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January 2013

Questions and Answers about

Ankylosing Spondylitis

This booklet contains general information

about ankylosing spondylitis (AS). It describes

what ankylosing spondylitis is, its causes, and

treatment options. Highlights of current

research are also included. At the end is a list

of key words to help you understand the terms

used in this booklet. If you have further

questions, you may wish to discuss them with

your health care provider.

What Is Ankylosing Spondylitis?

Ankylosing spondylitis is a form of progressive

arthritis due to chronic inflammation of the

joints in the spine. Its name comes from the

Greek words “ankylos,” meaning stiffening of a

joint, and “spondylo,” meaning vertebra.

Spondylitis refers to inflammation of the spine

or one or more of the adjacent structures of the

vertebrae.

Ankylosing spondylitis belongs to a group of

disorders called seronegative

spondyloarthropathies. Seronegative means

an individual has tested negative for an

autoantibody called rheumatoid factor. The

spondyloarthropathies are a family of similar

diseases that usually cause joint and spine

inflammation. Other well-established

syndromes in this group include psoriatic

arthritis, the arthritis of inflammatory bowel

disease, chronic reactive arthritis, and

enthesitis-related idiopathic juvenile arthritis.

Although these disorders have similarities, they

also have features that distinguish them from

one another. The hallmark of ankylosing

spondylitis is “sacroiliitis,” or inflammation of

the sacroiliac (SI) joints, where the spine joins

the pelvis.

In some people, ankylosing spondylitis can

affect joints outside of the spine, like the

shoulders, ribs, hips, knees, and feet. It can

also affect entheses, which are sites where the

tendons and ligaments attach to the bones. It

is possible that it can affect other organs, such

as the eyes, bowel, and—more rarely—the

Share

Questions and Answers About Ankylosing Spondylitis http://www.niams.nih.gov/Health_Info/Ankylosing_Spondylitis/

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heart and lungs.

Although many people with ankylosing

spondylitis have mild episodes of back pain

that come and go, others have severe,

ongoing pain accompanied by loss of flexibility

of the spine. In the most severe cases,

long-term inflammation leads to calcification

that causes two or more bones of the spine to

fuse. Fusion can also stiffen the rib cage,

resulting in restricted lung capacity and

function.

Who Has Ankylosing Spondylitis?

What Causes Ankylosing Spondylitis?

How Is Ankylosing Spondylitis

Diagnosed?

What Type of Doctor Diagnoses and

Treats Ankylosing Spondylitis?

Can Ankylosing Spondylitis Be Cured?

What Medications Are Used to Treat

Ankylosing Spondylitis?

Will Diet and Exercise Help?

When Might Surgery Be Necessary,

and How Can It Help?

What Are Some Things I Can Do to

Help Myself?

What Is the Prognosis for People With

Ankylosing Spondylitis?

What Research Is Being Conducted on

Ankylosing Spondylitis?

Where Can I Find More Information

About Ankylosing Spondylitis?

Key Words

Who Has Ankylosing Spondylitis?

Ankylosing spondylitis typically begins in

adolescents and young adults, but affects

people for the rest of their lives. Men are more

likely to develop ankylosing spondylitis than

are women.

What Causes Ankylosing

Spondylitis?

The cause of ankylosing spondylitis is

unknown, but it is likely that both genes and

factors in the environment play a role. The

main gene associated with susceptibility to

ankylosing spondylitis is called HLA-B27. But

while most people with ankylosing spondylitis

have this genetic marker, only a small

percentage of people with the gene develop

Questions and Answers About Ankylosing Spondylitis http://www.niams.nih.gov/Health_Info/Ankylosing_Spondylitis/

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the disease.

How Is Ankylosing Spondylitis

Diagnosed?

A diagnosis of ankylosing spondylitis is based

largely on the findings of a medical history and

physical exam. Radiologic tests and lab tests

may be used to help confirm a diagnosis, but

both have some limitations.

Medical History

The medical history involves answering

questions, such as the following:

How long have you had pain?

Where specifically is the pain in your

back or neck? Are other joints

affected?

Is back pain better with exercise and

worse after inactivity, such as when

you first get up in the morning?

