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1. What causes psoriasis?
The cause is unknown. The skin sheds itself too rapidly, every three
to four days. People often notice new spots 10 to 14 days after
the skin is cut, scratched, rubbed, or severely sunburned. Psoriasis
can also be activated by infections, such as strep throat, and by
certain medicines. Psoriasis cannot be passed from one person to
another, though it is more likely to occur in people whose family
members have it. In the United States two out of every one hundred
people have psoriasis (four to five million people). Approximately
150,000 new cases occur each year.
2. What types of psoriasis
are there?
Psoriasis comes in many forms. Each differs in degree of severity,
how long it lasts, where it is, and in the shape and pattern of
the scales. The most common form begins with little red bumps. These
gradually grow larger and scales form on top of the bumps. These
small red areas then grow, sometimes becoming quite large.
Elbows, knees, groin and genitals, arms, legs, scalp,
and nails are the areas most commonly affected. Psoriasis will often
appear in the same place on both sides of the body.
Psoriatic nails may have tiny pits on them. Nails
may loosen, thicken or crumble.
Inverse (reverse pattern) psoriasis occurs in the
armpit, under the breast and in skin folds around the groin, buttocks,
and genitals.
Guttate psoriasis usually affects children and young
adults. It often shows up after a sore throat, with many small,
red, teardrop-like, scaly spots appearing on the skin.
About seven percent of psoriasis patients have arthritis,
which fortunately is not too severe in most people. The arthritis
may be worst when the skin is very involved and may improve when
the condition of the patient's skin improves.
3. How is Psoriasis
Diagnosed?
Dermatologists diagnose psoriasis by examining the skin, nails,
and scalp. A skin biopsy may be needed to confirm the diagnosis.
4. How Is Psoriasis Treated?
The goal of therapy is to reduce inflammation and to slow down rapid
skin cell division. Sunlight exposure helps the majority of people
with psoriasis.
There are several effective treatments for psoriasis.
Topical steroids (Cortisone) may clear the skin temporarily and
control the condition in many patients. These must be used cautiously
since side effects of the stronger cortisone preparations include
thinning of the skin, dilated blood vessels, bruising, and skin
color changes. After many months of treatment, the psoriasis may
become resistant to the steroid preparations. Anthralin is a tar
based medication that works well as a long term treatment on tough-to-treat
thick patches of psoriasis. It can cause irritation and temporary
staining of the skin and clothes. For more than 100 years, coal
tar has been used to treat psoriasis. Today's products are greatly
improved and less messy. Stronger prescriptions can be made to treat
difficult areas. A synthetic Vitamin D, calcipotriene, is now available
in prescription form. It is useful for individuals with localized
psoriasis and can be used with other treatments. When psoriasis
has not responded to other treatments or is widespread, PUVA is
effective in 85 to 90 percent of cases. Patients are given a drug
called psoralen, then are exposed to a carefully measured amount
of a special form of ultraviolet (UVA) light. Because psoralen remains
in the lens of the eye for 24 hours, patients must wear UVA blocking
eyeglasses. Methotrexate is an oral anti-cancer drug that can produce
dramatic clearing of psoriasis when other treatments have failed.
Because it can produce liver disease, regular blood tests are performed
and liver biopsies may be required. Prescription Vitamin A drugs
known as retinoids may be used alone or in combination with ultraviolet
light for severe cases of psoriasis. Side effects include dryness
of the skin, lips and eyes, elevation of fat levels in the blood,
and formation of tiny bone spurs. Retinoids should not be used by
women of child-bearing age, as birth defects may result. Special
diets have not been successful in treating psoriasis.
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