POMC and psoriasis: Although the pathomechanisms by which psychological stress is involved in the pathogenesis of psoriasis are not clear, evidence suggests a regulatory role of psychologic stress in immune functions, including increasing expression levels of proinflammatory cytokines and intracellular adhesion molecule-1 (ICAM-1), and decreasing anti-inflammatory cytokines and the function of glucocorticoid receptors, possibly in part via activation of corticotropin-releasing hormone (CRH)-proopiomelanocortin (POMC)-adrenocorticotropic hormone (ACTH)-corticosteroids axis.