Vitiligo is a disorder that causes the skin to lose its color. Specific causes are unknown but studies suggest a link to immune system changes.
Griseofulvin is an antifungal medication used to treat a number of types of dermatophytoses (ringworm). This includes fungal infections of the nails and scalp, as well as the skin when antifungal creams have not worked. It is taken by mouth.
Hyperpigmentation is the darkening of an area of skin or nails caused by increased melanin.
Hypopigmentation is characterized specifically as an area of skin becoming lighter than the baseline skin color, but not completely devoid of pigment. This is not to be confused with depigmentation, which is characterized as the absence of all pigment. It is caused by melanocyte or melanin depletion, or a decrease in the amino acid tyrosine, which is used by melanocytes to make melanin. Some common genetic causes include mutations in the tyrosinase gene or OCA2 gene. As melanin pigments tend to be in the skin, eye, and hair, these are the commonly affected areas in those with hypopigmentation.
Melasma is a tan or dark skin discoloration. Melasma is thought to be caused by sun exposure, genetic predisposition, hormone changes, and skin irritation. Although it can affect anyone, it is particularly common in women, especially pregnant women and those who are taking oral or patch contraceptives or hormone replacement therapy medications.
PUVA is an ultraviolet light therapy treatment for skin diseases: eczema, psoriasis, graft-versus-host disease, vitiligo, mycosis fungoides, large plaque parapsoriasis, and cutaneous T-cell lymphoma, using the sensitizing effects of the drug psoralen. The psoralen is applied or taken orally to sensitize the skin, then the skin is exposed to UVA.
Hydroquinone, also known as benzene-1,4-diol or quinol, is an aromatic organic compound that is a type of phenol, a derivative of benzene, having the chemical formula C6H4(OH)2. It has two hydroxyl groups bonded to a benzene ring in a para position. It is a white granular solid. Substituted derivatives of this parent compound are also referred to as hydroquinones. The name "hydroquinone" was coined by Friedrich Wöhler in 1843.
Tyrosinase is an oxidase that is the rate-limiting enzyme for controlling the production of melanin. The enzyme is mainly involved in two distinct reactions of melanin synthesis otherwise known as the Raper Mason pathway. Firstly, the hydroxylation of a monophenol and secondly, the conversion of an o-diphenol to the corresponding o-quinone. o-Quinone undergoes several reactions to eventually form melanin. Tyrosinase is a copper-containing enzyme present in plant and animal tissues that catalyzes the production of melanin and other pigments from tyrosine by oxidation. It is found inside melanosomes which are synthesized in the skin melanocytes. In humans, the tyrosinase enzyme is encoded by the TYR gene.
Methoxsalen, sold under the brand name Oxsoralen among others, is a medication used to treat psoriasis, eczema, vitiligo, and some cutaneous lymphomas in conjunction with exposing the skin to ultraviolet (UVA) light from lamps or sunlight. Methoxsalen modifies the way skin cells receive the UVA radiation, allegedly clearing up the disease. Levels of individual patient PUVA exposure were originally determined using the Fitzpatrick scale. The scale was developed after patients demonstrated symptoms of phototoxicity after oral ingestion of methoxsalen followed by PUVA therapy. Chemically, methoxsalen belongs to a class of organic natural molecules known as furanocoumarins. They consist of coumarin annulated with furan. It can also be injected and used topically.
Azelaic acid (AzA) is an organic compound with the formula HOOC(CH2)7COOH. This saturated dicarboxylic acid exists as a white powder. It is found in wheat, rye, and barley. It is a precursor to diverse industrial products including polymers and plasticizers, as well as being a component of a number of hair and skin conditioners. AzA inhibits tyrosinase.
A lentigo is a small pigmented spot on the skin with a clearly defined edge, surrounded by normal-appearing skin. It is a harmless (benign) hyperplasia of melanocytes which is linear in its spread. This means the hyperplasia of melanocytes is restricted to the cell layer directly above the basement membrane of the epidermis where melanocytes normally reside. This is in contrast to the "nests" of multi-layer melanocytes found in moles. Because of this characteristic feature, the adjective "lentiginous" is used to describe other skin lesions that similarly proliferate linearly within the basal cell layer.
Cysteamine is a chemical compound that can be biosynthesized in mammals, including humans, by the degradation of coenzyme A. The intermediate pantetheine is broken down into cysteamine and pantothenic acid. It is the biosynthetic precursor to the neurotransmitter hypotaurine.
Skin whitening, also known as skin lightening and skin bleaching, is the practice of using chemical substances in an attempt to lighten the skin or provide an even skin color by reducing the melanin concentration in the skin. Several chemicals have been shown to be effective in skin whitening, while some have proven to be toxic or have questionable safety profiles. This includes mercury compounds which may cause neurological problems and kidney problems.
Arbutin is a glycoside; a glycosylated hydroquinone extracted from the bearberry plant in the genus Arctostaphylos among many other medicinal plants, primarily in the family Ericaceae. Applied topically, it inhibits tyrosinase and thus prevents the formation of melanin. Arbutin is therefore used as a skin-lightening agent. Very tiny amounts of arbutin are found in wheat, pear skins, and some other foods. It is also found in Viburnum opulus and Bergenia crassifolia. Arbutin was also produced by an in vitro culture of Schisandra chinensis.
Depigmentation is the lightening of the skin or loss of pigment. Depigmentation of the skin can be caused by a number of local and systemic conditions. The pigment loss can be partial or complete. It can be temporary or permanent.
Mequinol, MeHQ or 4-methoxyphenol, is a phenol used in dermatology and organic chemistry.
Halo nevus is a mole that is surrounded by a depigmented ring or 'halo'.
Oral pigmentation is asymptomatic and does not usually cause any alteration to the texture or thickness of the affected area. The colour can be uniform or speckled and can appear solitary or as multiple lesions. Depending on the site, depth, and quantity of pigment, the appearance can vary considerably.
Nevus depigmentosus is a loss of pigment in the skin which can be easily differentiated from vitiligo. Although age factor has not much involvement in the nevus depigmentosus but in about 19% of the cases these are noted at birth. Their size may however grow in proportion to growth of the body. The distribution is also fairly stable and are nonprogressive hypopigmented patches. The exact cause of nevus depigmentosus is still not clearly understood. A sporadic defect in the embryonic development has been suggested to be a causative factor. It has been described as "localised albinism", though this is incorrect.
Rhododendrol (RD) also called 4-[(3R)-3-hydroxybutyl]phenol (systemic name), is an organic compound with the formula C10H14O2. It is a naturally occurring ingredient present in many plants, such as the Rhododendron. The phenolic compound was first developed in 2010 as a tyrosinase inhibitor for skin-lightening cosmetics. In 2013, after rhododendrol reportedly caused skin depigmentation in consumers using RD-containing skin-brightening cosmetics, the cosmetics were withdrawn from the market. The skin condition, caused by RD, is called RD-induced leukoderma. Rhododendrol exerts melanocyte cytotoxicity via a tyrosinase-dependent mechanism. It has been shown to impair the normal proliferation of melanocytes through reactive oxygen species-dependent activation of GADD45. It is now well established that rhododendrol is a potent tyrosinase inhibitor.
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