Psoriasis is an autoimmune and inflammatory disease with genetic predispositions that generally occurs before age 35. The development of the disease is driven by multiple pathways of immune mediators, including tumor necrosis factor-α (TNF-α), interleukin (IL)-23 and IL-17 cytokines. Psoriasis affects about 3% of the population and is associated with systemic diseases including inflammatory bowel disease, metabolic syndrome, and cardiovascular disease. Plaque psoriasis is the most common form of the disease, accounting for about 70% to 90% of all patients with psoriasis.