• Over time, the symptoms of AS can change.
  • You may also develop related conditions like inflammatory bowel disease or psoriasis.
  • Documenting your health can help you develop a care plan with your doctor.

The symptoms of ankylosing spondylitis (AS) can change over months or years. Even if you’ve successfully managed AS, new or worsening symptoms may mean it’s time to switch treatments.

In addition to AS itself, some people can develop related conditions such as inflammatory bowel disease (IBD) and psoriasis that need treatment.

By documenting changes in your physical health, you can help your doctor determine how your AS may be progressing. Together, you can use that information to find the best treatment plan to manage symptoms and improve quality of life.

Knowing how doctors diagnose AS can help you to gain an understanding of the symptoms you may experience with AS and how they might change over time.

AS is a type of axial spondyloarthritis (axSpA). It causes inflammation of the joints in the spine and pelvis and may also affect other organs.

The joint changes of AS can be seen on an MRI. That’s why AS is also called radiographic axSpA. If you have clinical signs but no visible joint changes on an MRI, you may have a diagnosis of non-radiographic axSpA.

To diagnose AS, doctors refer to features of spondyloarthritis (SpA), a group of conditions that includes axSpA. They start with a single symptom: back pain that has persisted for more than 3 months in people younger than age 45.

Then, doctors will look for other features to have a diagnosis of axSpA. They’ll look for one of the following:

  • inflammation of sacroiliac joints (sacroiliitis) on X-ray, plus one or more SpA feature
  • positive test for HLA-B27 protein plus two or more features of SpA

The list of features of SpA includes many symptoms people may experience in later progression of AS and the related conditions they may develop:

  • family history of SpA
  • positive result for HLA-B27
  • arthritis
  • psoriasis
  • Crohn’s disease or colitis
  • enthesitis (inflammation of areas where tendons and ligaments enter bone) at the heel
  • inflammatory back pain
  • dactylitis (swelling of fingers or toes)
  • uveitis (eye inflammation)
  • elevated C-reactive protein
  • good response to nonsteroidal anti-inflammatory drugs (NSAIDs)

Although a person may receive a diagnosis of AS and not experience related conditions like uveitis and enthesitis, they may develop these if the condition progresses.

Not everyone who has AS experiences all the symptoms. Some people have symptoms that slowly progress over many years, while others have flares when AS is more active.

A common early sign of AS is pain in the lower back and buttocks. This is from inflammation of the sacroiliac joints, which are found between the tailbone and pelvis.

Other signs of AS can include:

  • back pain and stiffness
  • pain in the lower back, spine, buttocks
  • stiffness and pain in other joints such as ribs, shoulder, feet, or knees
  • difficulty taking deep breaths because of rib joint stiffness
  • severe fatigue

The back pain and stiffness may get better with activity. You may have more stiffness in the morning and wake up during the night because of pain.

People with AS are more likely to have other conditions such as:

  • uveitis
  • psoriasis
  • IBD

Someone who has these other conditions may have other AS symptoms such as:

  • vision changes, redness, or swelling of the eye
  • skin rashes
  • unintended weight loss
  • loss of appetite
  • loose bowel movements
  • abdominal pain

AS causes inflammation of the joints in the spine. This leads to pain and stiffness in the back and spinal column. If inflammation progresses, it can make it harder to move the spine.

Eventually, the vertebrae of the spine may fuse together.

A small number of people with AS experience its more advanced stages. Most people with AS keep full function and the ability to work.

Sacroiliitis, or inflammation of the sacroiliac joints, is characteristic of AS. While other conditions can cause sacroiliitis, this type of inflammation is the main symptom of AS. The ability to see sacroiliitis on an MRI or X-ray helps lead to a diagnosis of AS.

A grading system of 0 to 4 defines the progression of sacroiliitis based on joint changes seen on X-ray images:

  • 0: Joint is unchanged.
  • 1: Joint margins are blurred.
  • 2: Joint width unchanged; small areas of erosions or hardening (sclerosis).
  • 3: One or more of the following: erosions, sclerosis, change in joint width, or partial ankylosis (stiffening).
  • 4: Total ankylosis (stiffening).

Stage 3 is considered moderate or advanced sacroiliitis.

MRI is more sensitive for detecting sacroiliitis and is recommended if AS is suspected but the X-ray is negative.

The progression of AS can happen over many years. Tracking your symptoms can help you and your doctor to recognize signs that your AS progression is changing.

You can also spot early signs of related conditions such as uveitis and psoriasis that can get better with treatment.

You can track your symptoms using an online app or a paper-based diary. Here are some factors you may want to track regularly:

  • location of pain and severity
  • stiffness and mobility
  • energy and fatigue
  • weight and appetite
  • exercise and activity
  • skin health
  • digestion
  • medication

Since it can take many years to see changes in symptoms, you may want to keep a journal on a weekly or monthly basis, but increase the frequency to weekly or daily if you notice new symptoms.

The goals of AS treatment are to relieve symptoms and slow the progression of the condition. It also helps to maintain spinal flexibility and keep a good posture.

In a 2019 study of 350 people with AS, the use of tumor necrosis factor inhibitors (TNFi), a type of biologic prescription medication, slowed the rate of AS progression as seen on an X-ray by 20%.

In the early stages of AS, your doctor may recommend managing the condition with movement and over-the-counter medications. As your symptoms change, they may recommend a different treatment regimen.

Treatments for AS include:

  • physical therapy
  • exercise
  • NSAIDs
  • prescription medications such as JAK inhibitors, and biologics
  • surgery

You may want to work with your doctor to change your treatment plan if you have new or worsening symptoms of AS, or if you have signs of a related condition such as IBD.

An example of a new symptom might be having stiffness and pain in joints that previously hadn’t been affected by AS.

Treatment for AS can help you to manage symptoms and maintain mobility.

By documenting new or worsening symptoms, you can work with your doctor to determine whether your AS is progressing or whether you’re experiencing a new condition related to AS. Then, you can decide what changes in treatment might be best for your overall health.