Do you have other problems, such as

eye problems or fatigue?

Does anyone in your family have back

problems or arthritis?

Have you recently suffered from a

gastrointestinal illness?

Do you have any skin rashes such as

psoriasis?

From your answers to these questions, your

doctor can begin to get an idea of the

diagnosis.

Physical Exam

During the physical exam, the doctor will look

for signs and symptoms that are consistent

with ankylosing spondylitis. These include pain

along the spine and/or in the pelvis, sacroiliac

joints, heels, and chest. Your doctor may ask

you to move and bend in different directions to

check the flexibility of your spine and to

breathe deeply to check for any problems with

chest expansion, which could be caused by

inflammation in the joints where the ribs attach

to the spine.

Radiologic Tests

X ray and magnetic resonance imaging (MRI)

may be used in making or confirming a

diagnosis of ankylosing spondylitis, but these

tests have limitations. X rays may show

changes in the spine and sacroiliac joints that

Questions and Answers About Ankylosing Spondylitis http://www.niams.nih.gov/Health_Info/Ankylosing_Spondylitis/

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indicate ankylosing spondylitis; however, it

may take years of inflammation to cause

damage that is visible on x rays. MRI may

allow for earlier diagnosis, because it can

show damage to soft tissues and bone before

it can be seen on an x ray. However, MRI is

very expensive. Both tests may also be used to

monitor the progression of ankylosing

spondylitis.

Lab Tests

The main blood test for ankylosing spondylitis

is one to check for the HLA-B27 gene, which is

present in the majority of Caucasians with

ankylosing spondylitis. However, this test also

has limitations. The gene is found in much

lower percentages of African Americans with

ankylosing spondylitis and in ankylosing

spondylitis patients from some Mediterranean

countries. Also, the gene is found in many

people who do not have ankylosing

spondylitis, and will never get it. Still, when the

gene is found in people who have symptoms of

ankylosing spondylitis and/or x-ray evidence of

ankylosing spondylitis, this finding helps

support the ankylosing spondylitis diagnosis.

What Type of Doctor Diagnoses and

Treats Ankylosing Spondylitis?

The diagnosis of ankylosing spondylitis is

often made by a rheumatologist, a doctor

specially trained to diagnose and treat arthritis

and related conditions of the musculoskeletal

system. However, because ankylosing

spondylitis can affect different parts of the

body, a person with the disorder may need to

see several different types of doctors for

treatment. In addition to a rheumatologist,

there are many different specialists who treat

ankylosing spondylitis. These may include:

An ophthalmologist, who treats eye

disease.

A gastroenterologist, who treats

bowel disease.

A physiatrist, a medical doctor who

specializes in physical medicine and

rehabilitation.

A physical therapist or rehabilitation

specialist, who supervises stretching

and exercise regimens.

Often, it is helpful to the doctors and the

patient for one doctor to manage the complete

treatment plan.

Questions and Answers About Ankylosing Spondylitis http://www.niams.nih.gov/Health_Info/Ankylosing_Spondylitis/

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Can Ankylosing Spondylitis Be

Cured?

There is no cure for ankylosing spondylitis, but

some treatments relieve symptoms of the

disorder and may possibly prevent its

progression. In most cases, treatment involves

a combination of medication, exercise, and

self-help measures. In some cases, surgery

may be used to repair some of the joint

damage caused by the disease.

What Medications Are Used to Treat

Ankylosing Spondylitis?

Several classes of medications are used to

treat ankylosing spondylitis. Because there are

many medication options, it’s important to work

with your doctor to find the safest and most

effective treatment plan for you. A treatment

plan for ankylosing spondylitis will likely

include one or more of the following:

Nonsteroidal Anti-Inflammatory Drugs

(NSAIDs)

These drugs relieve pain and inflammation,

and are commonly used to treat ankylosing

spondylitis. Aspirin, ibuprofen, and naproxen

are examples of NSAIDs.1

 All NSAIDs work

similarly by blocking substances called

prostaglandins that contribute to inflammation

and pain. However, each NSAID is a different

chemical, and each has a slightly different

effect on the body.

