Focus on vitiligo: a generalized skin disorder

Vitiligo is an acquired pigmentation disorder due to a disappearance of functioning melanocytes from the epidermis and clinically characterized by achromic patches, often spreading over time. It is still not fully understood how melanocytes disappear in vivo, inducing these peculiar lesions. There are three major hypotheses for pigmentation for the pathogenesis of the disease: the autoimmune hypothesis considers that the disappearance of melanocytes is due to an autoimmune effector mechanism, the neural hypothesis suggests that an accumulation of neurochemical substances is able to damage epidermal melanocytes, and the metabolic hypothesis indicates that an increased sensitivity of melanocytes to oxidative stress is crucial factor of the disease. Besides these well accepted hypotheses there are also some new interpretations based on a defective adhesion of melanocytic cells, an imbalance in the epidermal production of cytokines and an alterated expression of melanocyte receptors.