All three plants secrete a potent, irritating oil known as urushiol that causes blistering and intense itching once it penetrates the skin.
Urushiol oil or resin is found in the leaves, roots, and woody parts (i.e., vines and stems) of the poison ivy, oak, and sumac plants.
Leaves are bruised easily, especially in the spring, so even a gentle brush against a plant can cause the urushiol to seep out and onto the skin.
According to the American Academy of Dermatology, an estimated 85 percent of the population is allergic to the urushiol oil found in poison ivy, oak, and sumac.
It is possible for children who are highly reactive to urushiol to grow into adults who are barely sensitive to poison ivy, oak, or sumac, regardless of how many times they have been exposed to the plant oil.
Urushiol oil can be transmitted on clothing, pets, garden tools, shoes, or virtually anything that touches a plant.
Most children will not get a rash the very first time they are exposed to poison ivy, oak, or sumac, although this is when the sensitivity, or immune response, to urushiol develops.
Not everyone acquires an allergic sensitivity to urushiol, but in those that do, the next time they are exposed to the plant and urushiol penetrates the skin, a rash is inevitable.
There are several lotions and creams on the market that remove urushiol oil from the skin and can prevent further spreading of the rash if oil remains, or even prevent the rash entirely if applied early enough following exposure.
Rubbing (isopropyl) alcohol can also remove urushiol on both skin and household objects.
The sap of the jewelweed plant (Impatiens capensis) is thought to be helpful in binding to and removing urushiol from skin.
Burt's Bees Poison Ivy Soap) can be used to wash away urushiol.
If urushiol enters the respiratory tract, which typically happens when the plant is burned and the smoke is breathed in, it can be life threatening.
There are several topical skin creams on the market that contain bentoquatum, which forms a protective barrier designed to repel urushiol oil (e.g.
A full body shower is best to eliminate all traces of the urushiol and prevent re-exposure from undetected oil remaining on other parts of the body.
Again, water should be cool, as warm water will open pores and allow urushiol to penetrate the skin more quickly.
Other over-the-counter skin cleansers formulated to remove urushiol oil (e.g.
Tecnu, IvyStat, IvyCleanse) can also stop or lessen the severity of a rash if they are applied early enough following exposure (i.e., before the urushiol begins penetrating the skin).
The same goes for shoes and garden gloves, which are common culprits of harboring urushiol oil.
Pet fur can also carry urushiol oil into the home.
Pets are typically not sensitive to urushiol, but a dog or cat that seems to be experiencing symptoms of poison plant rash following exposure should be taken to the veterinarian for assessment.
Dead plants still contain urushiol and must be handled carefully during removal.
Mowing over the vines or plants can also send urushiol into the air and has the potential to cause a serious allergic reaction.
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