1

 Warning: NSAIDs can cause stomach

irritation or, less often, they can affect kidney

function. The longer a person uses NSAIDs,

the more likely he or she is to have side

effects, ranging from mild to serious. Many

other drugs cannot be taken when a patient is

being treated with NSAIDs, because NSAIDs

alter the way the body uses or eliminates these

other drugs. Check with your health care

provider or pharmacist before you take

NSAIDs. Also, NSAIDs sometimes are

associated with serious gastrointestinal

problems, including ulcers, bleeding, and

perforation of the stomach or intestine. People

over age 65 and those with any history of

ulcers or gastrointestinal bleeding should use

NSAIDs with caution.

Some NSAIDs are available over the counter,

but more than a dozen others, including a

subclass called COX-2 inhibitors, are available

only with a prescription.

Questions and Answers About Ankylosing Spondylitis http://www.niams.nih.gov/Health_Info/Ankylosing_Spondylitis/

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All NSAIDs can have significant side effects,

and for unknown reasons, some people seem

to respond better to one NSAID than another.

Anyone taking NSAIDs regularly should be

monitored by a doctor.

Corticosteroids

These strong inflammation-fighting drugs are

similar to the cortisone made by our bodies. If

NSAIDs alone do not control inflammation in

people with ankylosing spondylitis, doctors

may inject corticosteroids directly into the

affected joints to bring quick, but temporary

relief. Injections may be given to the sacroiliac

joint, hip joint, or knee joint, but are not given

in the spine.

Disease-Modifying Antirheumatic

Drugs (DMARDs)

These drugs work in different ways to control

the disease process of ankylosing spondylitis.

The most commonly used DMARDs for

ankylosing spondylitis are sulfasalazine and

methotrexate.

Biologic Agents

Members of this relatively new class of

medications are genetically engineered to

block proteins involved in the body’s

inflammatory response. Four biologics

—adalimumab, etanercept, golimumab, and

infliximab—are approved by the Food and

Drug Administration (FDA) for treating

ankylosing spondylitis. All four work by

suppressing a protein called tumor necrosis

factor-alpha (TNF-α), and are often effective

for relieving symptoms when NSAIDs or other

treatments are not. These drugs are taken by

intravenous infusion or injection.

Will Diet and Exercise Help?

A healthy diet and exercise are good for

everyone, but may be especially helpful if you

have ankylosing spondylitis.

Although there is no specific diet for people

with ankylosing spondylitis, maintaining a

healthy weight is important for reducing stress

on painful joints. In people with rheumatoid

arthritis, another inflammatory joint disease, a

diet high in omega-3 fatty acids (found in

coldwater fish, flax seeds, and walnuts) has

been shown to help in reducing joint

inflammation. Although the usefulness of

omega-3 fatty acids is not as well studied in

Questions and Answers About Ankylosing Spondylitis http://www.niams.nih.gov/Health_Info/Ankylosing_Spondylitis/

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people with ankylosing spondylitis, there is

some evidence that omega-3 supplements

could reduce disease activity in people with

ankylosing spondylitis.

Exercise and stretching, when done carefully

and increased gradually, may help painful, stiff

joints.

Strengthening exercises, performed

with weights or done by tightening

muscles without moving the joints, build

the muscles around painful joints to

better support them. Exercises that

don’t require joint movement can be

done even when your joints are painful

and inflamed.

Range-of-motion exercises improve

movement and flexibility and reduce

stiffness in the affected joint. If the

spine is painful and/or inflamed,

exercises to stretch and extend the

back can be helpful in preventing

long-term disability.

Many people with ankylosing spondylitis find it

helpful to exercise in water.

Before beginning an exercise program, it’s

important to speak with a health professional

who can recommend appropriate exercises.

When Might Surgery Be Necessary,

and How Can It Help?

If ankylosing spondylitis causes severe joint

damage that makes it difficult to do your daily

activities, total joint replacement may be an

option. This involves removing the damaged

joint and replacing it with a prosthesis made of

metals, plastics, and/or ceramic materials. The

most commonly replaced joints are the knee

and hip.

In very rare cases, a procedure called

osteotomy may be used to straighten a spine

that has fused into a curved-forward position.

