"We are like chameleons, we take our hue and the color of our moral character, from those who are around us."

These are powerful words from 17th century philospher John Locke, but ultimately — at least scientifically — he's wrong. Human skin color is governed by biology, sometimes by genes, other times by design (see below). A report in the New England Journal of Medicine highlights an uncommon skin condition that made a baby turn half-red. How did this happen and what other conditions can impact skin color?

Normal Skin Color

Typically the color of our skin, eyes, and hair is controlled by special cells called melanocytes, which produce two types of a natural pigment called - melanins.

Typical hues of skin are due to "eumelanin" — conveniently pronounced "you" + "melanin" — which is black-brown. Higher levels of eumelanin equal darker skin tones. Pheomelanin is a reddish-pink pigment that is most commonly found in red hair, but also in the lips, nipples, penis, and vagina.

A Half-Red Baby

In India, a four-day-old baby's body recently turned half-red, due to a rare condition called harlequin color change. Affecting about 10 percent of healthy newborns, the condition comes and goes, usually after a child was lying on its side, and can persist for up to three weeks. Each episode lasts between 30 seconds to 20 minutes and isn't thought to be harmful.

The leading theory is that vasodilation — widening of arteries and veins — allows extra red blood cell to travel into the vessels of the skin, causing discoloration.

A 4-day-old, full-term, healthy female infant underwent a change in skin color from normal to red over one half of her body. The change in color, which persisted for a week, was consistent with harlequin color change — the development of redness on the dependent side of the body, with simultaneous blanching of the contralateral side. (Credit: The New England Journal of Medicine ©2013.)

The Real "Blue Man" Group

Consuming chemical compounds with silver can turn a person blue, which is known as argyria, The most famous case of argyria arguably belongs to Paul Karason, who believed that drinking silver in his water on a daily basis could cure his skin dermatitis, even though FDA says otherwise.

Blue skin can also be caused by genetic blood disorder called methemoglobinemia. People with the disease produce large amounts of methemoglobin, a type of hemoglobin, which is the protein that blood cells use to carry oxygen. Methemoglobin struggles to release the oxygen, leading to the change to smurf-dom.

Going Green

Another illness involving hemoglobin is hypochromic anemia, which makes skin look green. In this case, hemoglobin levels are too low, which can lead to under-sized red blood cells. Common causes: iron deficiency and thalassemia.

A hand demonstrating extra pallor. (wikimedia)

Orange

That old joke about how eating too many carrots will turn your skin orange is actually steeped in science and explains why certain tanning products yield the same effect.

Carrots packed with a compound called carotene, which belongs to family of orange pigments called carotenoids. Our cells need carotene to make vitamin A, which is important for eye and skin health. Regular levels of carotene are easily excreted by the body by sweating or urinating, but too much consumption can lead to 'carotenaemia' — orange skin — as the compound accumulates. The condition is typically harmless and dissipates after a few months.

Tanning pills, which the Mayo Clinic and FDA deem as unsafe, contain canthaxanthin, which is a carotenoid that sometimes turns skin orange. Most spray tans don't use carotenoids, but instead contain dihydroxyacetone (DHA). This compound reacts with amino acids in the upper layers of the skin, yielding fake tans

Carotenemia: Before & After
24 year old female with Carotenemia on palms: before and after the usage of high doses of carotene was discontinued; discoloration due to excessive consumption of V8 Splash

Source: Adhisivam B, Chandrasekaran V. A Half-Red Baby. NEJM. 2013.