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For information on urushiol poisoning, see Urushiol-induced contact dermatitis
Urushiol-induced contact dermatitis

Urushiol-induced contact dermatitis is the medical name given to allergy rashes produced by the oil urushiol, which is contained in various plants, including the plants of the genus Toxicodendron , as well as other plants in the family Anacardiaceae , and also unrelated plants such as Ginkgo biloba....
.


Urushiol is an organic oil toxin
Toxin

A toxin is a poisonous substance produced by living cells or organisms. For a toxic substance not produced by living organisms, "toxicant" is the more appropriate term, and "toxics" is an acceptable plural....
 found in plants of the Family
Linnaean taxonomy

Linnaean taxonomy is a method of classifying living things, originally devised by Carolus Linnaeus , although it has changed considerably since his time....
 Anacardiaceae
Anacardiaceae

Anacardiaceae is a Family of flowering plants bearing fruits that are drupes and in some cases producing urushiol, an Irritation. Its 82 genera include several of economic importance....
, especially Toxicodendron
Toxicodendron

Toxicodendron is a genus of woody trees, shrubs and vines in the Anacardiaceae or Sumac Family, including poison ivy, poison oak, and the lacquer tree....
 spp. (e.g. poison oak
Poison oak

The name Poison oak can refer to either of two species of the genus Toxicodendron that grow in North America:* Toxicodendron diversilobum, Western Poison-oak, , found only on the Pacific Coast of North America, ranging from southern Canada to Baja California...
, poison ivy
Poison ivy

Toxicodendron radicans is a plant in the family Anacardiaceae. The name is sometimes spelled "Poison-ivy" in an attempt to indicate that the plant is not a true Ivy ....
, and poison sumac
Poison Sumac

Poison sumac is a woody shrub or small tree growing to 7 m tall. All parts of the plant contain a resin called urushiol that causes skin and mucous membrane irritation to humans....
). It causes an allergic skin
Skin

The skin is the outer covering of the body, also known as the epidermis. It is the largest organ of the integumentary system made up of multiple layers of epithelial biological tissue, and guards the underlying muscles, bones, ligaments and organ s....
 rash on contact, known as urushiol-induced contact dermatitis
Urushiol-induced contact dermatitis

Urushiol-induced contact dermatitis is the medical name given to allergy rashes produced by the oil urushiol, which is contained in various plants, including the plants of the genus Toxicodendron , as well as other plants in the family Anacardiaceae , and also unrelated plants such as Ginkgo biloba....
. The name comes from the Japanese
Japanese language

IPA: [n?iho?go] is a language spoken by over 130 million people in Japan and in Japanese emigrant communities. It is related to the Ryukyuan languages....
 word urushi, which denotes a lacquer
Lacquer

In a general sense, lacquer is a clear or coloured varnish that dries by solvent evaporation and often a curing process as well that produces a hard, durable finish, in any sheen level from ultra matte to high Gloss and that can be further polished as required....
 produced in East Asia
East Asia

East Asia is a subregion of Asia that can be defined in either Geography or cultural terms. Geography and geopolitically, it covers about 12,000,000 km?, or about 28 percent of the Asian continent, about 15 percent bigger than the area of Europe, though some categorize Tibet, Xinjiang, and Mongolia as Central Asia....
 from the sap of kiurushi trees (Lacquer Tree).






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Encyclopedia


For information on urushiol poisoning, see Urushiol-induced contact dermatitis
Urushiol-induced contact dermatitis

Urushiol-induced contact dermatitis is the medical name given to allergy rashes produced by the oil urushiol, which is contained in various plants, including the plants of the genus Toxicodendron , as well as other plants in the family Anacardiaceae , and also unrelated plants such as Ginkgo biloba....
.


Urushiol is an organic oil toxin
Toxin

A toxin is a poisonous substance produced by living cells or organisms. For a toxic substance not produced by living organisms, "toxicant" is the more appropriate term, and "toxics" is an acceptable plural....
 found in plants of the Family
Linnaean taxonomy

Linnaean taxonomy is a method of classifying living things, originally devised by Carolus Linnaeus , although it has changed considerably since his time....
 Anacardiaceae
Anacardiaceae

Anacardiaceae is a Family of flowering plants bearing fruits that are drupes and in some cases producing urushiol, an Irritation. Its 82 genera include several of economic importance....
, especially Toxicodendron
Toxicodendron

Toxicodendron is a genus of woody trees, shrubs and vines in the Anacardiaceae or Sumac Family, including poison ivy, poison oak, and the lacquer tree....
 spp. (e.g. poison oak
Poison oak

The name Poison oak can refer to either of two species of the genus Toxicodendron that grow in North America:* Toxicodendron diversilobum, Western Poison-oak, , found only on the Pacific Coast of North America, ranging from southern Canada to Baja California...
, poison ivy
Poison ivy

Toxicodendron radicans is a plant in the family Anacardiaceae. The name is sometimes spelled "Poison-ivy" in an attempt to indicate that the plant is not a true Ivy ....
, and poison sumac
Poison Sumac

Poison sumac is a woody shrub or small tree growing to 7 m tall. All parts of the plant contain a resin called urushiol that causes skin and mucous membrane irritation to humans....
). It causes an allergic skin
Skin

