What Is Psoriasis?

Psoriasis is a chronic, or long-term, skin disease. Those who have this disease will usually grow rashes, plaques, and dry, scaly skin, which may appear anywhere on their bodies, but most commonly on the elbows, knees, torso, and scalp. The direct cause of psoriasis is currently unknown, but is thought to be the result of an immune-mediated issue, due to inflammation of the skin. Inflammation is a sign of a functioning immune system; however, psoriasis occurs when infection-fighting cells attack healthy skin cells by mistake.

Normally, skin cells would mature in about a month. With psoriasis, however, skin cells would complete the same amount of growth in about three or four days. Unlike normal skin cells, which sheds after maturation, psoriasis causes the rapidly maturing skin cells to pile up on the surface of the skin, resulting in plaques and scales.

While the causes of psoriasis are unclear, researchers believe that both genetic and environmental factors play a major role in its development. Despite the unknowns, there are some things that we do know about psoriasis. First, we know that psoriasis can develop at any age, but symptoms most commonly appear around ages 15-25. Secondly, we know that it is not contagious. This means that a person will not contract psoriasis from another person, and it must come from a trigger. There are many factors that may trigger the development or induction of psoriasis flares – including bacterial infections like strep throat or skin infections, weather, certain medications (including lithium, high blood pressure drugs, and antimalarial drugs), smoking, or rapid withdrawal of oral or injected corticosteroids. Finally, in many instances, having a family history of psoriasis means a higher risk of having psoriasis themselves. If a person has one parent that has psoriasis, their risk of developing it is increased by 10%. If both parents have it, then their risk increases to 50%.