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.
Eumelanin is a dark pigment that gives hair a brown or black color. Pheomelanin is a lighter pigment that gives hair a red, orange or yellow-ish color. Both of these are present in varying degrees â a person might have a little of each, or a lot of one and almost none of the other.