The skin is the outer covering of the body, also known as the epidermis. It is the largest organ of the integumentary system made up of multiple layers of epithelial biological tissue, and guards the underlying muscles, bones, ligaments and organ s....
 rash on contact, known as urushiol-induced contact dermatitis
Urushiol-induced contact dermatitis

Urushiol-induced contact dermatitis is the medical name given to allergy rashes produced by the oil urushiol, which is contained in various plants, including the plants of the genus Toxicodendron , as well as other plants in the family Anacardiaceae , and also unrelated plants such as Ginkgo biloba....
. The name comes from the Japanese
Japanese language

IPA: [n?iho?go] is a language spoken by over 130 million people in Japan and in Japanese emigrant communities. It is related to the Ryukyuan languages....
 word urushi, which denotes a lacquer
Lacquer

In a general sense, lacquer is a clear or coloured varnish that dries by solvent evaporation and often a curing process as well that produces a hard, durable finish, in any sheen level from ultra matte to high Gloss and that can be further polished as required....
 produced in East Asia
East Asia

East Asia is a subregion of Asia that can be defined in either Geography or cultural terms. Geography and geopolitically, it covers about 12,000,000 km?, or about 28 percent of the Asian continent, about 15 percent bigger than the area of Europe, though some categorize Tibet, Xinjiang, and Mongolia as Central Asia....
 from the sap of kiurushi trees (Lacquer Tree). The oxidation and polymerization of urushiol in the tree's sap in the presence of moisture allows it to form a hard lacquer
Lacquer

In a general sense, lacquer is a clear or coloured varnish that dries by solvent evaporation and often a curing process as well that produces a hard, durable finish, in any sheen level from ultra matte to high Gloss and that can be further polished as required....
, which is used to produce traditional Chinese and Japanese
Japan

Japan is an island country in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, People's Republic of China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south....
 lacquerwares.

Urushiol is a yellow liquid with a boiling point of 200-210 °C. It is miscible in alcohol and ether, but nearly immiscible in water. Chemically, urushiol is a mixture of several closely related organic compound
Organic compound

An organic compound is any member of a large class of chemical compounds whose molecules contain carbon. For historical reasons discussed below, a few types of compounds such as carbonates, simple oxides of carbon and cyanides, as well as the allotropes of carbon, are considered Inorganic compound....
s. Each consists of a catechol substituted with an alkyl
Alkyl

An alkyl is a univalent Radical consisting of carbon and hydrogen atoms, arranged in a chain. The Alkyls form homologous series with the general formula CnH2n+1....
 chain that has 15 or 17 carbon atoms. The alkyl group may be saturated
Saturation (chemistry)

In chemistry, saturation has five different meanings:#In physical chemistry, saturation is the point at which a solution of a substance can dissolve no more of that substance and additional amounts of it will appear as a Precipitation ....
 or unsaturated; urushiol oil is a mixture of saturated and unsaturated molecules. The mixture varies with the vegetative bspecies. Whereas Western poison oak urushiol contains chiefly catechols with C17 side chains, poison ivy
Poison ivy

Toxicodendron radicans is a plant in the family Anacardiaceae. The name is sometimes spelled "Poison-ivy" in an attempt to indicate that the plant is not a true Ivy ....
 and poison sumac yield mostly catechols with C15 side chains. The allergic reaction is dependent on the degree of unsaturation of the alkyl
Alkyl

An alkyl is a univalent Radical consisting of carbon and hydrogen atoms, arranged in a chain. The Alkyls form homologous series with the general formula CnH2n+1....
 chain. Less than half of the general population reacts with the saturated urushiol alone, but over 90% react with urushiol containing at least two degrees of unsaturation (double bonds).
Urushiol
R = (CH2)14CH3 or
R = (CH2)7CH=CH(CH2)5CH3 or
R = (CH2)7CH=CHCH2CH=CH(CH2)2CH3 or
R = (CH2)7CH=CHCH2CH=CHCH=CHCH3 or
R = (CH2)7CH=CHCH2CH=CHCH2CH=CH2 and others


See also


  • Burow's solution
    Burow's solution

    Burow's solution is a pharmacological preparation made of aluminium acetate dissolved in water. It was invented in the mid-1800s by Karl August Burow, an ophthalmologist....
    , for treating the toxin
  • Bentoquatam
    Bentoquatam

    Bentoquatam is a topical medication intended to act as a shield against exposure to the irritating substance urushiol, found in plants such as poison ivy or poison oak....
    , a barrier creme
  • Hapten
    Hapten

    A hapten is a small molecule which can elicit an immune response only when attached to a large carrier such as a protein; the carrier may be one which also does not elicit an immune response by itself....
  • Western Poison-oak
    Western Poison-oak

    Toxicodendron diversilobum is a plant best known for its ability to cause allergic rashes after contact. Western Poison-oak is found only on the West Coast of the United States of the United States and of Canada....
  • Pistachio
    Pistachio

    The pistachio is a small tree native to mountainous regions of Iran, Turkmenistan, Turkey and western Afghanistan, that produces an important nut #Culinary definition and uses....
  • Anti-itch drug
  • Anacardic acid
    Anacardic acid

    Anacardic acids are chemical compounds found in the shell of the cashew nut . As they are closely related to urushiol, they also cause an allergic skin rash on contact, known as urushiol-induced contact dermatitis....


Line notes


External links

  • at Wayne's Word