If you have psoriasis, you may develop a form of arthritis associated with
your skin disease. It is important to determine whether you have psoriatic
arthritis in order to avoid joint damage that could affect your quality
of life. Fortunately psoriatic arthritis is treatable.
Fast Facts
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People with psoriasis may develop this type of arthritis.
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New treatments are now available for psoriasis and psoriatic arthritis.
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It is important to remain physically active to preserve joint motion.
What psoriatic arthritis is
Psoriatic arthritis is a form of arthritis associated with psoriasis,
a chronic disease in which scaly red and white patches develop on the
skin. Like rheumatoid arthritis, it results when the body's immune system,
which normally exists to protect against invaders, goes into overdrive
and causes excessive inflammation.
Psoriatic arthritis can affect any joint within the body. When psoriasis
affects fingernails (causing them to be pitted, thickened, or discoloured),
the joints at the end of the fingertips are particularly likely to develop
arthritis. Psoriatic arthritis can also cause a sausage-like swelling
of fingers and toes, a condition known as dactylitis that can be confused
with an infection.
Symptoms of psoriatic arthritis vary in nature and intensity, and may
change in the same person over time. In some people, psoriatic arthritis
affects the same joint on both sides of the body (e.g., both knees). In
others, one joint is affected but not the other (e.g., one knee). Sometimes
only the fingers and toes are affected; the spine may be affected, resulting
in difficulty bending.
Like the skin disease it is associated with, psoriatic arthritis can
cause symptoms that periodically show up, or flare, and then subside.
Although psoriatic arthritis was originally thought to be mild and non-progressive
(that is, that it would not worsen over time), recent data suggest that
many of those affected will experience persistent inflammation and need
treatment to prevent joint damage that can affect your ability to get
day to day things done. Fortunately treatments are available and effective
for most people.
Occasionally a condition known as spondylitis—involving pain in the back
or neck—develops as a result of psoriatic arthritis. Another condition
that may develop is enthesopathy, characterized by tender spots at sites
in the body where tendons and ligaments join bones. This can cause symptoms such as
pain at the back of the heel or in the sole of the foot.
What causes psoriatic arthritis
The exact cause of psoriatic arthritis is unknown, but researchers suspect
that the disorder develops because of a combination of genetic (hereditary)
and environmental (external) factors. As many as 40 percent of people
with psoriatic arthritis have a family history of psoriasis or arthritis,
indicating that they are prone to develop arthritis because of their genetic
makeup, especially when their immune system is stimulated by an environmental
trigger such as an infection. (Psoriasis itself is not infectious, but
occasionally it can be triggered by a streptococcal throat infection.)
Who gets psoriatic arthritis
Psoriatic arthritis usually develops between ages 30 to 50, but can begin
in childhood. Men and women are equally at risk.
Only about 15 percent of people with psoriasis develop psoriatic arthritis.
At times, the arthritis can develop before the onset of the skin disorder.
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| Psoriatic arthritis typically affects the large joints, especially those of the lower extremities,
distal joints of the fingers and toes, and can also affect the back and sacroiliac joints of the pelvis. |
|
How psoriatic arthritis is diagnosed
Diagnosis of psoriatic arthritis is made on the basis of the disorder's
characteristic clinical features. Joints may be swollen and painful. Before
a precise diagnosis can be made, skin and nail changes typical of psoriasis
must be demonstrated, and occasionally skin biopsies (small samples of skin
removed for analysis) are performed. Blood tests from some patients will
reveal elevated erythrocyte sedimentation rate (ESR) (a blood test that
measures inflammation), mild anemia, and elevated levels of uric acid. Other
types of arthritis that cause similar signs and symptoms, such as
gout and
rheumatoid arthritis, must be
ruled out.
How psoriatic arthritis is treated
Unlike rheumatoid arthritis, which usually requires constant treatment, psoriatic arthritis may only require therapy when symptoms arise. When they subside, therapy can be stopped until further problems develop.
Initial treatment usually consists of non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen (
Motrin
or Advil) or naproxen (
Naprosyn). If the arthritis does not respond, disease modifying anti-rheumatic drugs (DMARDs) may be used. These include
sulfasalazine (
Azulfidine),
methotrexate (
Rheumatrex),
cyclosporine (
Neoral,
Sandimmune) and the more recently available “
anti-TNF
agents” such as etanercept (
Enbrel) and infliximab (
Remicade) and adalimumab (
Humira).
The anti-malarial drug
hydroxychloroquine (
Plaquenil) may be effective, but some people taking this will experience a flare of their psoriasis, so it is usually avoided.
Azathioprine (
Imuran) may benefit those with severe forms of psoriatic arthritis. For severely swollen joints, corticosteroid injections can be useful at controlling the inflammation. Surgery can be helpful to repair or replace badly damaged joints.
Broader heatlh impact of psoriatic arthritis
The impact of psoriatic arthritis depends on the joints involved and the severity of symptoms. Fatigue and anemia are common. Some psoriatic arthritis patients have changes in mood.
Living with psoriatic arthritis
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Many people with arthritis develop stiff joints and muscle weakness due
to lack of use, so proper exercise is very important, as it will improve
overall health and keep joints flexible. |
Many people with arthritis develop stiff joints and muscle weakness due
to lack of use, so proper exercise is very important, as it will improve
overall health and keep joints flexible. This does not need to be excessive.
Taking a walk is an excellent way to get exercise. If your feet, ankles,
or knees are affected by arthritis, you may need a walking aid or shoe
inserts to avoid putting undue stress on your lower joints. A physical
therapist can provide advice. Some people with arthritis find it easier
to move in water. If this is the case, swim or walk laps in the pool to
enjoy activity without stressing joints. An exercise bike provides another
low-impact option. Yoga and stretching exercises may help you to relax.
Many people with psoriatic arthritis benefit from physical and occupational
therapy to strengthen muscles, protect joints from further damage, and
increase flexibility.
Points to Remember
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Psoriatic arthritis is a chronic arthritis
and in some people it is mild and comes and goes, in other people
it can cause a persistent arthritis that can cause joint damage if
it is not treated.
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For most people, appropriate treatments will
relieve pain, protect the joints, and maintain mobility.
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Psoriatic arthritis is sometimes misdiagnosed as gout or can be associated
with gout.
The rheumatologist's role in the treatment
of psoriatic arthritis
Psoriatic arthritis is easy to confuse with other diseases. Rheumatologists
are specialists in musculoskeletal disorders and therefore are more likely
to make a proper diagnosis. They can also advise patients about the best
treatment options available.
To find a rheumatologist
For more information about rheumatologists, click
here.
For a listing of rheumatologists in your area, click
here.
For more information
The American College of Rheumatology has compiled this list to give you
a starting point for your own additional research. The ACR does not endorse
or maintain these Websites, and is not responsible for any information
or claims provided on them. It is always best to talk with your rheumatologist
for more information and before making any decisions about your care.
The Arthritis Foundation
www.arthritis.org
The Psoriasis Foundation
www.psoriasis.org
Psoriasis Information Program (English and French)
www.psoriasisinfo.ca
National Institute of Arthritis and Musculoskeletal and Skin Diseases
Information Clearinghouse
www.niams.nih.gov
Updated May 2004
Written by Paul Emery, MD, and reviewed by the American College of Rheumatology
Communications and Marketing Committee.