This surgery involves cutting through the spine

so that it can be realigned to a more vertical

position. After the bones are realigned,

hardware may be implanted to hold them in

their new position while the spine heals.

Surgery to straighten the spine can only be

done by a surgeon with significant experience

in the procedure. Many doctors and surgeons

consider the procedure high risk. This

procedure is done more commonly in Europe

than in the United States.

Questions and Answers About Ankylosing Spondylitis http://www.niams.nih.gov/Health_Info/Ankylosing_Spondylitis/

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What Are Some Things I Can Do to

Help Myself?

Aside from seeing your doctor regularly and

following your prescribed treatment plan,

staying active is probably the best thing you

can do for ankylosing spondylitis. Regular

exercise can help relieve pain, improve

posture, and maintain flexibility. Before

beginning an exercise program, speak with

your doctor or physical therapist about

designing a program that’s right for you.

Another important thing you can do for yourself

is to practice good posture. A good test for

posture is to check yourself in a mirror. First,

stand with a full-length mirror to your side and,

if possible, turn your head to look at your

profile. Next, imagine you have dropped a

weighted string from the top of your head to

the soles of your feet. Where does the string

fall? If your posture is good, it should pass

through your earlobe, the front of your

shoulder, the center of your hip, behind your

kneecap, and in front of your anklebone. If you

are not standing that way already, practice

holding your body that way in front of a mirror

until you know well how it feels. Practicing

good posture can help you avoid some of the

complications that can occur with ankylosing

spondylitis.

What Is the Prognosis for People

With Ankylosing Spondylitis?

The course of ankylosing spondylitis varies

from person to person. Some people will have

only mild episodes of back pain that come and

go, while others will have chronic severe back

pain. In almost all cases, the condition is

characterized by acute, painful episodes and

remissions, or periods of time where the pain

lessens.

In the sacroiliac joints and spine, inflammation

can cause pain and stiffness. Over time, bony

outgrowths called syndesmophytes can

develop that cause the vertebrae to grow

together, or fuse. Fusion can also stiffen the rib

cage, resulting in restricted lung capacity and

restricted lung function.

A number of factors are associated with an

ankylosing spondylitis prognosis. One study

found that among people who had ankylosing

spondylitis for at least 20 years, those who had

physically demanding jobs, other health

problems, or smoked had greater functional

Questions and Answers About Ankylosing Spondylitis http://www.niams.nih.gov/Health_Info/Ankylosing_Spondylitis/

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limitations from their disease. People with

higher levels of education and a history of

ankylosing spondylitis in the family tended to

have less severe limitations from their disease.

A recent study supported by the NIAMS found

that the likelihood of having severe joint

damage increased with age at disease onset,

and that men were twice as likely as women to

be in that group. The study also found that

current smokers were more than four times as

likely to have severe damage as nonsmokers,

and that having a genetic marker called

DRB1*0801 seemed to protect against severe

spine damage.

What Research Is Being Conducted

on Ankylosing Spondylitis?

In addition to the studies mentioned above,

research has focused on finding the additional

genes involved in the development of

ankylosing spondylitis. In 2007, a large

comprehensive genome-wide association scan

led to the discovery of the genes ARTS1 and

IL23R, which is bringing the scientific

community closer to understanding ankylosing

spondylitis. In addition, a 2010 study reported

four genetic regions associated with

ankylosing spondylitis risk, two of which

encode for proteins that may play a role in

ankylosing spondylitis susceptibility.

The IL23R gene plays a role in the immune

system’s response to infection. ERAP1

(previously known as ARTS1) is involved in

processing proteins in the cell into small

“chunks” that can be seen—and fought—by

the body’s immune system. Researchers

believe the discovery could eventually lead to

an understanding of the pathways that are

involved in ankylosing spondylitis, and ways

for doctors to inhibit or strengthen those

pathways to better treat ankylosing spondylitis.

In the near future, the finding could lead to a

blood test to predict ankylosing spondylitis risk

or aid in early diagnosis.

Researchers are also investigating a small

DNA marker that makes it easier and less

expensive to screen for the HLA-B27 gene.

