What does urushiol mean?
Urushiol is the collective name for a group of oily chemical compounds found in the sap of lacquer trees and related plants, including poison ivy, poison oak, and poison sumac. It is the principal allergen responsible for allergic contact dermatitis from those plants. When urushiol reaches the skin, it can bind to skin proteins and provoke an immune response in sensitized people, producing redness, itching, swelling, and sometimes severe blistering. The allergen may remain on clothing, tools, or animal fur and can be transferred to other people indirectly. Exposure to urushiol is a common cause of seasonal rashes among hikers, gardeners, and outdoor workers, making knowledge of it useful for recognizing and avoiding symptoms. Although commonly associated with poison ivy, urushiol is also found in other members of the Anacardiaceae family. The word belongs chiefly to scientific and medical vocabulary and is not regionally restricted.
nounA mixture of oily catechol compounds found in the sap of lacquer trees and related plants, especially members of the genus Toxicodendron. Urushiol is the principal allergen responsible for poison ivy, poison oak, and poison sumac contact dermatitis.
- The oily allergenic constituents of lacquer-tree sap and other related plants, collectively responsible for most cases of poison ivy, poison oak, and poison sumac dermatitis.
"Urushiol on the skin can trigger an intense, blistering allergic reaction within hours or days."
"The guide warned hikers that urushiol could remain on clothing and camping equipment after contact with poison ivy."
"Her dermatologist suspected that the rash had been caused by exposure to urushiol, the oily allergen in poison oak."
Rarely used; technical contexts may pluralize it when referring to the individual oily compounds collectively known as urushiol.
"Researchers compared the allergenic activity of several urushiols isolated from lacquer sap."
Poison ivy’s notorious itch has a microscopic culprit: urushiol can turn a brief encounter with the plant into weeks of dermatitis.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of urushiol
The name combines Japanese urushi, meaning lacquer or lacquer-tree sap, with the chemical suffix -ol, associated with alcohols and hydroxyl groups. It was adopted in scientific usage for the oily catechol compounds found in lacquer sap. Those compounds were later recognized as the major causes of allergic dermatitis caused by poison ivy and related plants.
Related word forms
How urushiol is actually used
Urushiol is primarily used in chemistry, toxicology, and dermatology. It is normally treated as a mass noun when referring collectively to the allergenic compounds in plant sap.
Easily confused with urushiol
Urushiol causes allergic contact dermatitis after exposure to certain plants, whereas urticaria is a raised, itchy rash commonly described as hives and may have many causes.