental triggers have been suggested as potential factors that can activate the autoimmune response in genetically predisposed individuals.

Summary: The exact cause of anklyosing spondylitis is unknown, but involves a combination of genetic and environmental factors.

Risk Factors

Several risk factors may increase the likelihood of developing ankylosing spondylitis. While the exact cause of AS remains unclear, a combination of genetic and environmental factors is thought to contribute to its development. Here are the primary risk factors associated with AS:

  • Genetic Predisposition: the strongest known risk factor for AS is genetic. The presence of a specific genetic marker called HLA-B27 is strongly associated with AS (4). However, having the HLA-B27 gene does not guarantee that a person will develop the condition. Many individuals with the HLA-B27 marker do not develop AS, and not everyone with AS carries this gene.
  • Family History: AS tends to run in families. If you have a close family member, such as a parent or sibling, with AS, your risk of developing the condition is higher.
  • Gender: AS is more common in men than in women. Men are at a higher risk of developing the condition, though women can still develop AS.
  • Age: symptoms of AS typically appear in late adolescence or early adulthood. While the condition can develop at any age, it most commonly starts in individuals between the ages of 17 and 45.
  • Other Autoimmune Conditions: having other autoimmune conditions, such as psoriasis, inflammatory bowel disease (IBD), or reactive arthritis, may increase the risk of developing AS. These conditions often share genetic and immunological factors.
  • Environmental Factors: while less well-understood, environmental factors such as infections or other triggers have been suggested as potential contributors to AS, especially in genetically predisposed individuals (5). However, more research is needed to fully understand these associations.

It’s important to note that having one or more of these risk factors does not guarantee the development of ankylosing spondylitis. AS is a complex condition influenced by a combination of genetic and environmental factors, and its exact cause remains a subject of ongoing research. If you have a family history of AS or are experiencing symptoms associated with the condition, it’s essential to consult with a healthcare professional for a thorough evaluation and diagnosis. Early diagnosis and appropriate management can help individuals with AS lead healthier lives and manage their symptoms effectively.

Summary: The strongest risk factor for ankylosing spondylitis is genetics, but family history, male gender, age, and environmental factors such as infections also play a role.


Diagnosing ankylosing spondylitis can be challenging, as its symptoms can overlap with other conditions. A thorough evaluation by a rheumatologist is essential. The diagnostic process typically includes:

  • Medical History and Physical Examination: the healthcare provider will ask about your symptoms, medical history, and family history. A physical examination will assess your range of motion, joint tenderness, and signs of inflammation.
  • Blood Tests: blood tests may be conducted to check for markers of inflammation, such as C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR). The presence of the HLA-B27 gene marker may also be tested.
  • Imaging Studies: X-rays, MRI, and CT scans can reveal changes in the spine and sacroiliac joints. These imaging studies can help confirm the diagnosis and assess disease progression.
  • Assessment of Mobility: the healthcare provider may assess your spinal mobility by measuring the distance between your fingertips and the floor when bending forward. Reduced mobility is a common sign of AS. Your ribcage expansion while taking a deep breath may also be measured.
  • Assessment of Eye Inflammation: regular eye examinations may be recommended to detect and manage eye inflammation associated with AS.

Summary: Diagnosis of ankylosing spondylitis involves a combination of medical history, physical examination, blood tests, and imaging studies.


There is no cure for ankylosing spondylitis, but various treatment options are available to manage symptoms and improve quality of life. Treatment strategies often involve a multidisciplinary approach, including medications, physical therapy, and lifestyle modifications.


Medication management plays a vital role in the comprehensive treatment of ankylosing spondylitis. An effective medication strategy aims to alleviate pain, reduce inflammation, improve mobility, and slow the progression of the disease. However, it’s essential for individuals with AS to work closely with their healthcare providers to determine the most appropriate medications, dosages, and treatment plans tailored to their unique needs. Regular monitoring and adjustments to the medication regimen, when necessary, can help individuals with AS effectively manage their condition and maintain a good quality of life. Several different classes of medications are used to address treatment goals. The most commonly used medications include:

  • Nonsteroidal Anti-Inflammatory Drugs (NSAIDs): NSAIDs, such as ibuprofen or naproxen, are often used as first-line treatment to reduce pain and inflammation.
  • Disease-Modifying Antirheumatic Drugs (DMARDs): in some cases, DMARDs like sulfasalazine may be prescribed to manage AS symptoms and slow the progression of disease activity.
  • Biologics: biologic medications, such as tumor necrosis factor (TNF) inhibitors like etanercept, adalimumab, and infliximab, target the immune system to reduce inflammation and slow disease progression.
  • Corticosteroids: strong anti-inflammatory medication that can provide short-term relief during flare-ups.
  • Pain Medications: in severe cases, pain medications may be prescribed to manage chronic pain associated with AS.

Other Treatment Options

The following treatment options are usually used in combination with medication management and include the following:

  • Physical Therapy: physical therapy is an essential component of AS management. A physical therapist can provide exercises and stretches to improve flexibility, posture, and muscle strength. These exercises help reduce pain and maintain joint mobility.
  • Lifestyle Modifications: lifestyle modifications include regular, low-impact exercise such as swimming and walking can help maintain joint mobility and reduce stiffness. Focusing on posture can minimize stress on the spine and improve overall comfort. Quitting smoking is crucial, as smoking can worsen AS symptoms and increase the risk of complications.
  • Surgery: in rare cases, surgery may be recommended to correct severe deformities or address complications of AS, such as hip replacement surgery.
  • Psychological Support: living with a chronic condition like AS can be emotionally challenging (6). Seeking support from a mental health professional or joining a support group can help individuals cope with the psychological impact of the disease.

Summary: Treatment of anklyosing spondylitis involves medication management and a combination of physical therapy, exercise, quitting smoking, and psychological support. In rare cases surgery may be required.


Ankylosing spondylitis is a chronic inflammatory autoimmune disorder that primarily affects the spine and sacroiliac joints. It can cause significant pain, stiffness, and reduced mobility, impacting a person’s quality of life. While there is no cure for AS, various treatment options are available to manage symptoms and slow disease progression.

Early diagnosis and a comprehensive treatment plan that includes medications, physical therapy, and lifestyle modifications can help individuals with AS lead fulfilling lives. It’s essential for those experiencing symptoms of AS to seek medical attention promptly to receive an accurate diagnosis and appropriate care. With proper management, individuals with ankylosing spondylitis can improve their quality of life and maintain their mobility for years to come.