What's the connection between psoriasis and psoriatic arthritis? Both are
thought to be caused primarily by your immune system. But not everyone who has
psoriasis -- which causes patches or plaques of scaly and inflamed skin --
develops psoriatic arthritis. This form of inflammatory arthritis causes joint
swelling and pain, and may lead to permanent deformity and damage if not
Some of the most common psoriatic arthritis symptoms include:
Painful, swollen joints: Psoriatic arthritis can be symmetrical (meaning it
affects the same joints on both sides of the body) or asymmetrical. With
asymmetrical psoriatic arthritis, your left fingers and right toes might be
affected, for example.
Sausage-like swelling of fingers and toes
Nail changes: Psoriatic arthritis often affects the joints closest to the
nail bed. It can cause pitting or ridging of the nails or nails that peel away
from the fingers and toes.
Back and neck pain: For about 5% of people with psoriatic arthritis, the
main symptom is an inflamed spinal column, which makes movement very difficult.
Stiffness, especially after sitting or sleeping
How Psoriasis and Psoriatic Arthritis Are Connected
About 30% of people who have psoriasis will develop psoriatic arthritis. In
most cases, the skin symptoms of psoriasis appear before psoriatic arthritis
develops. It is possible, however, for psoriatic arthritis symptoms to appear
months, or even years, before any skin lesions develop.
Both psoriasis and psoriatic arthritis are thought to be caused by primarily
by your immune system. In the case of your skin, this causes cells to grow too
quickly without sloughing off. Layers of skin build up, resulting in the skin
plaques of psoriasis. With psoriatic arthritis, the immune system targets
joints and connective tissue, causing destructive, painful, swollen joints.
There does not seem to be a connection between where the scaly skin patches
from psoriasis are located and which joints are affected by psoriatic
arthritis. For example, you could have skin lesions on both your elbows, but
your elbow joints could be unaffected by psoriatic arthritis. In the same way,
psoriatic arthritis could cause sausage-like swelling of the toes without any
redness or scaling on the feet.
Psoriasis skin lesions can flare up and then subside, and psoriatic
arthritis symptoms may also wax and wane. But while psoriasis does not cause
scarring or any other permanent damage to the skin, psoriatic arthritis can
cause permanent deformity and damage to the joints if not treated. That's why
it is very important to work with your doctor even if your psoriatic arthritis
symptoms subside. Don't taper your medications without talking to your doctor
Both psoriasis and psoriatic arthritis seem to have a strong genetic
component. About 40% of people who develop psoriatic arthritis have relatives
with either psoriasis or psoriatic arthritis. Family members of people with
psoriatic arthritis are 55 times more likely to develop the disease than those
without a family history of the disease. While scientists don't yet know which
genes are responsible for psoriasis and psoriatic arthritis, research is
underway to find genetic markers. Discovering which genes are involved in
psoriatic arthritis may help scientists develop future treatments.
Genetics aren't the sole factor in determining whether someone develops
psoriasis and psoriatic arthritis; environmental factors are also believed to
be very important.