There have always been tales of blue people in mythology, popular fiction, and in the news. Yes, blue people exist here and there in the real world.
Two conditions cause people to live and be (literally) blue. Methemoglobinemia is a condition in which the blood carries less-than-normal amounts of oxygen, making the blood appear blue. Argyria is caused by the ingestion of silver, usually for medicinal purposes. The effects of silver ingestion are permanent, and if the consumption of silver continues long enough, can be fatal.
Methemoglobinemia can be acquired through use of certain drugs, or can be inherited through the presence of recessive genes. There have been reports of blue families or tribes through history that could be explained by inherited Methemoglobinemia. The best-documented of these is the Blue Fugates of Kentucky.
Martin Fugate emigrated from France in 1820 and married Elizabeth Smith, a Kentucky native. Apparently, both had the very rare recessive gene for Methemoglobinemia. Four of their seven children were blue! They lived in an isolated area of eastern Kentucky and their children grew up and married those who lived close to them, meaning a very few families in the area, or even their own cousins. One Fugate son married his mother's younger sister. Over several generations of intermarriage within these same few clans, the recessive genes were preserved and the Fugates came to be known as the Blue Fugates. The exact reason for their color wasn't known until medical tests were conducted in the 1960s. In the early 80s, only three blue members of the Fugate family were reported surviving.
Before the advent of antibiotics, silver nitrate and colloidal silver were used as antiseptics. Captain Fred Walters was prescribed silver as a remedy for locomotor ataxia, a degenerative neural disease. ItÂ turned his skin so blue that by 1891, he was exhibiting himself at side shows for profit. At the time, the poisonous effects of silver were unknown. Walters continued to take silver to maintain his profitable blue coloring until his heart gave out in 1923. He had essentially died of silver poisoning.
Because of "products containing silver, which have flooded the market in past years", the state of Florida posted a warning that silver is unsafe to consume. Accompanying the warning are these photos of a victim of argyria, shown beside a healthy man to highlight the difference in color. Online information on the safety and efficacy of colloidal silver supplements varies from "no side effects at all" to "unsafe and ineffective", depending on where the funding comes from. The FDA says such products are not judged to be safe.
Rosemary Jacobs began using nose drops containing colloidal silver when she was 11 years old. Within a few years, her skin had turned blue. Despite discontinuing the use of colloidal silver, Jacobs face remained blue for decades, as particles of silver were embedded in her skin and organs. In the 70s (after this picture was taken), Jacobs underwent dermabrasion treatments, which removed the top layers of her skin. She now has blotchy pink skin. Jacobs is campaigning against colloidal silver dietary supplements because of what happened to her.
Paul Karason began using colloidal silver 15 years ago. He believes his blue skin was caused by rubbing the concoction on his skin to treat dermatitis, and not by drinking it. Karason, who is sometimes referred to as "Papa Smurf" continues to drink colloidal silver as a cure-all. See a video report here.
Montana Libertarian Stan Jones was an unsuccessful candidate for the US Senate in 2002 and in 2006. He is also a victim of argyria. Jones began using colloidal silver he made himself in anticipation of antibiotic shortages predicted from the Y2K scare. He continues to take colloidal silver and believes in its health benefits.
There are other conditions that can cause the skin to turn blue, usually due to lack of oxygen, but serious cyanosis must be treated immediately and is not a condition people can just "live with". And then there are people who go the extra mile to appear blue.