Overview
Ankylosing spondylitis is a long-term inflammatory condition that mainly affects the spine and the sacroiliac joints in the pelvis. It involves inflammation where ligaments and tendons attach to bone, which can gradually lead to stiffness and, in some people, abnormal fusion of the spine. The ongoing inflammation commonly causes pain and morning stiffness that improve with movement, and it can affect posture and chest expansion over time. With the right care plan, many people can maintain mobility and reduce flare-ups.
Symptoms
The most typical symptom is inflammatory back pain, often felt in the lower back or buttocks and worse in the morning or after rest. You may notice stiffness that improves with activity, limited bending of the spine, and pain that may gradually spread upward. Some people also develop pain and swelling in the hips, shoulders, or other joints, along with fatigue. Over time, reduced chest expansion and a more rigid posture can make deep breathing or looking up more difficult.
Causes
Ankylosing spondylitis is caused by an overactive immune response that triggers chronic inflammation, especially at the sacroiliac joints and spine. In many cases, it is associated with the HLA-B27 gene, which increases susceptibility, but it does not guarantee that someone will develop the condition. Environmental triggers may play a role in activating the immune process in genetically susceptible people.
Risk Factors
Risk is higher if you have a family history of ankylosing spondylitis or related inflammatory spine disorders. Being a carrier of HLA-B27 increases the likelihood, particularly in people with symptoms consistent with inflammatory back pain. It also tends to begin in early adulthood, and smoking is known to worsen symptoms and treatment response for many people.
Prevention
While you cannot always prevent ankylosing spondylitis from developing, you can reduce flare-ups and stiffness by staying physically active with daily mobility and strengthening exercises. Quitting smoking and maintaining a healthy body weight can help lessen inflammation and improve function. Practicing good posture and keeping regular follow-up care can also help protect spinal mobility over time.
How the Diagnosis Is Evaluated
Clinicians usually start with a history focused on inflammatory back pain patterns, including morning stiffness, improvement with activity, and symptoms lasting at least several weeks. A physical exam may show reduced lumbar spine motion, tenderness around the sacroiliac joints, and reduced chest expansion. Blood tests such as CRP and ESR can show inflammation, and HLA-B27 may support the diagnosis. Imaging-often X-rays and, when early disease is suspected, MRI of the sacroiliac joints or spine-helps confirm characteristic inflammatory changes.
Nonsurgical Treatment Options
Treatment typically focuses on reducing inflammation, controlling pain, and preserving mobility. Exercise and physical therapy are key and usually include posture training, stretching, and strengthening to maintain spinal range of motion. Nonsteroidal anti-inflammatory drugs (NSAIDs) are commonly used for symptom control, and clinicians may tailor the plan based on your response and tolerance. If symptoms are not controlled, biologic medications such as TNF inhibitors or IL-17 inhibitors can reduce inflammatory activity and improve function. For certain patients with more peripheral joint involvement, sulfasalazine may be considered, and steroid injections may be used selectively for specific areas of inflammation. Because ankylosing spondylitis can also affect the eyes, coordination with an eye specialist is important if eye pain, redness, or light sensitivity occurs.
When to Seek Medical Attention
Seek prompt medical attention if your symptoms rapidly worsen, if you develop new weakness, numbness, or problems walking, or if you cannot function as usual. Get urgent care for red-flag neurologic symptoms such as new bowel or bladder changes, severe or progressive neurologic deficits, or sudden loss of function. You should also seek urgent evaluation for fever with severe back pain, or for eye symptoms like painful red eyes or sudden vision changes, which may indicate uveitis.
Frequently Asked Questions
There is currently no guaranteed cure, but treatment can significantly reduce inflammation, pain, and flare-ups and help preserve mobility.
MRI can detect early sacroiliac joint inflammation before changes appear on plain X-rays.
Next Steps
If you have persistent inflammatory back pain, morning stiffness, or reduced spine mobility, schedule an evaluation with a clinician familiar with inflammatory back disorders. Share your symptom timeline and any family history, and ask whether labs and MRI are appropriate for your situation. Early diagnosis and consistent conservative care can improve comfort and protect long-term function.