Psoriasis is a chronic (long-lasting) skin disease of scaling and inflammation that affects 2 to 2.6 percent of the
United States population, or between 5.8 and 7.5 million people. Although the disease occurs in all age groups, it
primarily affects adults. It appears about equally in males and females. Psoriasis occurs when skin cells quickly rise
from their origin below the surface of the skin and pile up on the surface before they have a chance to mature.
Usually
this movement (also called turnover) takes about a month, but in psoriasis it may occur in only a few days. In its
typical form, psoriasis results in patches of thick, red (inflamed) skin covered with silvery scales. These patches,
which are sometimes referred to as plaques, usually itch or feel sore. They most often occur on the elbows, knees,
other parts of the legs, scalp, lower back, face, palms, and soles of the feet, but they can occur on skin anywhere on
the body.
The disease may also affect the fingernails, the toenails, and the soft tissues of the genitals and inside the mouth.
While it is not unusual for the skin around affected joints to crack, approximately 1 million people with psoriasis
experience joint inflammation that produces symptoms of arthritis. This condition is called psoriatic arthritis.
In psoriasis, an activated immune system triggers the skin to reproduce every three to four days, building up on the
outer layers (epidermis and keratin). The epidermis thickens, blood flow increases and reddens the skin, and silver-
gray scales cover it.
Rarely life-threatening, at its mildest, psoriasis can be itchy and sore. At its worst, it’s painful, disfiguring, and
debilitating. About two-thirds of the people with psoriasis have a mild form of the disease, says the NPF. About one-
third have moderate or severe psoriasis. Psoriasis can affect people at any age, but it most often strikes those
between the ages of 15 and 35.
There are five forms of psoriasis. Plaque psoriasis is the most common–affecting 4 out of 5 people who have psoriasis,
says the NPF. Plaque psoriasis may start with small red bumps and progress to larger lesions.
The plaques of psoriasis occur most frequently on the elbows, knees, other parts of the legs, scalp, back, face, palms,
and soles of the feet. Psoriasis can also affect the fingernails and toenails, causing pitting, discoloration, or
tissue buildup around the nails. According to the National Institute of Arthritis and Musculoskeletal and Skin
Diseases, about 15 percent of people with psoriasis also get psoriatic arthritis, which can be progressively disabling
if untreated.
Who Gets Psoriasis More than 4.5 million adults in the United States have been diagnosed with psoriasis, and
approximately 150,000 new cases are diagnosed each year. An estimated 20% have moderate to severe psoriasis.
Psoriasis occurs about equally in males and females. Recent studies show that there may be an ethnic link. It seems
that psoriasis is most common in Caucasians and slightly less common in African Americans. Worldwide, psoriasis is most
common in Scandinavia and other parts of northern Europe. It appears to be far less common among Asians and is rare in
Native Americans.
There also is a genetic component associated with psoriasis. Approximately one-third of people who develop psoriasis
have at least one family member with the condition.
Research shows that the signs and symptoms of psoriasis usually appear between 15 and 35 years of age. About 75%
develop psoriasis before age 40. However, it is possible to develop psoriasis at any age. After age 40, a peak onset
period occurs between 50 and 60 years of age.
About 1 in 10 people develop psoriasis during childhood, and psoriasis can begin in infancy. The earlier the psoriasis
appears, the more likely it is to be widespread and recurrent.
Psoriatic arthritis develops in roughly one million people across the United States, and 5% to 10% experience some
disability. Psoriatic arthritis usually first appears between 30 and 50 years of age — often months to years after skin
lesions first occur. However, not everyone who develops psoriatic arthritis has psoriasis. About 30% of people who get
psoriatic arthritis never develop the skin condition.
Causes Psoriasis may be one of the oldest recorded skin conditions. It was probably first described around 35 AD. Some
evidence indicates an even earlier date. Yet, until recently, little was known about psoriasis.
While scientists still do not fully know what causes psoriasis, research has significantly advanced our understanding.
One important breakthrough began with the discovery that kidney- transplant recipients who had psoriasis experienced
clearing when taking cyclosporine. Since cyclosporine is a potent immunosuppressive medication, this indicates that the
immune system is involved.
Immune Mediated. Researchers now believe that psoriasis is an immune-mediated condition. This means the condition is
caused by faulty signals in the body’s immune system. It is believed that psoriasis develops when the immune system
tells the body to over-react and accelerate the growth of skin cells. Normally, skin cells mature and are shed from the
skin’s surface every 28 to 30 days. When psoriasis develops, the skin cells mature in 3 to 6 days and move to the skin
surface. Instead of being shed, the skin cells pile up, causing the visible lesions.
Genes. Researchers have identified genes that cause psoriasis. These genes determine how a person’s immune system
reacts. These genes can cause psoriasis or another immune-mediated condition, such as rheumatoid arthritis or type 1
diabetes. The risk of developing psoriasis or another immune-mediated condition, especially diabetes or Crohn’s
disease, increases when a close blood relative has psoriasis.
Family History. Some people who have a family history of psoriasis never develop this condition. Research indicates
that a “trigger” is needed. Stress, skin injuries, a strep infection, certain medications, and sunburn are some of the
known potential triggers. Medications that can trigger psoriasis are anti- malarial drugs, beta-blockers (medication
used to treat high blood pressure and heart conditions), and lithium. Dermatologists have seen psoriasis suddenly
appear after a person takes one of these medications, gets a strep infection, or experiences another trigger.
Psoriasis research continues to accelerate at a rapid pace and will continue to advance our knowledge of what causes
psoriasis.
Quality of Life All types of psoriasis, ranging from mild to severe, can affect a person’s quality of life. Living with
this lifelong condition can be physically and emotionally challenging.
Itching, soreness, and cracked and bleeding skin are common. Nail psoriasis can be painful. Even the simple act of
squeezing a tube of toothpaste can hurt. One woman described her psoriasis as feeling like “a bad sunburn that won’t go
away.”
Several studies have shown that people often feel frustrated. In some cases, psoriasis limits activities and makes it
difficult to perform job responsibilities. The National Psoriasis Foundation reports that 56 million work hours are
lost each year by those who have psoriasis. Additionally, a survey conducted by the National Psoriasis Foundation in
2002 indicates that 26% of people living with moderate to severe psoriasis have been forced to change or discontinue
their normal daily activities.
Studies also have shown that stress, anxiety, loneliness, and low self-esteem are part of daily life for people living
with psoriasis. One study found that thoughts of suicide are three times higher for psoriatics than the general
population.
Embarrassment is another common feeling. Imagine getting your hair cut and noticing that the stylist or barber is
visibly uncomfortable. What if you extended your hand to someone and the person recoiled? How would you feel if you
spent most of your life trying to hide your skin?