Freckle
Encyclopedia
For other uses of the word, see Freckles (disambiguation)
.
Freckles are clusters of concentrated melanin
which are most often visible on people with a fair complexion
. A freckle is also called an "ephelis". Freckles do not have an increased number of melanin producing cells (melanocytes). This is in contrast to lentigines and moles
.
Freckles can be found on anyone no matter their genetic background; however, having freckles is gene
tic and is related to the presence of the dominant melanocortin-1 receptor MC1R
gene variant. The formation of freckles is triggered by exposure to sunlight
. The exposure to UV-B radiation activates melanocytes to increase melanin production, which can cause freckles to become darker.
Freckles are predominantly found on the face, although they may appear on any skin exposed to the sun, such as the shoulders. Freckles are rare on infant
s, and more commonly found on child
ren before puberty
.
Upon exposure to the sun, freckles will reappear if they have been altered with creams
or laser
s and not protected from the sun, but do fade with age in some cases. They can also be treated with citric acid.
Freckles are not a skin disorder, but people with freckles generally have a lower concentration of photoprotective melanin and are therefore more susceptible to the harmful effects of UV-radiation. It is suggested that they avoid overexposure and use sunscreen
.
Liver spots (also known as sun spots and Lentigines) are freckles that may not fade in the winter. Rather, they form after years of exposure to the sun. Lentigines are more common in older people.
Freckles (disambiguation)
Freckles are clusters of concentrated melanin which are most often visible on people with a fair complexion.Freckles may also refer to:* Freckles , a 1904 American novel* Freckles , a 1960 American film based on the novel...
.
Freckles are clusters of concentrated melanin
Melanin
Melanin is a pigment that is ubiquitous in nature, being found in most organisms . In animals melanin pigments are derivatives of the amino acid tyrosine. The most common form of biological melanin is eumelanin, a brown-black polymer of dihydroxyindole carboxylic acids, and their reduced forms...
which are most often visible on people with a fair complexion
Complexion
Complexion refers to the natural color, texture, and appearance of the skin, especially that of the face.-History:The word "complexion" is derived from the Late Latin complexi, which initially referred in general terms to a combination of things, and later in physiological terms, to the balance of...
. A freckle is also called an "ephelis". Freckles do not have an increased number of melanin producing cells (melanocytes). This is in contrast to lentigines and moles
Mole (skin marking)
A melanocytic nevus is a type of lesion that contains nevus cells .Some sources equate the term mole with "melanocytic nevus". Other sources reserve the term "mole" for other purposes....
.
Biology
Gene
A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...
tic and is related to the presence of the dominant melanocortin-1 receptor MC1R
Melanocortin 1 receptor
The melanocortin 1 receptor , also known as melanocyte-stimulating hormone receptor , melanin-activating peptide receptor, or melanotropin receptor, is a G protein-coupled receptor which binds to a class of pituitary peptide hormones known as the melanocortins, of which include adrenocorticotropic...
gene variant. The formation of freckles is triggered by exposure to sunlight
Sunlight
Sunlight, in the broad sense, is the total frequency spectrum of electromagnetic radiation given off by the Sun. On Earth, sunlight is filtered through the Earth's atmosphere, and solar radiation is obvious as daylight when the Sun is above the horizon.When the direct solar radiation is not blocked...
. The exposure to UV-B radiation activates melanocytes to increase melanin production, which can cause freckles to become darker.
Freckles are predominantly found on the face, although they may appear on any skin exposed to the sun, such as the shoulders. Freckles are rare on infant
Infant
A newborn or baby is the very young offspring of a human or other mammal. A newborn is an infant who is within hours, days, or up to a few weeks from birth. In medical contexts, newborn or neonate refers to an infant in the first 28 days after birth...
s, and more commonly found on child
Child
Biologically, a child is generally a human between the stages of birth and puberty. Some vernacular definitions of a child include the fetus, as being an unborn child. The legal definition of "child" generally refers to a minor, otherwise known as a person younger than the age of majority...
ren before puberty
Puberty
Puberty is the process of physical changes by which a child's body matures into an adult body capable of reproduction, as initiated by hormonal signals from the brain to the gonads; the ovaries in a girl, the testes in a boy...
.
Upon exposure to the sun, freckles will reappear if they have been altered with creams
Cream (pharmaceutical)
A cream is a topical preparation usually for application to the skin. Creams for application to mucus membranes such as those of the rectum or vagina are also used. Creams may be considered pharmaceutical products as even cosmetic creams are based on techniques developed by pharmacy and...
or laser
Laser
A laser is a device that emits light through a process of optical amplification based on the stimulated emission of photons. The term "laser" originated as an acronym for Light Amplification by Stimulated Emission of Radiation...
s and not protected from the sun, but do fade with age in some cases. They can also be treated with citric acid.
Freckles are not a skin disorder, but people with freckles generally have a lower concentration of photoprotective melanin and are therefore more susceptible to the harmful effects of UV-radiation. It is suggested that they avoid overexposure and use sunscreen
Sunscreen
Sunblock is a lotion, spray, gel or other topical product that absorbs or reflects some of the sun's ultraviolet radiation on the skin exposed to sunlight and thus helps protect against sunburn...
.
Types of freckles
Ephelides is a genetic trait. It is used to describe a freckle which is flat, light brown or red, and fades in the winter. Ephelides are more common in those with light complexions, although they are found on people with a variety of skin tones. The regular use of sunblock can inhibit their development.Liver spots (also known as sun spots and Lentigines) are freckles that may not fade in the winter. Rather, they form after years of exposure to the sun. Lentigines are more common in older people.
See also
- Red hairRed hairRed hair occurs on approximately 1–2% of the human population. It occurs more frequently in people of northern or western European ancestry, and less frequently in other populations...
- Beauty markBeauty markA beauty mark or beauty spot is a euphemism for a type of dark facial mole, so named because such birthmarks are sometimes considered an attractive feature. Medically, such "beauty marks" are generally melanocytic nevus, more specifically the compound variant...
- Mole (skin marking)Mole (skin marking)A melanocytic nevus is a type of lesion that contains nevus cells .Some sources equate the term mole with "melanocytic nevus". Other sources reserve the term "mole" for other purposes....
- List of Mendelian traits in humans
- SunscreenSunscreenSunblock is a lotion, spray, gel or other topical product that absorbs or reflects some of the sun's ultraviolet radiation on the skin exposed to sunlight and thus helps protect against sunburn...
External links
- MedicineNet.com: Freckles
- eMedicine: Ephelides (Freckles). Free subscription required.