Toxicodendron

Toxicodendron is a genus of flowering plants in the family Anacardiaceae that includes several species known for causing contact dermatitis. Native to temperate regions of Asia and North America, these plants range from woody shrubs to climbing vines. The genus also includes Toxicodendron vernicifluum, the lacquer tree, which is cultivated for urushi lacquer in East Asia.

Notable members include poison ivy (Toxicodendron radicans), poison oak (Toxicodendron diversilobum and Toxicodendron pubescens), and poison sumac (Toxicodendron vernix). They are typically woody plants or vines with compound leaves and produce small greenish flowers, followed by berries that persist into autumn and may be dispersed by birds.

Urushiol and dermatitis: All Toxicodendron species contain urushiol oils in sap, leaves, stems, and fruit. Contact with urushiol can trigger a delayed-type hypersensitivity reaction, causing itching, redness, swelling, and blistering. Reactions may arise from direct contact or from contaminated clothing or tools, and smoke from burned plants can spread urushiol.

Ecology and management: In various habitats, Toxicodendron species provide seasonal cover and berries for wildlife. Prevention focuses on avoiding contact, wearing protective clothing, and washing exposed skin with soap and water as soon as possible. Contaminated clothing and gear should be washed separately, and appropriate cleaners can help remove urushiol from surfaces and equipment.