A dark skin spot is an irregular accumulation of melanin caused mainly by exposure to the sun. However, some inflammatory processes can also cause dark spots.

The different types of dark spots include: melasma, i.e., light brown spots on the cheeks, forehead or chin that present during pregnancy or due to hormone-based contraceptive use; freckles; vitiligo, characterised by areas with no pigmentation; moles; liver or sun spots, and couperosis, spots caused by the dilation of small veins on the face.

Melanin in humans is found in the skin, hair and retina. It acts as a chemical filter (protecting the DNA), absorbs radiation (and disperses it in the form of heat) and has antioxidant properties.