Most people get the rash from touching leaves, while gardening, hiking, or looking for a ball lost in the weeds. These encounters often result in a small rash on the hands, arms, or legs.
If you do anything that breaks the vines, stems, roots, and leaves you unleash large amount of the plant oil, urushiol, that causes the rash. The most serious rashes occur when people try to remove poison ivy without precautions, or weed-whack wearing shorts in a patch of poison ivy or oak.
Yes, the plant oil can be transferred from other things to your skin, so be wary of anything that might have been in contact with poison ivy or oak.
The urushiol oil is very stable if kept out of sunlight and weather. Museum specimens 60 years old have given people a rash.
We have a story about a young man who was exposed to large amounts of urushiol, slept in his sleeping bag, got a terrible rash – but got a rash almost as bad a year later from the same sleeping bag.
In Japan and other far-eastern countries urushiol oil from the Chinese Lacquer Tree, Toxicodendron vernicifluum, a close relative of our poison oak, ivy, and sumac, is used to create a lovely black finish.
There are numerous videos online about this art form, some showing people stirring large bowls of urushiol oil. The workers are not immune, just very careful.
And the fact that they can work closely with the oil and not get a rash indicates that the oil does not travel through the air – unless it is burned.
Most veterinarians say that animals don’t get the poison ivy and oak rash. And we know that goats are happy to eat lots of poison ivy happily.
However it is also true that most animals have fur that would protect their skin from direct contact with the plant, so there might be room for doubt.
But my dog, Walter, spotted above, lying in a patch of poison ivy, where his belly was not very protected with fur, never seemed to have a problem.
Never, ever burn poison ivy, poison oak, or poison sumac. Don’t burn the living plants to clear brush, don’t burn the dead parts.
The smoke can transmit the urushiol oil as little soot particles onto your skin and into your lungs.
Forest fire fighters, particularly in California, have been hospitalized from inhaling poison oak smoke, and in the east people have gotten equally sick from burning poison ivy.
About 15% of people are immune to the plant oil, and others can become immune. However, you can gain or lose immunity, so to assume you can’t get it if you never have before is not wise.
We have an email from mother and son gardeners who were always immune… until they weren’t.
Just like you can develop an allergy to certain foods in mid-life, you can develop an allergy to poison ivy.
Quite a few people (this writer included) seemed to find that as they were exposed to poison ivy more and more they became – not immune – but less sensitive and got rashes that were less of a problem.
But as we mention in the panel above, you can also become less immune over time.
A famous nature writer suggested this, but nobody should try it. For one thing, he might have been totally immune, and secondly: the rash does not affect the internal organs but does affect the mouth and the portal at the far end of the digestive system.
Many years ago they gave shots for poison ivy, but they were not very effective and they stopped being offered.
Recently new developments point toward a possible vaccine, but it is in testing at this time.
If you can’t avoid contact with the plants and keep getting a rash, check with an allergist.
Birds feed happily on the berries all through the winter, so it is a food source.
It holds the earth against erosion near the ocean and river banks. It keeps seaside areas from eroding by binding the soil with the roots, but also by discouraging people from walking in certain areas.
It has possible medical uses. We still understand little about the complex chemistry of nature. Someday, someone might discover an important human use for poison ivy and its cousins.
There are many other sites with solid information because these plant cause so much misery. Here some important other websites:
These site focus on poison ivy, but you can search for other resources for California’s Pacific poison oak, Atlantic poison oak, and poison sumac.
Here are 4 books that are well written and informative, with links to Alabris, an online book source.
The last of these is quite different: it is an exploration about many fascinating aspects of poison ivy that are not well known… and also mentions this website!
There are many other books (but also many more about Poison Ivy, the movie character).