Urushiol in the context of "Cashew"

Lacquerware are objects decoratively covered with lacquer. Lacquerware includes small or large containers, tableware, a variety of small objects carried by people, and larger objects such as furniture and even coffins painted with lacquer. Before lacquering, the surface is sometimes painted with pictures, inlaid with shell and other materials, or carved. The lacquer can be dusted with gold or silver for example Hirameji and given further decorative treatments.

East Asian countries have long traditions of lacquer work, going back several thousand years in the cases of China, Japan and Korea. The best known lacquer, an urushiol-based lacquer common in East Asia, is obtained from the dried sap of Toxicodendron vernicifluum. Other types of lacquers are processed from a variety of plants and insects. The traditions of lacquer work in Southeast Asia, South Asia and the Americas are also ancient and originated independently. True lacquer is not made outside Asia, but some imitations, such as Japanning in Europe, or parallel techniques, are often loosely referred to a "lacquer."

Toxicodendron vernicifluum (formerly Rhus verniciflua), also known by the common name Chinese lacquer tree, is an Asian tree species of genus Toxicodendron native to China and the Indian subcontinent, and cultivated in regions of China, Japan and Korea. Other common names include poison sumac, Japanese lacquer tree, Japanese sumac, and varnish tree. The trees are cultivated and tapped for their toxic sap, which is used as a highly durable lacquer to make Chinese, Japanese, and Korean lacquerware.

The trees grow up to 20 metres tall with large leaves, each containing from 7 to 19 leaflets (most often 11–13). The sap contains the allergenic compound urushiol, which gets its name from this species' Japanese name urushi (urushi (漆)); "urushi" is also used in English as a collective term for all kinds of Asian lacquerware made from the sap of this and related Asian tree species, as opposed to European "lacquer" or Japanning made from other materials. Urushiol is also the oil found in poison ivy and poison oak that causes a rash.

Toxicodendron is a genus of flowering plants in the sumac family, Anacardiaceae. It contains trees, shrubs and woody vines, including poison ivy, poison oak, and the lacquer tree. The best-known members of the genus in North America are eastern poison ivy (T. radicans) and western poison oak (T. diversilobum), both ubiquitous throughout much of their respective region.

All members of the genus produce the skin-irritating oil urushiol, which can cause a severe allergic reaction known as urushiol-induced contact dermatitis. The resins of certain species native to Japan, China and other Asian countries, such as lacquer tree (T. vernicifluum) and wax tree (T. succedaneum), are used to make lacquer, and, as a byproduct of lacquer manufacture, their berries are used to make japan wax.

Poison ivy is a type of allergenic plant in the genus Toxicodendron native to Asia and North America. Formerly considered a single species, Toxicodendron radicans, poison ivies are now generally treated as a complex of three separate species: T. radicans, T. rydbergii, and T. orientale. They are variable in appearance and habit, and despite its common name, it is not a true ivy (i.e., Hedera), but rather a member of the cashew and pistachio family (Anacardiaceae).

Though T. radicans is commonly eaten by many animals and the seeds are consumed by birds, poison ivy is most often thought of as an unwelcome weed. It is well known for causing urushiol-induced contact dermatitis, an itchy, irritating, and sometimes painful rash, in most people who touch them. The rash is caused by urushiol, a clear liquid compound in the plant's sap.

The Anacardiaceae, commonly known as the cashew family or sumac family, are a family of flowering plants, including about 83 genera with about 860 known species. Members of the Anacardiaceae bear fruits that are drupes and in some cases produce urushiol, an irritant. The Anacardiaceae include numerous genera, several of which are economically important, notably cashew (in the type genus Anacardium), mango, Chinese lacquer tree, yellow mombin, Peruvian pepper, sumac, smoke tree, marula, and cuachalalate. The genus Pistacia (which includes the pistachio and mastic tree) is now included, but was previously placed in its own family, the Pistaciaceae.

The cashew family is more abundant in warm or tropical regions, with only a few species living in the temperate zones. Mostly native to tropical Americas, Africa, and India. Pistacia and some species of Rhus can be found in southern Europe, Rhus species can be found in much of North America, and Schinus inhabits South America exclusively.

Toxicodendron vernix, commonly known as poison sumac, or swamp-sumach, is a woody shrub or small tree growing to 9 metres (30 feet) tall. It was previously known as Rhus vernix. This plant is also known as thunderwood, particularly where it occurs in the southern United States.

Like its toxic relatives poison ivy and poison oak, all parts of the plant contain a resin called urushiol, which causes skin and mucous membrane irritation to humans. When the plant is burned, inhalation of the smoke may cause the rash to appear on the lining of the lungs, causing extreme pain and possibly fatal respiratory difficulty.

Urushiol-induced contact dermatitis (also called Toxicodendron dermatitis or Rhus dermatitis) is a type of allergic contact dermatitis caused by the oil urushiol found in various plants, most notably sumac family species of the genus Toxicodendron: poison ivy, poison oak, poison sumac, and the Chinese lacquer tree. The name is derived from the Japanese word for the sap of the Chinese lacquer tree, urushi. Other plants in the sumac family (including mango, pistachio, the Burmese lacquer tree, the India marking nut tree, and the cashew) also contain urushiol, as do unrelated plants such as Ginkgo biloba.

As is the case with all contact dermatitis, urushiol-induced allergic rashes are a Type IV hypersensitivity reaction, also known as delayed-type hypersensitivity. Symptoms include itching, inflammation, oozing, and, in severe cases, a burning sensation. Additionally, smoke from burning plant matter may be toxic.