• melanin
  • There are 4 possible mechanisms to how this change may occur: Accumulation of melanin, the skin pigment Accumulation of drug or one of its products under any layer of the skin (usually the dermis or epidermis) Accumulation of iron throughout the dermis from drug-induced post-inflammatory changes The synthesis of special pigments, under direct influence of the drug Skin lesion Dereure, O. (2001). (wikipedia.org)
  • This single change in SLC24A5 explains between 25 and 38% of the difference in skin melanin index between peoples of sub-Saharan African and European ancestry. (wikipedia.org)
  • Skin has mesodermal cells, pigmentation, such as melanin provided by melanocytes, which absorb some of the potentially dangerous ultraviolet radiation (UV) in sunlight. (wikipedia.org)
  • varies
  • Drug-induced pigmentation of the skin may occur as a consequence of drug administration, and the mechanism may be postinflammatory hyperpigmentation in some cases, but frequently is related to actual deposition of the offending drug in the skin.The incidence of this change varies and depends on the type of medication involved. (wikipedia.org)
  • The thickness of the skin varies considerably over all parts of the body, and between men and women and the young and the old. (wikipedia.org)
  • lighter skin
  • It is theorised that selection for the derived allele is based on the need for sunlight to produce the essential nutrient vitamin D. In northerly latitudes, where there is less sun, greater requirement for body coverage due to colder climate, and frequently, diets poor in vitamin D, making lighter skin more suitable for survival. (wikipedia.org)
  • This may be due to aesthetic or social standing reasons, in areas where a lighter skin tone is considered to be a sign of wealth or beauty. (wikipedia.org)
  • The later additions to the European gene pool, the Early Neolithic farmers from Anatolia and the Yamnaya Copper Age/Bronze Age pastoralists (possibly the Proto-Indo-European population) from the area north of the Black Sea appear to have had much higher incidences of dark eye color alleles, and alleles giving rise to lighter skin, than the original European population. (wikipedia.org)
  • average
  • The SLC24A5 gene's derived threonine or Ala111Thr allele (rs1426654) has been shown to be a major factor in the light skin tone of Europeans compared to Africans, and is believed to represent as much as 25-40% of the average skin tone difference between Europeans and West Africans. (wikipedia.org)
  • For the average adult human, the skin has a surface area of between 1.5-2.0 square meters (16.1-21.5 sq ft. (wikipedia.org)
  • An example is the skin on the forearm which is on average 1.3 mm in the male and 1.26 mm in the female. (wikipedia.org)
  • The average square inch (6.5 cm²) of skin holds 650 sweat glands, 20 blood vessels, 60,000 melanocytes, and more than 1,000 nerve endings. (wikipedia.org)
  • better source needed] The average human skin cell is about 30 micrometers in diameter, but there are variants. (wikipedia.org)
  • high
  • Dark-skinned people who live in high latitudes with mild sunlight are at an increased risk - especially in the winter - of vitamin D deficiency. (wikipedia.org)
  • It also contains DNA repair enzymes that help reverse UV damage, such that people lacking the genes for these enzymes suffer high rates of skin cancer. (wikipedia.org)
  • natural
  • Due to natural selection, people who lived in areas of intense sunlight developed dark skin colouration to protect against ultraviolet (UV) light and to protect their body mainly from folate depletion. (wikipedia.org)
  • million
  • As hominids gradually lost their fur between 4.5 and 2 million years ago, to allow for better cooling through sweating, their naked and lightly pigmented skin was exposed to sunlight. (wikipedia.org)
  • Genetic evidence also supports this notion, demonstrating that around 1.2 million years ago there was a strong evolutionary pressure which acted on the development of dark skin in early members of the genus Homo. (wikipedia.org)
  • Around 10-15 million skin lightening products are sold annually, with Japan being the major buyer. (wikipedia.org)
  • damage
  • A broad spectrum sunscreen with ecamsule, avobenzone and octocrylene significantly reduces the skin damage associated with UV exposure in human subjects. (wikipedia.org)
  • found
  • Hydroquinone-induced exogenous ochronosis was found in 1975 by Findlay, who observed the condition in patients who used skin lightening creams containing the compound. (wikipedia.org)
  • dark skin
  • the relationship between folate breakdown induced by ultraviolet radiation and reduced fitness as a failure of normal embryogenesis and spermatogenesis led to the selection of dark skin. (wikipedia.org)
  • The effect of sunlight on folic acid levels has been crucial in the development of dark skin. (wikipedia.org)
  • black
  • Symptoms include: yellow-brown, banana-shaped fibers caviar-like papules brown-grey or blue-black hyper-pigmentation The majority of the lesions will be seen on areas of the body that get the most sun. (wikipedia.org)
  • surface
  • This usually occurs in areas where connective tissue is thick (joints, tympanic membrane) or close to the surface of the skin (thenar and hypothenar eminences and the sides of the fingers). (wikipedia.org)
  • body
  • Because it interfaces with the environment, skin plays an important immunity role in protecting the body against pathogens and excessive water loss. (wikipedia.org)
  • The skin is the largest organ in the human body. (wikipedia.org)
  • seen
  • Uncommon side effects (with prolonged therapy) include skin discolouration and autoimmune disorders that are not seen with other drugs in the class. (wikipedia.org)
  • Skin: The pigment is deposited throughout the skin but only becomes apparent in certain locations where the concentration is great enough to be seen clinically. (wikipedia.org)
  • cancer
  • UVA rays cause wrinkling and may have some role in development of skin cancer. (wikipedia.org)
  • In studies done in mice it reduces the formation of UV induced pyrimidine dimers and delays the onset of skin cancer. (wikipedia.org)
  • A mouse study shows that it does not increase the probability of promoting skin cancer. (wikipedia.org)