Symptoms of Ankylosing Spondylitis

Ankylosing spondylitis (AS) is a type of inflammatory arthritis that affects the joints and ligaments in the spine. Early signs and symptoms of AS include pain and stiffness in the lower back, especially after periods of rest or inactivity. People with AS may also experience fatigue, neck pain, and unintentional weight loss.

No two people experience AS the same way. But generally, symptoms develop gradually over time and tend to come and go. Many people living with AS experience flares—or periods when symptoms get worse. Symptoms can also reduce or temporarily disappear, which is a period called remission. You may experience cycles of flares and remission throughout your life.

AS is a lifelong and progressive disease. Recognizing the symptoms of AS can help you seek out a healthcare provider, receive a proper diagnosis, and get started on treatment sooner. Early treatment is key, as it can help you manage symptoms, slow disease progression, and improve your overall quality of life. 

Low Back Pain and Stiffness 

Pain and stiffness in the lower back is the most common symptom of AS. This occurs when inflammation affects the joints between the pelvic bone and the base of the spine (called the sacroiliac joints). 

AS pain and stiffness typically comes on gradually and may feel like a “dull” pain felt on one side of the back at first. You might also notice that you feel stiffness or pain at night or after long periods of activity—a symptom that may cause discomfort while you sleep.

The good news is that light physical activity (e.g., stretching or yoga) or taking a warm after you wake up usually helps relieve back aches in the morning.

Ankylosing Spondylitis Photo Composite

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Joint Pain 

The inflammation that AS causes can spread to other joints, leading to pain in the hips, shoulders, ankles, knees, and elbows. About 15% of people with AS also experience jaw pain.

The severity of joint pain varies from person to person. Joint pain might occur during flares or become more persistent as your condition progresses. As AS advances, the joint pain between the spine and ribs can worsen, sometimes making it challenging to take a deep breath.


Enthesitis is inflammation of the entheses, or areas where your tendons or ligaments attach to your bone. Enthesitis is common and can cause pain and tenderness in many areas of the body.

However, most people with AS feel tenderness in the heel of one or both feet, which can make it painful to walk. Over time, inflammation can cause bone loss or lead to abnormal bone growth, causing painful bone spurs—or small bumps of extra bone that attach to your existing bones. 


Nearly 90% of people with AS experience fatigue, which can significantly affect your daily functioning and quality of life.

Several factors may contribute to fatigue in people with AS, including:

  • Inflammation may force your body to expend too much energy trying to repair damaged tissues
  • Chronic pain can make it difficult to sleep, contributing to fatigue and grogginess 
  • The psychological impact of living with a progressive condition like AS can lower your energy levels and interfere with your ability to get a good night’s sleep 

Anterior Uveitis 

Anterior uveitis—also known as iritis—is inflammation that affects the middle layer of the eye, specifically the colored ring around the pupil, which is called the iris. Signs and symptoms of anterior uveitis include eye pain, redness, light sensitivity, and blurred vision. These symptoms may suddenly appear and can be severe.

If you notice these symptoms, it’s a good idea to seek medical attention from an eye care specialist (e.g., an optometrist or ophthalmologist) sooner rather than later. If left untreated, anterior uveitis can lead to serious complications, such as glaucoma, cataracts, or vision loss. 

Limited Mobility 

As AS progresses, inflammation can cause the spine and other joints to become stiff and rigid—leading to a loss of flexibility and mobility. In severe cases of AS, the spinal vertebrae may become fused together, which can cause a hunched-over posture. This can make bending, twisting, or rotating the body difficult.

Limited mobility caused by AS can have a significant effect on daily living. You might experience challenges with everyday activities like getting dressed, bathing, and cooking. Losing your range of mobility might also make it difficult for you to work or participate in leisure activities. 

Other Symptoms 

AS-related inflammation can affect more than just the spine. The inflammation can cause symptoms in other parts of your body, including: Other body systems can also be affected and may lead to additional symptoms, including:

Flare Symptoms 

Every person from AS experiences flares differently. Flares can range from mild to severe, last a few days to several weeks, and may be localized or generalized. Localized flares affect only a specific body part, such as a single joint or the lower back. Generalized flares may cause more widespread symptoms in several parts of your body.

Flare symptoms can vary widely among people with AS, but common symptoms may include:

  • Increased pain and stiffness in the lower back and neck
  • Tenderness in other joints (e.g., shoulders, hips, ribs, knees) 
  • Fatigue
  • Mild fever
  • Mood changes
  • Lack of appetite and weight loss 

Symptoms in Children 

Although most people with AS receive their diagnosis during adulthood, some children and teens can also develop the condition. Between 10% to 20% of adults living with AS first experienced their symptoms during childhood—a condition called juvenile ankylosing spondylitis (JAS). 

JAS is 2-3 times more common in males than females. Common symptoms of JAS include:

  • Back pain and stiffness that occurs at night or early in the morning 
  • Swelling in the ankles, heels, buttocks, toes, knees, ribs, upper back, shoulders, and neck 
  • Stooped posture
  • Fatigue
  • Shortness of breath
  • Mild fever 

Symptoms in Women 

Though back pain is a key characteristic of AS in both women and men, symptoms can look different among women and men—which can sometimes lead to a delayed or incorrect medical diagnosis in women. Research shows that women with AS have:

  • More pain in the neck, knees and hips
  • Significantly higher rates of night pain and sleep disturbances or discomfort 
  • Intense fatigue 
  • Loss of flexibility in the spine and other joints 
  • Longer duration of morning stiffness 

Men and women often experience different AS-related complications, too. For example, women are more likely to have inflammatory bowel disease and psoriasis, whereas men are more likely to experience anterior uveitis (iritis). 

When to See a Healthcare Provider 

You may want to visit your healthcare provider if you notice AS symptoms, particularly morning back pain and stiffness that gets better with physical activity. During your appointment, mention any other symptoms you have, such as fatigue or joint pain. 

Your provider will likely perform a physical exam or order blood tests or imaging studies to learn more about your symptoms. They may also refer you to a rheumatologist, or a doctor who specializes in the joints, muscles, and bones, to help them make an official AS diagnosis. 

A Quick Review 

Ankylosing spondylitis is a type of inflammatory arthritis that affects the joints and ligaments of the spine. Pain and stiffness in the lower back and hips, especially in the mornings or after periods of inactivity, is the hallmark symptom of AS. Inflammation can also cause fatigue and joint pain in other parts of the body, including the neck, shoulders, and ankles. 

If you have symptoms of AS, it’s good practice to make an appointment with your healthcare provider. Though AS is a lifelong condition, the good news is that treatment can help you manage symptoms and slow disease progression.

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