This marker may also provide insights into how

ERAP1 and HLA-B27 interact, contributing to

the development of ankylosing spondylitis.

Scientists are also developing methods to

quantify the progression of spinal fusion in

patients with the disorder and are examining

whether some of the newer drug therapies can

Questions and Answers About Ankylosing Spondylitis http://www.niams.nih.gov/Health_Info/Ankylosing_Spondylitis/

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stop its progression. In the meantime,

medication treatment and exercise are

important for relieving the symptoms and

enabling people to live well with the disorder.

Information on research is available from the

following resources:

NIH Clinical Research Trials and

You helps people learn more about

clinical trials, why they matter, and how

to participate. Visitors to the website

will find information about the basics of

participating in a clinical trial, first-hand

stories from actual clinical trial

volunteers, explanations from

researchers, and links to how to search

for a trial or enroll in a researchmatching program.

ClinicalTrials.gov offers up-to-date

information for locating federally and

privately supported clinical trials for a

wide range of diseases and conditions.

NIH RePORTER is an electronic tool

that allows users to search a repository

of both intramural and extramural

NIH-funded research projects from the

past 25 years and access publications

(since 1985) and patents resulting from

NIH funding.

PubMed is a free service of the U.S.

National Library of Medicine that lets

you search millions of journal citations

and abstracts in the fields of medicine,

nursing, dentistry, veterinary medicine,

the health care system, and preclinical

sciences.

Where Can People Find More

Information About Ankylosing

Spondylitis?

National Institute of Arthritis and

Musculoskeletal and Skin Diseases

(NIAMS)

Information Clearinghouse

National Institutes of Health

1 AMS Circle

Bethesda, MD 20892-0001

Phone: 301-495-4484

Toll Free: 877-22-NIAMS (877-226-4267)

TTY: 301-565-2966

Fax: 301-718-6366

Email: NIAMSinfo@mail.nih.gov

Website: http://www.niams.nih.gov

Other Resources

Questions and Answers About Ankylosing Spondylitis http://www.niams.nih.gov/Health_Info/Ankylosing_Spondylitis/

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American College of Rheumatology

Website: http://www.rheumatology.org

Arthritis Foundation (AF)

Website: http://www.arthritis.org

Spondylitis Association of America (SAA)

Website: http://www.spondylitis.org

For additional contact information, visit the

NIAMS website or call the NIAMS Information

Clearinghouse.

Key Words

Biologics. A relatively new class of

medications that are genetically engineered to

block a protein involved in the body’s

inflammatory response. Four biologics are

approved by the FDA for treating ankylosing

spondylitis. They work by blocking a protein

called tumor necrosis factor-alpha (TNF-α) that

helps drive inflammation.

Calcification. A process in which tissue

becomes hardened as a result of calcium

deposits. In ankylosing spondylitis, calcification

in tissues around the spine can lead to loss of

flexibility and forward curvature.

Corticosteroids. Powerful anti-inflammatory

hormones made naturally in the body or

manmade for use as medicine. In people with

ankylosing spondylitis, corticosteroids may be

injected to temporarily reduce inflammation

and relieve pain.

COX-2 inhibitors. A relatively new class of

nonsteroidal anti-inflammatory drugs (NSAIDs)

that are formulated to relieve pain and

inflammation. Currently, there is just one

COX-2 inhibitor on the market: celecoxib.

Gastroenterologist. A medical doctor who

specializes in diagnosing and treating diseases

of the digestive tract.

Ligaments. Tough bands of connective tissue

that attach bones to each other, providing

stability.

Magnetic resonance imaging (MRI). A

procedure that provides high-resolution

computerized images of internal body tissues.

MRI uses a strong magnet that passes a force

through the body to create these images.

Nonsteroidal anti-inflammatory drugs

(NSAIDs). A class of medications available

Questions and Answers About Ankylosing Spondylitis http://www.niams.nih.gov/Health_Info/Ankylosing_Spondylitis/

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over the counter or with a prescription that

ease pain and inflammation. Commonly used

NSAIDs include aspirin, ibuprofen, and

naproxen sodium.

Ophthalmologist. A medical doctor

specializing in diagnosing and treating

diseases of the eye.

