Argyria: The rare disease that turns people blue

Disease name: Argyria

Affected populations: Although more common in the 19th century because of heavy exposure to silver among people who worked with the metal and the use of silver to treat diseases, argyria is now a rare condition. Consequently, there are limited statistics on the true incidence of the disease. However, one review of medical literature published up to 2018 identified 16 patients who developed argyria after exposure to a liquid suspension of silver, known as colloidal silver.

Causes: Argyria is caused by the ingestion of — or exposure to — silver or silver-containing compounds. The silver accumulates in the body and thus turns the skin and nails bluish-gray. The human body normally contains tiny amounts of silver from more minor exposures, such as from food and drinking water. But in patients with argyria, these levels have built up in excess over a long period of time, ranging from several months to years.

People who work with silver or use colloidal silver as a dietary supplement are at the greatest risk of developing argyria. This includes people who consume colloidal silver as a form of alternative medicine in an attempt to treat conditions such as high blood pressure and diabetes. U.S. health officials have warned that the compound isn't effective for treating any condition and that it can interfere with certain drugs, such as antibiotics.

Related: Butterfly disease: A disorder that makes skin as delicate as butterfly wings

Symptoms: The main symptoms of argyria are the skin developing a bluish-gray or gray tint, the fingernails growing darker than normal, and darker patches appearing on skin in areas that are exposed to the sun — a condition known as hyperpigmentation. These color changes are typically permanent, and patients with argyria may experience psychological distress because of their appearance.

Symptoms can vary depending on how much silver enters a person's body, how it enters the body, and how long it has accumulated. Symptoms may occur across the entire body (generalized argyria), only select parts of the body (localized argyria) or specifically in the eye (argyrosis).

Argyria can also cause other symptoms — such as abdominal pain, fatigue, headaches and kidney damage — but it is not life-threatening. That said, ingesting large amounts of silver in one go can be fatal.

Treatments: There is currently no cure for argyria. Laser therapy has been tested as a means to improve the appearance of discolored skin in patients with argyria in several studies, without success.