Family history has been found to play a role in around one third of cases. The genes that predispose some people to psoriasis are involved in the immune response and the hyperreactivity of the skin, which cause its quicker renewal and over-reaction.
FACTORS THAT AGGRAVATE BUT ARE NOT RESPONSIBLE FOR PSORIASIS
Environmental factors can trigger the aggravation of the condition, but are not responsible for the psoriasis itself. Psoriasis is not a psychosomatic illness. Stress and anxiety are not causes of the condition. That said, a person who is predisposed to this illness may experience a flare-up during an emotional event. Other contributing factors can have various origins. Alcohol abuse and obesity make psoriasis worse. A small number of medications are also known to aggravate this dermatological condition. Any skin irritation due to trauma such as rubbing, a scrape, a scar or a burn may encourage psoriasis to develop, often in a very localised form at the site of the wound. Scratching a psoriatic plaque prevents it from healing.