New data on hyperpigmentation disorders.

Recently visible light (VL) and vascularization triggered by infrared light (IR) play a role in hyperpigmentation disorders of the skin. The aim of this article is to provide an update on the aetiology of hyperpigmentation disorders and means of prevention against UV, visible (VL) and infrared light (IR). The author conducted a literature review of the most recent data about hyperpigmentation disorders and means of prevention and protection. VL impacts on pigmentation, especially in individuals with phototype III, IV or V and also causes the production of Reactive Oxygen Species (ROS), erythema and DNA damage through ROS production as well as photodermatoses. IR is supposed to be involved in melanogenesis throughout the activation of the endothelin receptor B and the mitogen-activated protein kinase, extracellular signal-regulated kinase (ERK)1/2, and protein (p)38. To protect from hyperpigmentation caused by VL, sunscreens containing iron oxides are efficient. The development of systemic antioxidants and new UV-VL sunscreens which allow absorption of the energy in the VL spectrum without reflection may provide further protection. With no existing organic or non-organic filters able to absorb or reflect IR, topical antioxidants may be able to provide some protection against damage caused by IR. However, their clinical efficacy still needs to be confirmed. In conclusion, UV, VL and IR light induce pigmentation. To prevent hyperpigmentation, protection using adequate sunscreens on exposed areas is needed. To date, no efficient protection from IR light exists, but topical antioxidants may be able to provide some protection.