Diffuse idiopathic skeletal hyperostosis (DISH) and ankylosing spondylitis (AS) are different types of arthritis that cause pain and stiffness. While some symptoms of these conditions may overlap, DISH and AS also have distinctions that set them apart from one another.

DISH, which is also sometimes called Forestier’s disease, occurs when ligaments and tendons harden and form painful bone spurs. Typically, DISH affects the spine, but it can also cause bone spurs in the hips, shoulders, feet, hands, knees, and other parts of the body.

AS causes inflammation in the joints and ligaments of the spine. In some cases, this inflammation can trigger new bone formation, which results in sections of the spine being fused together. AS can also affect the shoulders, ribs, hips, hands, feet, heels, and other areas of the body.

The good news is certain lifestyle measures and treatments can help people with both DISH and AS find relief, increase their mobility, and improve their quality of life.

In this article, we compare causes, symptoms, diagnosis, and treatment for these two conditions.

While DISH and AS cause similar symptoms and may require comparable treatments, they also exhibit clear differences.


Distinctions between the two conditions include:

Symptomsmay cause numbness, tingling, trouble swallowing, hoarseness, or paralysis if nerves or the spinal cord become compressedcan cause weight loss, fatigue, skin rashes, stomach pain, trouble breathing, or loose bowel movements
Age of onsetusually develops in people over age 50symptoms generally occur before the age of 45
Causeresearchers have identified some risk factors for DISHcertain gene mutations and a family history are more strongly linked to AS
Other medical conditionsthe risk of developing DISH is higher if you have diabetes or obesitythe likelihood of having AS increases if you have certain gastrointestinal diseases or psoriasis
Blood teststhere’s no screening or diagnostic blood test for DISHa blood test to look for gene variations can help determine a person’s risk for AS
Complicationsmay lead to sleep apnea or difficulty swallowingcould present heart issues, osteoporosis, and uveitis


Similarities between DISH and AS include:

  • Pain and stiffness are common symptoms.
  • Being male is a risk factor for both conditions.
  • Researchers don’t know exactly what causes either condition.
  • There’s no cure for DISH or AS.
  • Physical therapy, pain relievers, and steroid injections are recommended for both conditions.
  • Imaging tests are used to help diagnose DISH and AS.
  • Both conditions increase a person’s risk of fractures.

Pain and stiffness are hallmark symptoms of both DISH and AS, but these conditions can prompt other issues as well.

Symptoms of DISH

Often, people with DISH don’t have any symptoms. When issues do occur, they may include:

  • stiffness or pain, especially in the neck or upper back
  • limited range of motion in the back
  • trouble swallowing or hoarseness if the nerves in the neck become compressed
  • numbness or tingling in the legs if nerves in the lower back are compressed
  • paralysis if the spinal cord is compressed

Symptoms of ankylosing spondylitis (AS)

Lower back and hip pain or stiffness are the most common problems associated with AS. Symptoms vary from person to person. Some people experience issues that come and go, while others deal with chronic, daily pain.

A person’s AS symptoms may worsen when they have a “flare” (a period of increased disease activity).

Other symptoms of AS may include:

  • pain, inflammation, and stiffness in the ribs, neck, knees, feet, or shoulders
  • trouble breathing if the joints connecting the ribs are affected
  • vision problems or inflammation of the eye
  • fatigue
  • weight loss or loss of appetite
  • rashes
  • stomach pain
  • loose bowel movements

Researchers don’t know the exact cause of either DISH or AS, but they’ve identified certain risk factors that may increase a person’s chances of developing these conditions.

Risk factors for DISH

You may be more prone to DISH if you:

  • are a male
  • are older than age 50
  • have taken the acne medicine isotretinoin (Amnesteem, Claravis, and others)
  • have diabetes or another condition that causes increased insulin levels
  • are part of the Pima, a group of Native Americans that primarily lives in Arizona
  • have abnormal spine anatomy
  • frequently move or lift heavy objects (this risk is controversial)

Risk factors for ankylosing spondylitis (AS)

Research suggests that both genes and the environment likely play a role in the development of AS. Having certain genetic changes, or mutations, increases the risk of AS in some, but not all, people.

According to the National Institutes of Health (NIH), approximately 9 out of 10 people with AS carry the HLA-B27 gene. However, the NIH estimates that only 8 out of 100 people who have the HLA-B27 gene will develop AS.

It’s also possible for children to inherit AS from a parent. A parent with AS who carries the HLA-B27 gene could pass this gene on to their children. The NIH estimates that 5% to 20% of children with the HLA-B27 gene will develop AS.

Other risk factors for AS include:

Diagnosing DISH and AS is sometimes tricky for doctors. The process can involve performing different tests as well as using certain methods to rule out other conditions.

Diagnosing DISHDiagnosing AS
Doctors may perform imaging tests, such as computed tomography (CT) scans or X-rays, to look for bony growths.There isn’t one, conclusive test to help diagnose AS, doctors may recommend imaging tests, such as magnetic resonance imaging (MRI) or X-rays.
Other tests can also help rule out conditions that may trigger similar symptoms.Blood tests to look for the HLA-B27 gene can also be used to help diagnose AS.

There’s no cure for either DISH or AS, but treatments can help alleviate bothersome symptoms and stop them from worsening.

DISH treatmentAS treatment
pain relievers, such as acetaminophen or nonsteroidal anti-inflammatory drugs (NSAIDs)NSAIDs, such as ibuprofen (Advil) or naproxen (Aleve)
corticosteroid injectionsdisease modifying anti-rheumatic drugs (DMARDs)
exercise and physical therapy to help improve range of motion and stiffnessbiologics, such as tumor necrosis factor (TNF) inhibitors and interleukin inhibitors (IL-17)
heat therapysteroid injections
programs to help people manage weight and blood sugar levelsexercise or physical therapy
orthotics to aid walkingsurgery, such as joint replacement procedures or kyphoplasty to correct a curved spine
surgery (if bone spurs compress the spinal cord or affect a person’s ability to swallow)

Certain complications can occur with both DISH and AS, including:

DISH complicationsAS complications
greater risk for bone breaksspinal fractures
loss of mobilityfused vertebrae
chronic paininflammation of the eye (uveitis)
sleep apnea (a condition characterized by interrupted episodes of breathing during sleep)kyphosis (a forward curvature of the spine)
difficulty swallowingosteoporosis
difficulty breathingheart problems
jaw inflammation
nerve scarring and inflammation
chest pain that could affect breathing

DISH and AS are different forms of arthritis that can negatively affect a person’s life.

Pain and stiffness are common symptoms associated with both conditions, but there are also differences between the two. DISH is characterized by painful bone spurs, while AS causes inflammation in the joints and ligaments of the spine.

There’s no cure for DISH or AS, but treatments are available that can help you feel better and live a full life.