Psoriasis Causes

Conditions & Diseases: Skin Diseases - Psoriasis

Immune Related: The majority of research into the causes of psoriasis place the blame on an immune-mediated disorder. A type of white blood cells called T cells are tasked with protecting the body from infections and diseases by attacking bacteria and viruses. In patients with psoriasis, these T cells receive faulty signals, move to the outer skin layer (dermis) and cause inflammation and the rapid production of skin cells by triggering the release of cytokines (a protein the promotes inflammation) (1,2,3,4). When they grow at a faster rate and are not shed, these skin cells - "...pile up in raised patches on the outer surface of the skin."(5)

The National Institue of Arthritis and Musculoskeletal and Skin Diseases illustrates the process another way:

Psoriasis is an autoimmune disease in which newly forming skin cells rise to the surface of the skin before they have a chance to mature. These cells piling up on the surface of the skin result in patches of thick, inflamed skin often covered with silvery scales. These patches, called plaques, normally itch and feel sore.(2)

Gene: In June of 2006, the American Journal of Human Genetics reported that researchers had identified the gene which causes a susceptibility to psoriasis. The reported stated that the gene, PSORS1, and a specific gene allele, HLA-Cw6, play a role in determining who gets psoriasis.(7) Since these genes determine how a person's immune system reacts, they can cause other immune related disorders. "The risk of developing psoriasis or another immune-mediated condition, especially diabetes or Crohn’s disease, increases when a close blood relative has psoriasis."(3) As stated in the Overview section, 10 to 30 percent of patients with psoriasis develop psoriatric arthritis, a condition which causes inflammation, swelling and pain in the joints.

Heriditary: About one-third of those with psoriasis have a family member with the disease. When both parents have psoriasis, there is a 50-percent chance their child will have psoriasis.