Want to know more about psoriasis and what you can do about it?
We asked the National Institute of Arthritis and Musculoskeletal and Skin Diseases for answers to basic questions.
We Know: 1-Minute Lesson on Psoriasis
What is psoriasis?
Psoriasis is a chronic (long-lasting) skin disease of scaling and inflammation.
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.
What are the symptoms of psoriasis?
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.
Who gets psoriasis?
Just over 2 percent of the U.S. population is affected by psoriasis. Although the disease occurs in all age groups, it primarily affects adults. It appears about equally in males and females.
What causes psoriasis?
Psoriasis is a skin disorder driven by the immune system's T cells. Normally, T cells help protect the body against infection and disease. In the case of psoriasis, T cells are put into action by mistake and become so active that they trigger other immune responses, which lead to inflammation and to rapid turnover of skin cells.
In about one-third of the cases, there is a family history of psoriasis.
How is psoriasis treated?
Doctors generally treat psoriasis in steps based on the severity of the disease.
In step 1, medicines are applied to the skin (topical treatment). These can include ointment or cream forms of corticosteroids, vitamin D3, retinoids, coal tar, or anthralin.
Step 2 uses light treatments (phototherapy).
Step 3 involves taking medicines by mouth or injection that treat the whole immune system (called systemic therapy). Recently, attention has been given to a group of drugs called biologics (for example, alefacept and etanercept), which are made from proteins produced by living cells instead of chemicals.