What You Should Know About Psoriasis

Take charge by learning as much as you can about psoriasis. The more you understand your condition, the easier it will be to manage.

What Causes Psoriasis?

Psoriasis seems to run in families. It’s a problem with the immune system.

When it works right, your immune system fights infections and heals injuries with white blood cells. If you have psoriasis, though, one type of white blood cell, the B-cell, creates antibodies that destroy normal skin cells.

Meanwhile, another type of white blood cell, the T-cell, starts to make too much of a protein called a cytokine. This seems to turn off a signal that controls the growth of skin cells.

Normally, skin cells last for about a month. Then they die, flake off, and are replaced by new ones.

If you have psoriasis, your immune system causes this cell turnover to happen in days instead of weeks. Layers of skin build up. Blood flow increases to try to nourish this skin, which leads to redness and swelling. You get reddened, inflamed skin with a whitish, flaky crust of dead cells on top.

How It Affects You

You may get patches of itchy, scaly, or inflamed skin called plaques. Though they can appear anywhere, you're most likely to get them on your knees, elbows, hands, feet, scalp, back, or belly button.

You may also get pits in your fingernails and toenails. About half of people with active psoriasis do. Up to 30% also get psoriatic arthritis, which causes pain, swelling, and stiffness in and around your joints.

Everyone is different. Your symptoms may be milder or more severe than someone else’s.

Try not to let psoriasis affect your social life or confidence. You can do all the things that anyone else does. If you feel like you're getting depressed, talk to your doctor or a counselor.

Different Kinds Have Different Symptoms

Plaque psoriasis. About 80% of people with psoriasis have this. It causes the raised red patches with white scales.

Guttate psoriasis. Children, teenagers, and young adults are most likely to get this. It often appears after an infection, such as strep throat. It causes red, scaly, raindrop-shaped spots, usually on the belly, arms, legs, and scalp. It often clears up on its own without treatment.


Pustular psoriasis . Pus-filled blisters on hands and feet are the hallmarks of this type of psoriasis. The blisters usually dry up, turn brown, become scaly, and peel off.

Erythrodermic psoriasis. This causes fierce red and scaly skin over large areas of your body. It can develop from other forms of psoriasis. Psoriasis treatments or withdrawal from certain drugs, like corticosteroids, can trigger it.

Inverse psoriasis. You get scaly and bright red patches in the folds of your skin -- for instance, under your breasts, in your armpits, or on your genitals. Obesity can make it worse.

It Comes and Goes

Psoriasis symptoms will change over time. You may only have minor symptoms once in a while. Or you may have severe symptoms most of the time. Certain things, like dry weather or stress, can cause them to flare up.

Though it's rare, very severe psoriasis can be dangerous. You need to see your doctor right away if your psoriasis spreads to cover large parts of your body or if you show signs of infection, such as fever.

To manage your psoriasis, work closely with your doctor and get support from your family and friends.

WebMD Medical Reference Reviewed by Debra Jaliman, MD on November 02, 2015



Bruce E. Strober, MD, PhD, associate director of dermatopharmacology, department of dermatology, New York University School of Medicine; co-director, Psoriasis and Psoriatic Arthritis Center.

Jeffrey M. Weinberg, MD, director, clinical research center, St. Luke's-Roosevelt Hospital Center, New York City; assistant clinical professor of dermatology, Columbia University College of Physicians and Surgeons.

National Institute of Arthritis and Musculoskeletal and Skin Diseases.

American Academy of Dermatology.

National Psoriasis Foundation.

Abel, E. ACP Medicine, April 2005. 


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