Genes control everything about people; they are what make people unique. When genes function correctly, they keep the body in a state of balance or homeostasis; if abnormalities occur, diseases can develop. Ten percent of Americans inherit genes that increase the likelihood of developing psoriasis, yet only two or three percent develop the condition.
Identification of 25 gene variants shows which individuals are at a higher risk of developing psoriasis. One genetic mutation linked to plaque psoriasis is the CARD-14 gene. Another gene, IL36RN is linked to pustular psoriasis. Scientists believe that these variants affect the behavior of immune system cells called lymphocytes, causing them to attack healthy cells instead of viruses and bacteria.
The question remains, why do the two or three percent develop psoriasis? Researchers feel there must be environmental triggers that cause the immune system to go haywire. Possible triggers include trauma, including an injury to the skin, such as a scratch, cut, or burn; stress; smoking; heavy alcohol consumption; a bacterial infection -typically streptococcus (strep throat); and medications, such as lithium, beta-blockers for high blood pressure, certain heart medications, steroids, or antimalarials.
MALFUNCTIONING IMMUNE SYSTEM
If the skin feels that it is under attack, the immune system will go into overdrive. The overactive immune system response caused by psoriasis results in: enlarged blood vessels; accelerated keratinocyte differentiation rapidly producing new cells, reaching the surface in four to five days instead of 28 to 30; an elevated number of T-cells, keratinocytes, and immune system cells; cells that are unable to desquamate normally; development of thick, scaly patches due to the accelerated turnover process; or inflammation and erythema.