Duke Medicine: Preventing, treating poison oak, poison ivy allergies

When a walk in the woods leaves you with red, itchy bumps, poison oak or poison ivy is often the culprit. Or, actually, the oily substance on the leaves -- oleoresin -- is to blame.

Dr. Stephanie Foley, a resident at Duke Family Medicine, explains that the bumps and itchiness are a person’s allergic reaction to the oleoresin from the poisonous plants.

“Like other allergies, each person’s immune system is different, so there is no rhyme or reason as to why some people are allergic to the plants while others are not,” Foley says.

So, what should you do if you know, or even think, you’ve come in contact with poison ivy or poison oak?

According to family medicine practitioner Dr. Brian Halstater, if you think you may have touched a poisonous plant or had an exposure to the oils, washing the area with soap and water within the first five to 10 minutes can prevent a reaction.

And when it comes to breaking down the oils and getting them off your skin, nothing has been proven to be more effective than good old soap and water.

It’s also a good idea to wash clothes that you suspect have had contact with the poisonous plants. Washing them immediately with soap and water will remove the oleoresin and prevent a future reaction when you wear them again.

Though there is a myth that the oils from the plants can stay harmful for a year, this is highly unlikely, says Foley. “However, the oil can stay intact after transfer, so that’s why you need to wash thoroughly immediately after contact.”