Toxicodendron Diversilobum

( Western Poison Oak, member of the Anacardiaceae family )

Allergenic Principles

Toxicodendrol, a phenolic oily resin, is present in all the poisonous species and contains a complex active principle, urushiol. Urushiol is distributed widely in the roots, stems, leaves, and fruit of the plant, but not in the flowers, pollen, or epidermis. Contact with the intact epidermis of the plant is harmless; dermatitis occurs only after contact with an injured plant or its sap. However, the epidermis of these plants is very fragile, and relatively minor friction or force such as high winds will injure the plant. The oleoresin may then collect on the surface as a black sticky sap. Dead and dried plants may be dangerous as well because their leaves and vines are also easily damaged. Because neither toxicodendrol nor urushiol is volatile, the dermatitis cannot be contracted through the air unless the plants are burned. Smoke from burning plants carries a substantial amount of the irritating oleoresin and may cause serious external and systemic reactions in susceptible individuals. Inhalation may produce severe trauma to the oral and nasal mucosa and lung tissue.

Other

Poison oak has blunt-tipped leaflets, hairy on both sides, that cluster in three leaflets per leaf stem. They are somewhat shorter (3 to 7 cm) than those of poison ivy. The plant commonly appears as either an unsupported, erect bush or a vine, and the center leaf of the cluster resembles an oak leaf. Western poison oak grows along the Pacific Coast from New Mexico to Canada, in low places, thickets and wooded slopes. Leaves generally bright, shiny green above, paler below. Fruits are small whitish berries.

Remedies