Psoriasis including plaque psoriasis, guttate psoriasis, pustular psoriasis,
nail psoriasis, inverse psoriasis, methotrexate psoriasis, psoriasis penis
causes
No one knows exactly what causes
psoriasis.
However, it is understood that the immune system and genetics
play major roles in its development. Most researchers agree that
the immune system is somehow mistakenly triggered, which causes
a series of events, including acceleration of skin cell growth.
A normal skin cell matures and falls off the body in 28 to 30
days. A skin cell in a patient with psoriasis takes only 3 to 4
days to mature and instead of falling off (shedding), the cells
pile up on the surface of the skin, forming psoriasis lesions.
Scientists believe that at least 10 percent
of the general population inherits one or more of the genes that
create a predisposition to
psoriasis. However, only 2 percent to
3 percent of the population develops the disease. Researchers
believe that for a person to develop
psoriasis, the individual
must have a combination of the genes that cause
psoriasis and be
exposed to specific external factors known as “triggers.”
Learn more about genetic
and immune system involvement in
psoriasis and psoriatic
arthritis.
Psoriasis triggers are not universal. What
may cause one person’s
psoriasis to become active, may not
affect another. Established
psoriasis triggers include:
Stress
Stress can cause
psoriasis to flare for the
first time or aggravate existing psoriasis. Relaxation
and stress reduction may help prevent stress from impacting
psoriasis.
Injury to skin
Psoriasis can appear in areas of the skin
that have been injured or traumatized. This is called the Koebner [KEB-ner] phenomenon. Vaccinations, sunburns and
scratches can all trigger a Koebner response. The Koebner
response can be treated if it is caught early enough.
Medications
Certain medications are associated with
triggering
psoriasis, including:
-
Lithium: Used to treat manic depression
and other psychiatric disorders. Lithium aggravates
psoriasis in about half of those with psoriasis who take it.
-
Antimalarials: Plaquenil, Quinacrine,
chloroquine and hydroxychloroquine may cause a flare of
psoriasis, usually 2 to 3 weeks after the drug is taken. Hydroxychloroquine has the lowest incidence of side effects.
-
Inderal: This high blood pressure
medication worsens
psoriasis in about 25 percent to 30
percent of patients with
psoriasis who take it. It is not
known if all high blood pressure (beta blocker) medications
worsen
psoriasis, but they may have that potential.
-
Quinidine: This heart medication has been
reported to worsen some cases of
psoriasis.
-
Indomethacin: This is a nonsteroidal
anti-inflammatory drug used to treat arthritis. It has
worsened some cases of
psoriasis. Other anti-inflammatories
usually can be substituted. Indomethacin's negative effects
are usually minimal when it is taken properly. Its side
effects are usually outweighed by its benefits in psoriatic
arthritis.
Other triggers
Although scientifically unproven, some people
with
psoriasis suspect that allergies, diet and weather trigger
their psoriasis. Strep infection is known to trigger guttate
psoriasis.
