Argyria

Argyria or argyrosis is a condition caused by excessive exposure to chemical compounds of the element silver, or to silver dust. The most dramatic symptom of argyria is that the skin turns purple or purple-grey. It may take the form of generalized argyria or local argyria. Generalized argyria affects large areas over much of the visible surface of the body. Local argyria shows in limited regions of the body, such as patches of skin, parts of the mucous membrane or the conjunctiva. Argyria or argyrosis is a condition caused by excessive exposure to chemical compounds of the element silver, or to silver dust. The most dramatic symptom of argyria is that the skin turns purple or purple-grey. It may take the form of generalized argyria or local argyria. Generalized argyria affects large areas over much of the visible surface of the body. Local argyria shows in limited regions of the body, such as patches of skin, parts of the mucous membrane or the conjunctiva. The terms argyria and argyrosis have long been used interchangeably, with argyria being used more frequently. Argyrosis has been used particularly in referring to argyria of the conjunctiva, but the usage has never been consistent and cannot be relied on except where it has been explicitly specified. The term is from Ancient Greek: ἄργυρος argyros silver. In humans and other animals chronic intake of silver products commonly leads to gradual accumulation of silver compounds in various parts of the body. As in photography (where silver is useful because of its sensitivity to light), exposure of pale or colourless silver compounds to sunlight decomposes them to silver metal or silver sulfides. 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 eyes. In the conjunctiva this is not generally harmful, but it also may affect the lens, leading to serious effects. Localised argyria often results from topical use of substances containing silver, such as some kinds of eye drops. 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. While silver is potentially toxic to humans at high doses, the risk of serious harm from low doses, given over a short term, is slight. 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. 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 µg/(kg·d).