Psoriasis

Psoriasis is a chronic skin disorder. It’s considered an autoimmune disease. This means your immune system harms your body instead of protecting it. More than 7.5 million people in the United States have this condition.
Psoriasis causes your skin to develop scaly patches that are sometimes silvery or red and can be itchy and painful. The patches can come and go over the course of a few days to over a month.
There are different types of psoriasis, and it’s possible to have more than one type. Read on to learn more about these different types and how they are treated.

There are five official types of psoriasis:
• plaque
• guttate
• inverse
• pustular
• erythrodermic
• psoriatic arthritis

Symptoms

Psoriasis signs and symptoms are different for everyone. Common signs and symptoms include:

• Red patches of skin covered with thick, silvery scales

• Small scaling spots (commonly seen in children)

• Dry, cracked skin that may bleed

• Itching, burning or soreness

• Thickened, pitted or ridged nails

• Swollen and stiff joints

Causes

The cause of psoriasis isn't fully understood, but it's thought to be related to an immune system problem with T cells and other white blood cells, called neutrophils, in your body.

T cells normally travel through the body to defend against foreign substances, such as viruses or bacteria.

But if you have psoriasis, the T cells attack healthy skin cells by mistake, as if to heal a wound or to fight an infection.

Overactive T cells also trigger increased production of healthy skin cells, more T cells and other white blood cells, especially neutrophils. These travel into the skin causing redness and sometimes pus in pustular lesions. Dilated blood vessels in psoriasis-affected areas create warmth and redness in the skin lesions.

The process becomes an ongoing cycle in which new skin cells move to the outermost layer of skin too quickly — in days rather than weeks. Skin cells build up in thick, scaly patches on the skin's surface, continuing until treatment stops the cycle.

Just what causes T cells to malfunction in people with psoriasis isn't entirely clear. Researchers believe both genetics and environmental factors play a role.

FAQ

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