Etiopathogenesis of Melasma

Abstract

Known since ancient times, melasma is notoriously a frequent dyspigmentation disorder characterized by localized, chronic acquired cutaneous hypermelanosis. Despite high frequency, significant negative effects on quality of life and often unsatisfactory results of available treatment, not much research has been performed on the etiopathogenesis of this disease, which still remains largely obscure. An extensive review of the literature on etiology and pathogenesis of melasma is presented here, in which known causal/exacerbating factors (sun exposure, alterations of hormonal balance, use of cosmetics and photosensitizing drugs, procedures and inflammatory processes of the skin, stressful events) are linked with their effects on multiple metabolic pathways of melanocytes and other components of the socalled “melanin unit”. Available data outline an incompletely defined, but certainly complex and somehow fascinating network of interactions of structural and functional alterations, which deserves further investigation, not only to obtain new and better treatments for melasma, but also –and probably more important in view of a more detailed understanding of the entire physiology and pathophysiology of melanogenesis, with many possible applications in the vast field of dyspigmentation disorders