What is psoriasis?
Psoriasis is a common skin
disorder that produces thick, pink to red, itchy patches of skin
covered with silvery scales. In black African-Americans, the rash
may be the same color as the skin. The rash usually occurs on the
scalp, elbows, knees, lower back and genitals and in the same place
on both sides of the body. It can also occur in the fingernails.
Psoriasis does not spread from person to person.
Psoriasis usually begins in early adulthood but it can start
later in life. The rash can heal and come back throughout a
person's life. In most people, the rash is limited to a few
patches of skin. In severe cases, it can cover large areas of the
How does the rash start?
Psoriasis starts as small
red bumps. The bumps grow in size and scales form on top. These
surface scales shed easily, but scales below them stick together.
When scratched, the lower scales tear away from the skin, causing
bleeding. As the rash grows large lesions can form. The silvery
scales on top of these lesions are sometimes called "plaques."
What are the symptoms of psoriasis?
As well as the
symptoms described above, the rash may produce:
- Intense itching
- Dry and cracking skin
- Skin swelling
- Skin pain
- Pitted, cracked, or crumbly nails
- Loose nails
Less common forms of psoriasis
Inverse psoriasis--Psoriasis under the armpit and
breast and in skin folds around the groin, buttocks and genitals.
Guttate psoriasis--Small, red, drop-shaped, scaly
spots in children and young adults that often appear after a sore
throat caused by a streptoccocal infection.
Pustular psoriasis--Small pus-filled bumps appear on
the usual red patches or plaques
How can I know if I have psoriasis?
If you have a skin rash that won't go away, contact your
health care provider. He or she can look at the rash to see if it
is psoriasis or another skin condition. Rarely, a small sample of
skin is taken to view under a microscope.
What causes psoriasis?
The cause of psoriasis is
unknown. The condition tends to run in families, so it may be
passed on to children by parents.
Psoriasis causes new skin cells to develop too quickly.
Normally, skin cells are replaced every 28 to 30 days. In
psoriasis, new cells grow and move to the surface of the skin every
three to four days. The build up of old cells being replaced by new
cells creates the hallmark silvery scales of psoriasis.