An overactive immune system that causes skin cells to proliferate too quickly is the cause of psoriasis, a chronic skin disorder. Although the precise cause is unknown, it is associated with heredity and can be brought on or made worse by stress, infections, skin injuries, cold weather, alcohol, smoking, certain medications, or insufficient sleep. It doesn't transfer from person to person and is not infectious. Treatment helps manage flare-ups and lessen symptoms, which typically include red, thick, scaly, itchy areas on the skin.