What is the pathophysiology of allergic contact dermatitis due to Anacardiaceae plants?

Updated: Jun 10, 2021
  • Author: Glen H Crawford, MD; Chief Editor: Dirk M Elston, MD  more...
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Urushiol, the allergenic oleoresin of Toxicodendron plants, derives its name from the Japanese word kiurushi, the sap of the Japanese lacquer tree (Tverniciflua). Urushiols from poison ivy and poison oak contain pentadecylcatechols, which are the primary sensitizers. Catechols are soluble in rubber; consequently, rubber gloves are not protective against these allergens.

Particles suspended in smoke can carry urushiol. Nonleaf portions of the plant can induce dermatitis, even in the winter. Blister fluid does not contain urushiol; the vesicles and bullae of dermatitis due to poison ivy or other Anacardiaceae plants do not contain the allergens. Therefore, breaking these blisters does not cause the rash to spread.

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