This happens because “Each of us produces a different quantity and quality of melanin. Melanin is a pigment produced by our cells found in the basal layer of the skin,” explains Dr Puig.
If the skin has been inflamed or is severely dry, the melanocytes (cells that give the skin its color) in that area do not react to UV light the same as they do in non-affected or dry skin areas.
Hair and Skin Color: If you have lighter hair or skin on your legs, they may not tan as easily compared to darker areas of skin. Positioning: How you sit or lie in the sun can also affect exposure. If your legs are often in the shade or not facing the sun directly, they may not tan as much.
One of the more common causes of an uneven skin tone is hyperpigmentation, where the skin overproduces a pigment called melanin. This condition has various causes, such as injury to the skin, medications, genetics, and underlying medical conditions.
Hypopigmentation is a condition in which patches of skin appear lighter than others. It occurs when the body doesn't produce as much melanin as it should. Hypopigmentation often shows up as lighter patches or as white-looking areas on your skin.
The activation and production of melanin is responsible for skin pigmentation and the dark colour on your skin. Compared to the rest of the body, skin on the legs does not produce the same amount of melanin, which results in legs getting less tan.
Uneven pigmentation
That extra melanin is what creates a suntan. But sometimes skin doesn't make melanin evenly. As a result, the skin's coloring, called pigmentation, looks patchy. The sun also can cause small blood vessels to stretch, giving skin a blotchy look.
Look into a mirror in natural light. Artificial lighting can alter the appearance of your natural skin colour. Notice the colour of the skin along your jawline or behind your ear. These areas typically tend to show your skin tone in its purest form, without any redness or discolouration that could get in the way.
Previous research by Rees has confirmed what sun worshippers already knew: that the upper back is much more likely to tan than the legs, and that the outsides of the arms go brown far quicker than the insides.
The natural oils on your skin, which help absorb UV light, are typically lower on the legs, making it harder for them to tan.
For example you may find that your stomach will tan a lot darker than the insides of your arms and legs. This is because your stomach contains far more pigment forming cells (cells that are able to produce melanin when exposed to UV light).
Sometimes the white spots are merely scars that have become more visible after tanning. These areas of the skin have lost their pigmentation due to damage to the tissue.
Vitiligo can start at any age, but usually appears before age 30. Depending on the type of vitiligo you have, it may affect: Nearly all skin surfaces.
According to a study called “Shades of beauty,” light brown skin tones are often the most physically attractive skin color (Frisby et al., 2006). They used four models for that study. They did not change the skin tone, but they imaged each model to three different skin tones: light, medium, and dark.
People with a rare condition called methemoglobinemia have actual blue skin. The Blue Fugates of Kentucky are the only known family carrying this trait.
While relatively small quantities of water appear to be colorless, pure water has a slight blue color that becomes deeper as the thickness of the observed sample increases. The hue of water is an intrinsic property and is caused by selective absorption and scattering of blue light.
"White spots on the skin are related to a lack of melanin, a pigment that the skin produces in response to sun exposure to defend itself, which can depend on a variety of factors, from hereditary to the presence of a fungus.
Some people naturally have uneven skin pigmentation, meaning they have more melanin in certain areas of their faces. This can cause those areas to tan faster and more deeply, resulting in a patchy appearance. Uneven skin pigmentation can also be caused by factors such as hormonal imbalances, age, and genetics.
Sun spots are caused by exposure to ultraviolet (UV) light. Specifically, UV light speeds up how much melanin (the skin's natural pigment) the body produces. Melanin can build up on areas of the skin that have received repeated and intense sun exposure, resulting in darker-looking spots on the skin.
The primary stimulus for melanogenesis and subsequent melanosome production is UV radiation, which upregulates melanocyte production of pro-opiomelanocortin (POMC) and its downstream products, alpha-melanocyte-stimulating hormone (alpha-MSH) and adrenocorticotropic hormone (ACTH).