Psoriasis is a common skin condition where the skin develops areas that become
thick covered with silvery scales. It is a common problem, and millions of
people in the United States have psoriasis. The course of psoriasis is quite
variable, but in most sufferers it is a chronic problem that continues for
years. The presence of psoriasis can cause emotional distress.
There are several ways psoriasis can start. In most sufferers, the tendency to
get psoriasis is inherited. It is not passed on in a simple, direct way like
hair color, but involves multiple genes. For this reason, it is not always clear
from whom one inherited it. Inherited psoriasis usually starts in older
childhood or as a young adult. Sometimes, especially in children, a virus or
strep throat triggers brief attacks of tiny spots of psoriasis.
In middle-aged older adults, a non-hereditary type of psoriasis can develop. This
changes more rapidly than the inherited form, varying in how much skin is
involved more unpredictably. Most types of psoriasis show some tendency to come
and go, with variable intensity over time.
Psoriasis flare-ups may be triggered by changes in climate, infections, stress,
excess alcohol, a drug-related rash and dry skin.
Medications may trigger a flare up weeks to months after starting them. These include non-steroidal
anti-inflammatory drugs (Indocin, Advil, Feldene, others), blood pressure
(beta-blockers such as Tenormin, Inderal), oral steroids such as prednisone, or
Psoriasis tends to be worst in those with a disordered immune system for other
reasons (cancer, AIDS or autoimmune disease). Psoriasis areas are worsened by
scratching and minor skin injuries or irritations. Psoriasis may itch or burn.
It most often occurs over the elbows, knees, scalp, lower back, and palms or
soles of the feet. The skin may split or crack in areas that bend.
There are several forms of psoriasis. The most common form shows reddened areas a
few inches across covered by silvery scales. Dermatologists refer to the
affected areas as areas as "plaques". Other patterns psoriasis can appear in are
"inverse" (shiny, red patches in areas of friction such as in the folds of skin
in the groin, the armpits or under the breasts), pustular (blisters of
noninfectious pus on red skin), or "erythrodermic" (reddening and scaling of
most of the skin).
Psoriasis may also affect some of the joints causing discomfort and restricted
motion, and even distortion. This occurs in about 10 percent of people with
psoriasis. This is called "psoriatic arthritis". It often affects only a few
fingertips, but in some it can be severe and widespread. It also may affect the
fingernails, toenails and the mucous membranes lining the genitalia and mouth.
Treatment is based on the severity of the disease and it's responsiveness to
prior treatments. The lowest level of treatment is topical medicine are applied
to the skin, the next level involves treatments with ultraviolet light
(phototherapy) and finally, taking medicines internally. Treatments from each
level are often combined, or switched around every 12 to 24 months to reduce
resistance and adverse reactions.
A treatment that is effective in one person may fail in another. Both
trial-and-error and personal preferences often guide treatment. Over time,
psoriasis tends to resist its treatments. The locations, size and amount of
psoriasis, prior treatments, and the specific form of the disorder are factored
into treatment decisions.