Carpal Tunnel Syndrome And Tarsal Tunnel Syndrome Carpal tunnel syndrome is a condition in which irritation of the wrist's median nerve causes tingling and numbness of the thumb,...learn more Â». In This Article.
1 Argyria-characterised by a metallic, slate-grey or blue-grey pigmentation. 2  The hyperpigmentation is most apparent in the UV-exposed areas of skin, especially the forehead, nose, and hands, as well as mucous membranes. 3  Argyria results from prolonged contact with or ingestion of silver salts.
Melanin is the substance that gives skin its color, or pigment. When the skin cells that produce melanin (melanocytes) reduce their production, the resulting condition is known as hypopigmentation (loss of skin color). Hypopigmentation is also known as skin depigmentation. The most common cause of hypopigmentation is damage or trauma to the skin.