Effects do not always stop with the skin.

• Position: Psoriasis - Disease/Disorder overview

Psoriasis, a chronic condition that causes red, raised patches of skin, is seen increasingly as a systemic disease with links to arthritis and cardiovascular disease. Dermatologists from the Mayo Clinic, Rochester, Minn., provide an overview of this sometimes embarrassing condition, what is known about it, and how it is treated:

Symptoms. Patches of thick, red skin covered with silvery, flaky scales commonly appear on the elbows and knees, but can emerge anywhere on the body. They result from skin cells in overdrive, reproducing much faster than normal. Physicians are not certain why this overproduction occurs, although genetic and environmental factors likely play roles. Psoriasis symptoms come and go and flare in response to triggers that can include infections, some medications, alcohol, smoking, stress, sunburn, skin irritation, or injury.

A systemic illness. Doctors are finding that psoriasis is more than a skin disorder. About one in four people with the condition develop a form of arthritis called psoriatic arthritis that can cause pain, stiffness, and swelling of the joints. Studies have shown that individuals with psoriasis face a higher risk of heart attack, stroke, and other cardiovascular complications. The underlying link may be chronic inflammation, which plays a role in psoriasis and heart disease.

Treatment. While psoriasis cannot be cured, a variety of topical...