If you’ve arrived here after reading my blog, I Knew Something Was Wrong: Twenty Years to Be Heard, you may be wondering exactly what Ankylosing Spondylitis (AS) is and why it took so long to diagnose.
The short answer? Ankylosing Spondylitis is one of many autoimmune diseases, and like many autoimmune conditions, it can be surprisingly difficult to identify.
What Are Autoimmune Diseases?
Autoimmune diseases occur when the body’s immune system mistakenly attacks healthy tissue instead of protecting it.
Researchers have identified between 80 and 100 autoimmune diseases, with some estimates suggesting there may be more than 150 when rarer conditions are included.
Some of the most common autoimmune diseases include:
- Hashimoto’s Thyroiditis
- Rheumatoid Arthritis
- Type 1 Diabetes
- Psoriasis
- Multiple Sclerosis (MS)
- Lupus
- Crohn’s Disease and Ulcerative Colitis
- Graves’ Disease
- Coeliac Disease
- Sjögren’s Syndrome
Autoimmune diseases are far more common than many people realise. In the United States alone, they affect an estimated 50 million people.
They are also notoriously difficult to diagnose because many share similar symptoms, including:
- Fatigue
- Pain
- Inflammation
- Brain fog
- Digestive issues
- Joint problems
Women are particularly affected, accounting for approximately 75–80% of autoimmune disease cases.
Adding to the challenge, people with one autoimmune condition are at greater risk of developing another.
What Is Ankylosing Spondylitis?
Ankylosing Spondylitis is a chronic inflammatory form of arthritis that primarily affects the spine and sacroiliac joints, which connect the spine to the pelvis.
Over time, ongoing inflammation can lead to damage and fusion of the vertebrae, reducing flexibility and mobility. In advanced cases, this can result in what is sometimes called a “bamboo spine.”
While AS is relatively uncommon, affecting around 0.1–0.5% of the population, its impact on daily life can be significant.
Although historically considered a condition that affects mostly men, increasing evidence suggests that women have often been underdiagnosed or misdiagnosed.
Common Symptoms of Ankylosing Spondylitis
One reason AS is often missed is because many of its symptoms can easily be mistaken for more common conditions.
Typical symptoms include:
- Persistent lower back pain
- Pain in the hips or buttocks
- Morning stiffness
- Pain that improves with movement rather than rest
- Fatigue
- Reduced flexibility
However, AS doesn’t always stop at the spine.
Some people also experience:
- Eye inflammation (Uveitis or Iritis)
- Knee, shoulder or other joint pain
- Heel pain
- Digestive issues
- Rarely, heart or lung complications
In my case, Iritis was one of the earliest clues that something more significant was happening.
Why Does Diagnosis Take So Long?
The average diagnosis of Ankylosing Spondylitis is often delayed by 8–10 years, and for many people it takes even longer.
The biggest challenge is that back pain is incredibly common.
Most people with chronic back pain don’t have AS, making it easy for inflammatory pain to be mistaken for stress, posture problems, ageing, sports injuries or overuse.
Many patients spend years moving between different specialists before someone finally joins the dots.
The HLA-B27 Gene Connection
One of the strongest clues for Ankylosing Spondylitis is the presence of the HLA-B27 gene.
Around 90% of people diagnosed with AS carry this genetic marker.
However, having the gene doesn’t automatically mean someone will develop the disease, and some people with AS don’t carry it at all.
That’s why diagnosis relies on a combination of symptoms, imaging and blood tests rather than a single test result.
How Is Ankylosing Spondylitis Diagnosed?
Doctors may use a combination of:
- Medical history and symptoms
- Physical examination
- Blood tests, including HLA-B27 testing
- MRI scans
- X-rays
Because inflammation can begin long before structural damage becomes visible on X-rays, MRI has become an important tool for earlier diagnosis.
Treatment and Living Well with AS
Although there is currently no cure for Ankylosing Spondylitis, effective treatments can significantly reduce symptoms and slow disease progression.
Treatment may include:
- Anti-inflammatory medications (NSAIDs)
- Biologic therapies such as TNF inhibitors
- IL-17 inhibitor medications
- Physical therapy
- Regular exercise and mobility work
For many people, treatment can be life-changing.
The Most Important Thing I Learned
If there’s one message I hope people take away from my story, it’s this:
Don’t ignore persistent symptoms simply because tests are normal or because you’ve been told it’s probably stress.
You know your body better than anyone else.
Ankylosing Spondylitis may be relatively uncommon, but the experience of living with unexplained symptoms is not.
Keep asking questions.
Keep advocating for yourself.
And if you’re still searching for answers, don’t give up.
Sometimes the diagnosis takes far longer than it should.
But answers are possible.