Psoriasis
What is it?
Psoriasis is a chronic disease of the skin that is
characterized by silvery, scaly raised patches of dead
skin.
Who gets it?
Psoriasis is a common skin disease that is more likely
to occur in fair-skinned people. It can occur at any age,
but most often appears between the ages of 10 and 40.
People at higher risk for developing psoriasis are those
with a family history of the disease, those on steroid
medications, and those with high stress levels. Psoriasis
can also flare up after an injury, during an illness or
infection, and after exposure to extremely cold
temperatures.
What causes it?
People with psoriasis have an abnormally high rate of
skin cell maturity. The skin cells mature so rapidly (in
less than one week compared with the normal rate of every
28 to 30 days) that the body is unable to shed old cells
quickly enough for the new cells to replace them. As the
new cells push their way to the surface of the skin, the
old cells create a build up of dead skin, which appear as
raised patches. Researchers aren’t sure what causes this
rapid cell growth, but suspect it is related to a
malfunction in the immune system.
What are the symptoms?
Psoriasis usually affects the elbows, knees, back,
scalp, and buttocks, but can occur on any part of the
body, including the fingernails. In its most common form,
psoriasis begins as small, raised patches, called plaques,
that grow larger and become inflamed. The inflamed skin
gets scaly and flakes off, like dandruff. However, the
scales underneath cause bleeding if removed. The plaques
may or may not itch. Mild psoriasis affects less than 5%
of the skin. Psoriasis is considered severe when it
affects more than 30% of the skin. A small percentage of
psoriasis patients develop an inflammation of the joints
called psoriatic arthritis. Psoriatic arthritis usually
affects the joints of the fingers and toes, causing pain
and swelling. Joint symptoms may follow a flare-up of
psoriasis, and the two may come and go together. Some
patients also experience joint pain in the hips and spine,
and develop conjunctivitis (pink eye). Symptoms may affect
joints on only one side of the body, or on both sides at
the same time. The fingernails may also undergo changes,
becoming thickened and pitted.
How is it diagnosed?
Psoriasis is diagnosed through a physical examination
and a complete medical history. A diagnosis of psoriatic
arthritis is usually made when psoriasis is accompanied by
symptoms of arthritis. Your doctor will review your
symptoms, carefully examine your skin and nails for
indications of psoriasis, and ask about any personal or
family history of this skin condition. He or she will also
order a blood test to check for the antibodies that
indicate rheumatoid arthritis.
What is the treatment?
Treatment of psoriasis depends upon the severity of
your symptoms. Mild to moderate psoriasis is treated with
steroid creams and ointments, vitamin A-derived topical
treatments, and ointments containing salicylic acid or
coal tar. Moderate cases often respond to a combination of
medication and exposure to UVB light (phototherapy)
administered under medical supervision. Another type of
phototherapy called photochemotherapy uses UVA light (PUVA)
to relieve the symptoms of moderate psoriasis, as well as
the joint inflammation of psoriatic arthritis. Your doctor
must closely supervise this type of treatment. Keep in
mind that sunburn can make psoriasis symptoms worse.
Severe psoriasis and psoriatic arthritis are treated with
a drug called methotrexate (MTX), which suppresses the
immune system. MX carries a risk of damage to the liver,
kidneys, and bone marrow, so it must be taken under
careful medical supervision. Drugs containing the vitamin
A-derived etrentinate or isotretinoin, used to treat
severe acne, may also be prescribed, but they too carry
risks of side effects. Pregnant women and women who are
planning to become pregnant within one year should not
take these drugs because they remain in the body for a
long time and can cause birth defects. Cyclosporin
emulsion and laser therapy are other possible treatments
for severe psoriasis. Some doctors believe that food
allergies and intolerances play a role in autoimmune
disorders. An allergist can help you determine if you have
any food allergies that could be triggering your
condition. Other alternative treatments include
constitutional homeopathy, acupuncture, herbal medicine,
and nutritional supplements. Your doctor can help you
explore these types of treatments and determine if they
are right for you.
Self-care tips
While psoriasis can be a nuisance, psoriasis does not
usually interfere with a normal lifestyle. While there is
no known way to prevent psoriasis or psoriatic arthritis,
following your doctor’s treatment recommendations can help
reduce and relieve symptoms.
This information has been designed as a comprehensive and quick reference
guide written by our health care reviewers. The health information written
by our authors is intended to be a supplement to the care provided by your
physician. It is not intended nor implied to be a substitute for
professional medical advice.
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