Psoriasis causes and treatments
Your skin and psoriasis
Psoriasis is a common and chronic condition that usually causes patches of itchy, scaly, and sometimes inflamed skin.
Although they can appear anywhere, these patches, called plaques, are most likely to crop up on your knees, elbows, hands, feet, scalp, or back. The fingernails and toenails are also affected in about 50% of active psoriasis cases.
The symptoms of psoriasis can vary a great deal depending on their severity, ranging from mildly annoying to truly debilitating.
While the itchiness can be unpleasant, some of the worst effects of psoriasis can be emotional. People with severe psoriasis are sometimes so overwhelmed by their condition and self-conscious about their appearance that they feel isolated and depressed.
According to the Psoriasis Association, between 2% and 3% of people in the UK have psoriasis. Unfortunately, there isn't a cure. But there are many effective treatments that can help keep it under control.
What causes psoriasis?
Normally, skin cells are constantly being formed deep beneath the surface of your skin. Over about a month, these cells are pushed up to the surface. This is called cell turnover. The cells eventually die and flake off, revealing new skin cells.
In people with psoriasis, the skin cells grow too quickly. The exact cause of psoriasis is not completely understood, but genetic and immune system abnormalities are believed to play key roles in the condition. In psoriasis, cell turnover can happen in a matter of days. A faulty immune system signals an increased growth cycle of skin cells. Layers of skin build up, forming a whitish, flaky crust. Blood vessels increase their flow to the skin in an attempt to nourish this skin, which leads to redness and swelling. The classic symptoms of psoriasis are reddened, inflamed patches of skin with a silvery, flaky layer of dead cells on top. These patches are called psoriatic plaques.
Although psoriasis usually appears as a skin condition, recent discoveries show that its real cause is a problem with the immune system.
Your body naturally fights infections and heals injuries with special cells - called white blood cells - that battle viruses or bacteria. Normally, these cells go to the site of infection or injury to help repair wounds and prevent infection. One by-product of this normal process is inflammation (redness and swelling).
For reasons that doctors don't yet understand, the immune systems of people with psoriasis malfunction. One type of white blood cell, the B-cell, begins creating antibodies that destroy normal skin cells. Another type of white blood cell, the T-cell, begins overproducing a type of protein called a cytokine. This overproduction appears to turn off a signal that controls the growth of skin cells.
So this is why psoriasis is considered an autoimmune disease - your own immune system malfunctions and attacks normal body tissues. Other autoimmune diseases include systemic lupus erythematosus and rheumatoid arthritis.
Psoriasis of the skin or nails may look like a rash or fungus, but you can't catch psoriasis from another person. You also can't give it to anyone else or spread it from one part of your body to another by touch.
Experts now know that there is a genetic component to psoriasis, so if it runs in your family, your chances of developing it are higher. Some people carry genes that make them more likely to develop psoriasis. When both parents have psoriasis, the child may have a 50% chance of developing the condition. About one third of those with psoriasis have at least one family member with the disease.