Skin | Dermatology | Skin Lightening (Symptom)
Each person has a specific colour of the skin, which is due to the kind, amount and distribution of a melanin pigment. Melanin is synthesized by the action of an amino acid called tyrosine. This occurs in cells (melanocytes) present in the epidermis (the outermost layer of skin). It is for this reason that all individuals have a characteristic pigmentation in their skin.
Depigmentation of the skin can be caused by a number of local and systemic conditions. The pigment loss can be partial (and after skin injury) or complete (vitiligo). It may be temporary or permanent (e. g. albinism).
The spots produced by the depigmentation may occur externally or internally. The external are known by the name of melasma, and generally have nothing to do with exposure to the sun. It is linked to hormonal problems or a different pathology. External staining, by contrast, generally takes place because of the incidence of solar radiation directly to the skin. Furthermore, there may be by use of poor quality or cosmetics containing high levels of dyes from mercury, aluminum oxide or iron oxide.