Early symptoms of ankylosing spondylitis might include back pain and stiffness in the lower back and hips, especially in the morning and after periods of inactivity. Neck pain and fatigue also are common. Over time, symptoms might worsen, improve or stop at irregular intervals.

The areas most commonly affected are:

• The joint between the base of the spine and the pelvis.
• The vertebrae in the lower back.
• The places where tendons and ligaments attach to bones, mainly in the spine, but sometimes along the back of the heel.
• The cartilage between the breastbone and the ribs.
• The hip and shoulder joints.

Seek medical attention if you have low back or buttock pain that came on slowly, is worse in the morning or awakens you from your sleep in the second half of the night — particularly if this pain improves with exercise and worsens with rest. See an eye specialist immediately if you develop a painful red eye, severe light sensitivity or blurred vision.

Ankylosing spondylitis has no known specific cause, though genetic factors seem to be involved. In particular, people who have a gene called HLA-B27 are at a greatly increased risk of developing ankylosing spondylitis. However, only some people with the gene develop the condition.

Onset generally occurs in late adolescence or early adulthood. Most people who have ankylosing spondylitis have the HLA-B27 gene. But many people who have this gene never develop ankylosing spondylitis.

In severe ankylosing spondylitis, new bone forms as part of the body's attempt to heal. This new bone gradually bridges the gap between vertebrae and eventually fuses sections of vertebrae. Those parts of the spine become stiff and inflexible. Fusion also can stiffen the rib cage, restricting lung capacity and function.

Other complications might include:

• Eye inflammation, called uveitis. One of the most common complications of ankylosing spondylitis, uveitis can cause rapid-onset eye pain, sensitivity to light and blurred vision. See your health care provider right away if you develop these symptoms.
• Compression fractures. Some people's bones weaken during the early stages of ankylosing spondylitis. Weakened vertebrae can crumple, increasing the severity of a stooped posture. Vertebral fractures can put pressure on and possibly injure the spinal cord and the nerves that pass through the spine.
• Heart problems. Ankylosing spondylitis can cause problems with the aorta, the largest artery in the body. The inflamed aorta can enlarge to the point that it distorts the shape of the aortic valve in the heart, which impairs its function. The inflammation associated with ankylosing spondylitis increases the risk of heart disease in general.

During the physical exam, your health care provider might ask you to bend in different directions to test the range of motion in your spine. Your provider might try to reproduce your pain by pressing on specific portions of your pelvis or by moving your legs into a particular position. You also may be asked to take a deep breath to see if you have difficulty expanding your chest.

Imaging tests

X-rays allow doctors to check for changes in joints and bones, also called radiographic axial spondyloarthritis, though the visible signs of ankylosing spondylitis, also called axial spondyloarthritis, might not be evident early in the disease.

MRI uses radio waves and a strong magnetic field to provide more-detailed images of bones and soft tissues. MRI scans can reveal evidence of nonradiographic axial spondyloarthritis earlier in the disease process, but they are much more expensive.

Lab tests

There are no specific lab tests to identify ankylosing spondylitis. Certain blood tests can check for markers of inflammation, but many different health problems can cause inflammation.

Blood can be tested for the HLA-B27 gene. But many people who have the gene don't have ankylosing spondylitis, and people can have the disease without having the HLA-B27 gene.

The goal of treatment is to relieve pain and stiffness and prevent or delay complications and spinal deformity. Ankylosing spondylitis treatment is most successful before the disease causes irreversible damage.

Medications

Nonsteroidal anti-inflammatory drugs (NSAIDs) — such as naproxen sodium (Aleve) and ibuprofen (Advil, Motrin IB, others) — are the medicines health care providers most commonly use to treat axial spondyloarthritis and nonradiographic axial spondyloarthritis. These medicines can relieve inflammation, pain and stiffness, but they also might cause gastrointestinal bleeding.

If NSAIDs aren't helpful, your doctor might suggest starting a tumor necrosis factor (TNF) blocker or an interleukin-17 (IL-17) inhibitor. These medicines are injected under the skin or through an intravenous line. Another option is a Janus kinase (JAK) inhibitor. Janus kinase (JAK) inhibitors are taken by mouth. These types of medicines can reactivate untreated tuberculosis and make you more prone to infections.

Examples of TNF blockers include:

• Adalimumab (Humira).
• Certolizumab pegol (Cimzia).
• Etanercept (Enbrel).
• Golimumab (Simponi).
• Infliximab (Remicade).

Interleukin-17 (IL-17) inhibitors used to treat ankylosing spondylitis include secukinumab (Cosentyx) and ixekizumab (Taltz). Janus kinase (JAK) inhibitors available to treat ankylosing spondylitis include tofacitinib (Xeljanz) and upadacitinib (Rinvoq).

Therapy

Physical therapy is an important part of treatment and can provide a number of benefits, from pain relief to improved strength and flexibility. A physical therapist can design specific exercises for your needs. To help preserve good posture, you may be taught:

• Range-of-motion and stretching exercises.
• Strengthening exercises for abdominal and back muscles.
• Proper sleeping and walking positions.

Surgery

Most people with ankylosing spondylitis or nonradiographic axial spondyloarthritis don't need surgery. Surgery may be recommended if you have severe pain or if a hip joint is so damaged that it needs to be replaced.

Lifestyle choices also can help manage ankylosing spondylitis.

• Stay active. Exercise can help ease pain, maintain flexibility and improve your posture.
• Don't smoke. If you smoke, quit. Smoking is generally bad for your health, but it creates additional problems for people with ankylosing spondylitis, including further hampering breathing.
• Practice good posture. Practicing standing straight in front of a mirror can help you avoid some of the problems associated with ankylosing spondylitis.

The course of your condition can change over time, and you might have painful episodes and periods of less pain throughout your life. But most people are able to live productive lives despite a diagnosis of ankylosing spondylitis.

You might want to join an online or in-person support group of people with this condition, to share experiences and support.

You might first bring your symptoms to the attention of your family health care provider. Your provider may refer you to a specialist in inflammatory disorders called a rheumatologist.

Here's some information to help you get ready for your appointment.

What you can do

Make a list of:

• Your symptoms, including any that may seem unrelated to the reason you made the appointment, and when they began.
• Key personal information, including major stresses, recent life changes and family medical history.
• All medicines, vitamins and other supplements you take and their doses.
• Questions to ask your doctor.

Take a family member or friend along, if possible, to help you remember the information you're given.

For ankylosing spondylitis, basic questions to ask your health care team include:

• What's likely causing my symptoms?
• Other than the most likely cause, what are other possible causes for my symptoms?
• What tests do I need?
• Is my condition likely temporary or lifelong?
• What's the best course of action?
• What are the alternatives to the primary approach you're suggesting?
• I have other health conditions. How can I best manage them together?
• Are there restrictions I need to follow?
• Should I see a specialist?
• Are there brochures or other printed material I can have? What websites do you recommend?

What to expect from your doctor

Your doctor is likely to ask you questions, such as:

• Where is your pain?
• How severe is your pain?
• Have your symptoms been continuous or occasional?
• What, if anything, seems to worsen or improve your symptoms?
• Have you taken medicines to relieve the pain? What helped most?