They suffer from a rare genetically inherited condition called Methemoglobinemia characterized by a higher percentage of methemoglobin in the blood - an oxidised form of hemoglobin - causing tissue hypoxia. Basically, less oxygen gets to the tissues so they turn blue, just as you would if you were suffocating. Certain drugs can also cause 'acquired methemoglobinemia', and the classic 'blue-baby' syndrome is caused by nitrates ingested in tap water.
|Argyria sufferers - taken from Wikipedia|
But blue skin isn't the only odd colour change for humans. Carotenosis is a more common one - or one perhaps more well-known - where the excessive intake of carrots (or other vegetables containing the pigment carotene) turns the skin orange. It occurs most often in vegetarians and younger children, and is more noticeable in those with fair skin. It's a benign condition but one likely to draw attention!
|Carotenoderma of the nose - taken from Wikipedia|
Of course, you can brown your skin by tanning in the sun, or by using spray tans. Unless, like me, you're white-skinned and redhaired, burning at the mere touch of a summer sunbeam. But scientists are now looking at the possibility of taking a pill or smearing on a cream to naturally turn your skin darker, or even lighter if you wish it. Skin, hair and eye colour are mostly determined by the pigment melanin. Scientists have been working on a way to chemically stimulate melanin production in the skin of mice to give them natural protection from the sun. The same technique could also be used to lighten skin, and potentially hair and eye colour. All with far less mess than using dyes. Perhaps in the future we might even see a pill that could turn your brown eyes blue. :-P
Or maybe we'll find a way to transplant the chromatophores that allow chameleons to change their colour into our own skins, changing it at will or to match our mood. Would you like the ability to change your appearance with a thought? Or might it lead to public embarrassment if the colour change revealed your secret feelings for someone in public? No more guessing if that man across the room is giving you the eye or has noticed that your skirt is tucked in your knickers. Passion and hate shown by a single, simple colour change.
And if we could change the colour of our skin to show our true feelings, would we give up wearing clothing? Who needs that little black dress when we can change our skin to every colour of the rainbow. How might our language change? Would we give up speech and communicate in colour?
So what colour would you like to be today?