Problems with poison ivy

Wednesday, June 1, 2016

Randy has been sitting quietly on his couch all weekend, watching a marathon of his favorite western movies on TV. When his alarm rings at 5 a.m. Monday morning, he is surprised to find a rash from poison ivy making his arm uncontrollably itchy.

Without even going outside, Randy has managed to be affected by the nightmare of anyone allergic. How did that happen? Karen Hickman, Oklahoma State University range ecology and invasive species professor in the department of natural resource ecology and management, explains.

“One myth about poison ivy is the belief you can get poison ivy just by being near the plants. Well, that's not totally true,” she said. “In this particular scenario, maybe Randy let his dog out, who trampled through a patch, breaking open a leaf or two and getting some of the poisonous resin on its fur. Randy pets the dog, and voila.”

The poisonous part of poison ivy, urushiol, is a very oily resin that remains inside the leaves unless the plant is damaged or bruised. It is possible to touch an unblemished poison ivy plant and not have a reaction, but just the slightest damage, maybe caused from walking through a patch of the plant or a tiny insect making a tiny bite in the leaf, can cause leakage.

Other common ways of getting the poison ivy rash from coming in contact with the oily resin include touching contaminated garden tools, clothing, bicycles or pets, as well as inhaling smoke from burning poison ivy.

“The most minute amount can cause a reaction,” Hickman said. “When that urushiol comes in contact with your skin, it usually takes about 10 minutes before it penetrates deep enough to do any damage.”

If someone were to knowingly come in contact with the plant, that 10-minute window is important. It is suggested to immediately wash the area with cold water and a detergent for at least 10 minutes to remove the resin.

However, usually symptoms will not show themselves until 24 hours to 48 hours after initial contact. Those who indirectly come in contact with the plant, from clothes, garden tools, gloves, boots or even pets, can be in for a rude awakening.

“There are instances where people have gotten exposure from contaminated garden tools that have been locked up in a garden shed for over three years,” Hickman said. “The poisonous substance can remain active on clothing for up to one year, so it's a good idea to be careful with anything you think may have some that oil from poison ivy.”

Another myth is that ooze from blisters spread the rash. In fact, the fluid from the blisters does not contain urushiol.

“Once you notice a rash or blisters, it is best to apply a topical cream to fight the itch,” Hickman said. “It’s also a good idea to wash any clothes, bed sheets or anything else that you may have come in contact with.”