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.
The relative proportions of these pigments give us the variations we see in skin colour: more melanin will give darker brown to black skin tones, more carotene is responsible for the yellow to reddish tones and the hemoglobin gives red to pinkish tones.