What is Psoriasis?
Psoriasis is an inflammatory skin condition. There are five types, each with unique signs and symptoms. Between 10% and 30% of people who develop psoriasis get a related form of arthritis called “psoriatic arthritis,” which causes inflammation of the joints.
Plaque psoriasis is the most common type of psoriasis. About 80% of people who develop psoriasis have plaque psoriasis, which appears as patches of raised, reddish skin covered by silvery-white scale. These patches, or plaques, frequently form on the elbows, knees, lower back, and scalp. However, the plaques can occur anywhere on the body.
The other types are guttate psoriasis (small, red spots on the skin), pustular psoriasis (white pustules surrounded by red skin), inverse psoriasis (smooth, red lesions form in skin folds), and erythrodermic psoriasis (widespread redness, severe itching, and pain).
Regardless of type, psoriasis usually causes discomfort. The skin often itches, and it may crack and bleed. In severe cases, the itching and discomfort may keep a person awake at night, and the pain can make everyday tasks difficult.
Psoriasis is a chronic, meaning lifelong, condition because there is currently no cure. People often experience flares and remissions throughout their life. Controlling the signs and symptoms typically requires lifelong therapy.
Treatment depends on the severity and type of psoriasis. Some psoriasis is so mild that the person is unaware of the condition. A few develop such severe psoriasis that lesions cover most of the body and hospitalization is required. These represent the extremes. Most cases of psoriasis fall somewhere in between.
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.
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.
Treatment Advances Improve Outlook
With the emergence of several new therapies, including the biologic agents, more people are experiencing substantial improvements and reporting a greatly improved quality of life.