Nail Pigmentation

Nail pigmentation is most commonly due to exogenous staining of the nail plate. In this case the proximal margin of the pigmentation follows the shape of the proximal nail fold. Exogenous nail pigmentation is most commonly due to occupational exposures or nail cosmetics. Nail pigmentation due to endogenous causes is rare. The proximal margin of the pigmentation follows the shape of the lunula . Possible causes include drugs, argyria, hemochromatosis, alkaptonuria, and Wilson disease