Editing Argyria (section)

==Pathophysiology==

In humans and other animals, chronic intake of silver products commonly leads to the gradual accumulation of silver compounds in various parts of the body.<ref name="FungBowen1996">{{cite journal |vauthors=Fung MC, Bowen DL |title=Silver products for medical indications: risk-benefit assessment |journal=Journal of Toxicology. Clinical Toxicology |volume=34 |issue=1 |pages=119–26 |year=1996 |pmid=8632503 |doi=10.3109/15563659609020246}}</ref>  As in [[analog photography]] (where silver is used for its sensitivity to light), exposure of pale or colorless silver compounds to sunlight decomposes them to silver metal or [[silver sulfide]]s. Commonly these products deposit as microscopic particles in the skin, in effect a dark pigment. This condition is known as argyria or argyrosis.

Chronic intake also may lead to silver pigments depositing in other organs exposed to light, particularly the [[human eye|eyes]].<ref name="Lansdown2006">{{cite book |author=Lansdown AB |title=Biofunctional Textiles and the Skin |chapter=Silver in health care: antimicrobial effects and safety in use |volume=33 |pages=17–34 |year=2006 |pmid=16766878 |doi=10.1159/000093928 |series=Current Problems in Dermatology |isbn=3-8055-8121-1}}</ref> In the conjunctiva this is not generally harmful, but it also may affect the lens, leading to serious effects.

Localized argyria often results from [[Topical medication|topical]] use of substances containing silver, such as some kinds of [[eye drop]]s. Generalized argyria results from chronically swallowing or inhaling silver compounds, either for home medicinal purposes or as a result of working with silver or silver compounds.<ref name="pmid-16021155">{{cite journal |vauthors=Brandt D, Park B, Hoang M, Jacobe HT |title=Argyria secondary to ingestion of homemade silver solution |journal=Journal of the American Academy of Dermatology |volume=53 |issue=2 Suppl 1 |pages=S105–7 |date=August 2005 |pmid=16021155 |doi=10.1016/j.jaad.2004.09.026}}</ref>

While silver is potentially toxic to humans at high doses, the risk of serious harm from low doses, given over a short term, is small. Silver is used in some medical appliances because of its anti-microbial nature, which stems from the [[oligodynamic effect]]. Chronic ingestion or inhalation of silver preparations (especially [[colloidal silver]]) can lead to argyria in the skin and other organs. This is not life-threatening but is considered by most to be cosmetically undesirable.<ref name="FungBowen1996"/><ref name="Lansdown2006"/><ref>{{cite web | url=https://www.atsdr.cdc.gov/toxfaqs/tfacts146.pdf | title=ToxFAQsTM for Silver | date=July 1999 }}</ref><ref>{{cite web | url=https://www.atsdr.cdc.gov/toxprofiles/tp146-c1.pdf | title=Public Health Statement: Silver | publisher=ATSDR}}</ref>

The [[reference dose]], published by the [[United States Environmental Protection Agency]] in 1991, which represents the estimated daily exposure that is unlikely to incur an appreciable risk of deleterious effects during a lifetime, is 5&nbsp;μg/(kg·d).<ref name="FungBowen1996"/>

Argyria worsens and builds up as exposure to silver continues, and does not resolve once exposure stops because the silver atoms cannot be removed from the skin and other tissues.