Skin Colour

Skin gets its colour from melanin - a brown pigment that is made in the melanocytes found in the lower layers of the epidermis; the natural yellow pigment of the skin cells; and from the colour of blood in tiny blood vessels called capillaries, just below the skin's surface.

our skin colour is inherited from our parents and is determined by a set of genes that control the amount of melanin in our skin. Albinism is a genetic disorder in which melanin production is reduced or absent altogether. Since melanin is also found in hair and eyes, albinos often have light or white skin and hair, and pale or pink eyes. It is a rare condition and affects all races but is most common in the Ibo people of Nigeria.

A melalnocyte looks a little like an octopus, with its head in the basal cell layer and its tentacles reaching up into the epidermis. Under the influence of a hormone called melanocyte-stimulating hormone (MSH), the melanocytes produce melanin. The tentacles distribute the grains, called melanosomes containing the melanin, into the higher layers of the epidermis.

Inside the melanocytes, melanin is formed when an amino acid called tyrosine, is oxidized. This oxidation is often caused by ultraviolet light or by an enzyme called tyrosinase. The main function of the melanin is to absorb harmful ultraviolet rays before they reach the deeper layers of living skin cells.

IT'S FACT
Hydroquinone lightens the colour of the skin by reducing melanin production by inhibiting tyrosianse. Some dark-skinned people use it to bleach their skin in order to disguise their racial origins. This practice is not recommended . hydroquinone is now banned from skin-lightening products sold in the EU.

Both dark and light-skinned races seem to contain the same number of melanocytes in their basal layer of skin cells but light-skinned people have an enzyme that breaks down the melanin shorty after it is produced., and so very little melanin reaches the outer layer of skin. Ultraviolet rays stimulate the melanocytes to produce extra melanin, resulting in a suntan.

if you are one of those people who finds it hard to get a tan, you have an efficient enzyme system that breaks down the melanin as rapidly as it is formed.

Melancoyte-stimulating hormone is produced in the pituitary gland. Changes in the level of this hormone, possibly as a result of injury, illness, or the use of some drugs, can cause changes in the colour of the skin.

Hence we hear horror stories of the dark-skinned individuals who have become pale, and have little natural protection from the sun, or white people who become dark skinned.

Blood vessels close to the surface of the skin can give it a red or blue tint. if we are hot or flushed, the blood vessels become larger and a greater volume of blood flows to the skin, giving it a pink or red hue. On cold days the blood vessels become narrower, slowing down the blood flow. The blood loses its oxygen and picks up carbon dioxide.

This deoxygenated blood has a blue or purple colour and is not carried away quickly, so our skin may acquire a blue tint. These colour changes are more noticeable in light -skinned people.

A number of harmless skin disorders may cause dark or light patches to form on the skin. These can be disguised with make-up, but if the condition worsens, or you have any other symptoms such as reddening or irritation, you should consult your doctor.

Reference: Cosmetics Unmasked: Dr Stephen & Gina Antczak