New Weapons in Fight Against Psoriasis

Several target more severe forms of the skin disease

(HealthDay is the new name for HealthScoutNews.)

FRIDAY, Aug. 29, 2003 (HealthDayNews) -- Life for psoriasis sufferers is about to get easier.

New breakthrough treatments, along with the existing stock of remedies, should mean more satisfactory results for people afflicted with mild and even severe forms of the condition.

"We're not only making a tremendous amount of progress understanding the immunology of psoriasis but also the genetics of psoriasis," says Dr. Paul Cabiran, a dermatologist with the Ochsner Clinic in New Orleans.

"Before, treatments were more generalized, and now they're more specific. They're getting much more sophisticated," Cabiran adds.

That's a message health officials want to communicate during August, which has been designated Psoriasis Awareness Month.

An estimated 5.5 million Americans suffer from psoriasis. And up to 15 percent of people with psoriasis suffer from psoriatic arthritis, an inflammation of the joints that produces arthritis symptoms, according to the National Institute of Arthritis and Musculoskeletal and Skin Diseases.

Psoriasis is marked by an uncomfortable thickening of the skin with bright red patches and silvery scales. But this is just the visible manifestation of what is apparently an immune process gone awry.

Defective immune system cells trigger a cascade of events that results in the skin's outer layer growing at a much faster rate than normal. "In some cases, it's seven or eight times the normal rate of skin growth," Cabiran explains. "The process is accelerated tremendously so the dead layers build up too quickly."

So quickly, that there's not enough time for the old layers to slough off to make room for the new, hence the scaly, thick patches or "plaques." The red color comes from the increased blood supply that rapidly growing cells need to fuel them.

The majority of psoriasis cases seem to have a genetic component, though scientists are still working to find the culprit gene -- or genes.

The relatively recent discovery that psoriasis is an immune-based disease has paved the way for breakthroughs in treatment for more severe forms of the disease.

"That understanding has led people to say, 'Let's see what we can do to have more effective therapy,'" says Dr. Kenneth Gordon, an associate professor of medicine at the Loyola University Stritch School of Medicine in Chicago and chairman of the National Psoriasis Foundation's research committee.

An estimated one-quarter to one-third of people with psoriasis suffer from more severe forms of the disease, measured by how much of their body surface is affected.

Traditionally, these individuals have been treated with high-octane drugs that affect the whole body, not just the area requiring care. One of the most common is methotrexate, a chemotherapy drug most often used against cancer of the lymph system. Another common drug is cyclosporine, which suppresses the immune system and is used to prevent organ rejection in transplant patients.

The problem is that, over the long term, these therapies can increase the risk of cancer and may have adverse affects on the liver, kidney and blood pressure, Gordon says.

"We've been limited and many physicians have felt uncomfortable treating [psoriasis] aggressively," Gordon says. "We have not been making patients very happy because almost half of them want more aggressive therapy and are unsatisfied with therapy they have."

In March, however, the U.S. Food and Drug Administration (FDA) approved the first biologic treatment for psoriasis -- alefacept (brand name Amevive), which is widely considered to be a breakthrough drug.

A study in the June issue of the Archives of Dermatology found that people taking 15 milligrams of alefacept had a 75 percent reduction in their Psoriasis Area and Severity Index (PASI), a measure of the clinical severity of the condition. Alefacept halts the overproduction of skin cells by destroying the defective immune cells that are responsible.

"These biologic medications are designed to attack a very specific part of the immune system and leave the rest of the body intact," Gordon says. "The true benefit of these medications, we think, is this ability to use them with a high level of security about safety for long periods of time.

"Many patients get psoriasis when they're young. What you have is a situation where people are going to have a disease for 30, 40, 50 years so long-term safety is paramount," he adds.

Another biologic drug, Enbrel, or etanercept, has also been approved by the FDA for psoriatic arthritis.

For milder forms of the disease, different treatments are available.

"Topical therapies [creams] are more reasonable with people with less body area involved because it takes less time to cover themselves with creams every day," Gordon says.

Cabiran says steroid creams and topical Vitamin D are a common first step for people who simply have a little patch on the elbow or knees or scalp.

People with larger areas affected might benefit from phototherapy -- light therapy.

"One of the most successful types is narrow-band UVB, which is a very specific wave length of UVB light," Cabiran says. "You turn the light on for a few minutes. It's a really great way to treat the whole body. Can you use the light with topical steroids or vitamin D? Yes, that's perfectly reasonable."

More information

To learn more about psoriasis and treatments, visit the National Institute of Arthritis and Musculoskeletal and Skin Diseases or the National Psoriasis Foundation.

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