It must be remembered that psoriasis is a chronic health condition that is not curable in the usual sense. The disease is characterized by exacerbations and remissions that often seem to occur spontaneously. Patients often relate some incidental environmental event or psychological stress to changes in their disease's activity. This can complicate treatment.Since psoriasis is incurable, doctors treat the condition to enhance the patient's sense of well-being and independence. Treatment options are chosen that are appropriate to the severity of the condition. Mild, localized psoriasis is treated with topical therapy while more extensive, severe disease will require systemic, expensive, and potentially hazardous treatment.