Omega-3 fatty acids. A type of fatty acid

found in fish and fish oils. Omega-3s have

proven beneficial for decreasing inflammation

and reducing the risk of cardiovascular

disease in some people.

Osteotomy. A surgical procedure that

involves cutting a bone to shorten it, lengthen

it, or realign it. In rare cases, the bones of the

spine may be cut and realigned to help

straighten a spine that has fused in a curvedforward position due to ankylosing spondylitis.

Physiatrist. A medical doctor who specializes

in nonsurgical treatment for injuries and

illnesses that affect movement. Also called

rehabilitation physician or rehabilitation

medicine specialist.

Rheumatologist. A medical doctor who

specializes in arthritis and other diseases of

the bones, joints, and muscles.

Syndesmophyte. A bony growth attached to

a ligament. Syndesmophytes between

adjacent vertebrae in ankylosing spondylitis

can cause the vertebrae to grow together, or

fuse.

Tendons. Tough, fibrous cords that connect

muscles to bones.

X ray. A procedure in which low-level radiation

is passed through the body to produce a

picture called a radiograph. X rays showing

damage to the sacroiliac joints are used to

help diagnose ankylosing spondylitis.

Acknowledgments

The NIAMS gratefully acknowledges the

assistance of the following individuals in the

preparation and review of the original version

of this booklet: Robert Colbert, M.D., Ph.D.;

Lori Guthrie, R.N.-B.C., B.S.N., C.C.R.C.; and

Michael Ward, M.D.; NIAMS/NIH; and Laurie

M. Savage, Executive Director, Spondylitis

Association of America, Van Nuys, CA.

The mission of the National Institute of Arthritis

and Musculoskeletal and Skin Diseases

Questions and Answers About Ankylosing Spondylitis http://www.niams.nih.gov/Health_Info/Ankylosing_Spondylitis/

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(NIAMS), a part of the U.S. Department of

Health and Human Services’ National Institutes

of Health (NIH), is to support research into the

causes, treatment, and prevention of arthritis

and musculoskeletal and skin diseases; the

training of basic and clinical scientists to carry

out this research; and the dissemination of

information on research progress in these

diseases. The NIAMS Information

Clearinghouse is a public service sponsored

by the NIAMS that provides health information

and information sources. Additional information

can be found on the NIAMS website at

www.niams.nih.gov. Information on bone and

its disorders can be obtained from the NIH

Osteoporosis and Related Bone Diseases ~

National Resource Center by calling toll free at

800–624–BONE (2663) or by visiting its

website at www.bones.nih.gov.

For Your Information

This publication contains information about

medications used to treat the health condition

discussed here. When this publication was

developed, we included the most up-to-date

(accurate) information available. Occasionally,

new information on medication is released.

For updates and for any questions about any

medications you are taking, please contact

U.S. Food and Drug Administration

Toll Free: 888–INFO–FDA

(888–463–6332)

Website: http://www.fda.gov

For additional information on specific

medications, visit Drugs@FDA at

www.accessdata.fda.gov/scripts

/cder/drugsatfda. Drugs@FDA is a

searchable catalog of FDA-approved

drug products.

For updates and questions about statistics,

please contact

Centers for Disease Control and

Prevention’s National Center for

Health Statistics

Website: http://www.cdc.gov/nchs

This publication is not copyrighted. Readers

are encouraged to duplicate and distribute as

many copies as needed.

Additional copies of this publication are

available from:

Questions and Answers About Ankylosing Spondylitis http://www.niams.nih.gov/Health_Info/Ankylosing_Spondylitis/

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National Institute of Arthritis and

Musculoskeletal and Skin Diseases

(NIAMS)

Information Clearinghouse

National Institutes of Health

1 AMS Circle

Bethesda, MD 20892-0001

Phone: 301-495-4484

Toll Free: 877-22-NIAMS

(877-226-4267)

TTY: 301-565-2966

Fax: 301-718-6366

Email: NIAMSinfo@mail.nih.gov

Website: http://www.niams.nih.gov

NIH Publication No. 10–7609

Many of our publications are

available in print. Would you like to

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our online order form.

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