Poison Ivy, A 鈥楩amiliar Stranger鈥 That Could Ruin Your Summer
Microbiologist John Jelesko has learned not to take any chances when he touches poison ivy. (Courtesy of John Jelesko)
It was a close encounter in 2012 that made microbiologist John Jelesko take an interest in poison ivy.
was cutting up a downed tree with an electric chainsaw. What he didn鈥檛 realize was that his power cable had been dragging through poison ivy. So, at the end of the day, as he coiled the cord around his palm and elbow, he inadvertently launched a career-bending science experiment.
鈥淲ithin 48 hours, I had your classic case of poison ivy on my arm. And as a scientist, I said, 鈥楾his is interesting, how bad can it be? I鈥檒l just leave this untreated,鈥欌 he recalled, sheepishly. 鈥淚n about two weeks, I had learned just how uncomfortable poison ivy rash could be.鈥
Uncomfortable sounds like an understatement. Jelesko said he barely slept while fighting the urge to 鈥渃law my itching flesh off.鈥 Eventually, he went to his family doctor, who prescribed oral steroids.
The experience sparked into a plant he calls a 鈥渇amiliar stranger.鈥 He has studied the chemical, urushiol, that triggers that telltale rash and the plant鈥檚 biology overall.
The tricky thing about avoiding poison ivy, Jelesko said, is the plant is highly adaptable and can take many different forms in different environments.
鈥淚t鈥檚 remarkable,鈥 he said, with a laugh. 鈥淭here鈥檚 just an enormous amount of things with this plant that are currently unknown.鈥
Here, he offers insights into how to recognize Toxicodendron radicans, the scientific name of the plant, before you risk touching it 鈥 and what to do if it鈥檚 too late.
Know The Leaf Shapes
The axiom 鈥渓eaves of three, let it be鈥 is accurate, said Jelesko, but those leaves can come in many shapes, even on the same plant. You鈥檙e safe if the plant has thorns 鈥 poison ivy doesn鈥檛 鈥 but it does sometimes have little white berries.
Can You Recognize This Leaf?
All of these are the same pesky, rash-inducing plant.聽Poison ivy leaves sometimes appear with jagged or lobed edges, and sometimes smooth.
(Clockwise from top left) Poison ivy with smooth edges; jagged edges; round leaves; notched leaves. All pictures were taken on a trail in a state park on Tennessee鈥檚 Cumberland Plateau. (Blake Farmer/WPLN)
Same Plant, Many Forms
Poison ivy can present as a vine or a shrub. When mature vines climb up a tree, their shape can even mimic that of the host tree. Simply pushing aside an innocent-seeming branch could make the passer-by pay a few days later, when a rash begins to well up.
Jelesko鈥檚 latest research, which is not yet published, finds that in cities poison ivy tends to grow as a climbing vine, whereas out in the forest, most of the plants are ground-creeping vines. And poison ivy is much more prevalent in 鈥渓andscapes modified by humans鈥 than out in the middle of the woods.
Some poison ivy vines can be downright awe-inspiring in their size, like the one in this .
Poison ivy can grow as a creeping vine on the ground. (Blake Farmer/WPLN)
Or it can grow as a shrub. (Angela Roberts/Flickr)
Poison ivy can take over a dead tree, like this one on the Virginia Tech golf course. From afar, it looks like it could be an evergreen. Up close, it becomes clear that this is a nightmare of nature. (Courtesy of John Jelesko)
What To Do When The Tricky Plant Wins 鈥
If you think you鈥檝e touched a plant, or unfortunately know you have, follow these tips to alleviate the problem. Of course, prevention is the best route. For John Jelesko, he now dons a protective Tyvek suit and two pairs of gloves when he wallows in poison ivy. Your last line of defense:
- Wash with soap and water within a few hours. This tends to prevent an outbreak in most people.
- Keep an eye out for a streaky, red rash in the first few days, especially if you鈥檝e previously had a reaction to poison ivy. For poison ivy newbies, the rash could take a week to develop. Repeat customers can start breaking out in a day or two. Rather than building immunity, multiple exposures can make someone more sensitive, priming the immune system to produce a more 鈥渞obust鈥 response, Jelesko said.
- When a rash appears, soothing it with anti-itch or corticosteroid cream.
- And if it gets really bad, go to the doctor, especially if the rash involves sensitive areas like the mouth or genitals.
- But steroids and anti-itch medicine doesn鈥檛 solve the whole problem. Afound that part of the body鈥檚 response involves a protein known for inducing inflammation on the skin, 鈥渆xciting鈥 the nerve fibers in the skin and sending itchy signals to the brain. An antibody that counteracts the protein is currently in a clinical trial with humans to determine potential side effects.
- If your pup came along with you on the outing that exposed you to poison ivy, never fear. Dogs are not allergic 鈥 but their fur can definitely hold the oil and transfer it to their owners, so pet your dog with caution after hiking past poison ivy. Scientists haven鈥檛 found many animals that break out like humans do, though lab mice seem to be allergic enough for research.
This story is part of a partnership that includes , and Kaiser Health News.