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June 14, 2014
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Extension Spotlight: Itching to know about poison oak?

Summer is upon us and with it comes a walk in the woods, enjoying the trees, observing the wildlife and possibly coming in contact with that pernicious plant — poison oak. Poison oak (Rhus diversiloba — you don’t see a Quercus here) is not really an oak.

The poison oak rash is caused by a chemical called urushiol. It is present in all parts of the plant: leaves, branches, roots, everything. I recently read an article that stated you only got the rash from contact with the leaves: wrong! Touch any part of the plant and the oil is absorbed into the skin. Urushiol is a poisonous substance, and the rash is the result of your body’s immune system fighting against it.

You also get poison oak by touching anyone or anything that has come in contact with the plant (animals, people, clothing, firewood). The rash doesn’t appear until after the oil is absorbed into your skin. Contact with the smoke from burning the plant can cause serious skin infections and inflammation of respiratory mucous membranes. Some people say they can contract the rash merely by being in proximity to poisonoak. Not sure ’bout that.

Some say that once you get the rash, you can’t spread it around by scratching. Balderdash! The explanation is that the “weeping” from your rash isn’t urushiol, it’s secreted by your body and you only have as much urushiol on you as received from when you came in contact with the agent. True enough, but through scratching and exposing the layers of skin that contains the chemical, you spread your body’s secretions as well as the urushiol.

First remedy. Stay away from the stuff. But if you do, here are some suggestions, and wrong remedies for removing the “itch.” There are dozens of treatments, some medically recommended, and others espoused by individuals experiencing the ill effects of poison oak. First and foremost, the first line of defense is to shower with plenty of some sort of cleaning agent (regular soap, bleach, Fels Naptha soap, laundry detergent) as soon as possible after being exposed: I concur.

Aloe Vera, vitamin E, Epsom salts, rubbing alcohol, antiperspirants, calamine lotion, baking soda, Tecnu, cortisone injections, hydrocortisone creams, oatmeal paste, vinegar, iodine, banana peels, Noxema pads, gasoline, ammonia, nail polish remover, hair spray ... the list goes on. One thing all of these “brews” have in common is that they attempt to speed up the drying process. It has also been suggested that by eating the leaves of the plant you will build up a resistance to the urushiol. Double balderdash!!

Remember that what works for one person may not work for someone else. You might be one of the lucky ones where the severity of your infections diminish or disappear over time. You could also be an unlucky one who suddenly finds themselves with an infection after years of seeming invincibility to the stuff. Poison oak: stay away if possible, and if not, most of us will likely suffer the consequences.

Steve Bowers is the forestry Extension agent for the Oregon State University Extension Service of Douglas County. He can be reached by email at or phone at 541-672-4461.

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The News-Review Updated Jun 14, 2014 10:46PM Published Jun 17, 2014 08:20AM Copyright 2014 The News-Review. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.