Psoriasis

Causes and Risk Factors

Although the cause of psoriasis is not completely understood, scientists believe it is related to a problem with a type of blood cells called T cells. These cells normally travel through the bloodstream to help fight an infection, but in people with psoriasis, they attack the body’s skin cells by mistake.

Genes Play a Role

No one knows what causes T cells to go wrong, but certain genes have been linked to psoriasis. People who have these genes are more likely to develop psoriasis than people without the genes. However, genes alone do not cause psoriasis. Scientists believe psoriasis occurs when something in the environment triggers the disease in someone who has one or more of these genes.

Psoriasis Triggers

These so-called triggers may be different for different people. Different triggers may start the disease or make it worse in different people.

Factors that may trigger psoriasis or make it worse include

• physical and emotional stress
• injury to the skin such as cuts or burns
• infections, particularly strep throat
• cold weather
• smoking or heavy alcohol use
• certain medications such as
• lithium, a psychiatric drug
• antimalarials such as hydroxychloroquine and chloroquine
• inderal, a high blood pressure medicine
• quinidine, a heart medication
• indomethacin, a nonsteroidal anti-inflammatory drug often used to treat arthritis.