Poison Ivy...Outsmarting Poison Ivy and Its Cousins

What is poison ivy, poison oak, and poison sumac?

The Summer is upon us and so are those nasty rashes from brushing up against poisonous plants such as poison ivy, poison oak, and sumac. Approximately 85 percent of the population will develop an allergic reaction if exposed to poison ivy, oak or sumac, according to the American Academy of Dermatology.

Poison Ivy, Poison Oak, Poison Sumac

Usually, people develop a sensitivity to poison ivy, oak or sumac only after several encounters with the plants, sometimes over many years. However, sensitivity may occur after only one exposure.

The cause of the rash, blisters, and infamous itch is urushiol (pronounced oo-roo-shee-ohl), a chemical in the sap of poison ivy, oak and sumac plants. Because urushiol is inside the plant, brushing against an intact plant will not cause a reaction. But undamaged plants are rare.

Poison oak, ivy and sumac are very fragile plants, and stems or leaves broken by the wind or animals, and even the tiny holes made by chewing insects, can release urushiol.