Poison oak grows on a trail near Britt Gardens in Jacksonville. - Photo by Julia Moore

The hills are alive

Instead, Edwards spent days in her bathtub after a painful and embarrassing introduction to one of the region’s most pervasive and too-often problematic plants: poison oak.
“It’s just ubiquitous,” says Edwards, a 60-year-old former hike leader for the Sierra Club’s Rogue Group. “You can’t go anywhere without running into it.”
Immersed in a baking-soda solution waiting for the livid rash of liquid-filled pustules to subside, Edwards nearly decided to sell the property she had just purchased. That was 25 years ago, and Edwards still hasn’t sold. But she preaches and practices vigilance around poison oak’s deceptively ordinary-looking leaves, stems and roots — all sources of the oil that triggers an immune-system response in as much as 75 percent of western Oregon’s population.
When poison oak’s toxic chemicals, called urushiols, contact human skin, the body’s T cells spring into action. Attempting to keep the foreign substance at bay, these white blood cells actually give rise to the red, swollen, itchy, oozy rash typical of poison oak. The condition physicians call “contact dermatitis” — often minor skin inflammation in response to any irritant — can be all but debilitating when the cause is poison oak.
“The over-the-counter, topical cortisones just aren’t strong enough,” says Dr. Kent DeYarman, a Medford allergist, explaining that prescription creams or oral versions of the steroid are the only effective treatments for poison-oak rash. Some household remedies, such as soaking in a solution of Epsom salts, may alleviate itching, but they don’t accelerate healing, he adds.
The first line of defense is plain, old soap and water. It takes between 45 minutes and an hour for poison-oak oils to bind to human skin, after which they can’t be washed off.
DeYarman says anyone working outdoors around known sources of poison oak should take regular breaks to change clothes and shower. Hikers should pack a jug of wash water and soap with their gear, he says. Many hiking guides and sources of regional recreation information note prevalence of poison oak.
“Table Rocks (are) just covered with it,” says DeYarman.
True to the plant’s name, oak savannah at Southern Oregon’s middle elevations is prime habitat. But the native plant, which displays some of the area’s most vibrant orange and red autumnal hues, thrives in any wooded or shrubby areas. Even city-owned parks, such as Medford’s Prescott Park and Ashland’s iconic Lithia Park, harbor their share of poison oak.
This year’s cool, wet spring seems to have spurred poison oak to particularly lush growth, says Edwards. In her neck of the woods, heavily grazed for a century or so, poison oak has virtually pushed out other vegetation, she adds.
“The cattle didn’t eat it, so it’s like it went crazy,” she says. “It’s really hardy anyway.”
The concentration of toxic oils and chances of exposure are highest around poison-oak leaves that have been torn or bruised, namely by mowing and weed-eating, according to an article on DeYarman’s website (www.oregonallergy.com). But the persistent plant also penetrates protective clothing.
Edwards dismissed the small scratch on her shin when a twig poked through the light pair of pants she wore one day in May to walk her dog. Careful avoidance of poison oak had kept Edwards rash-free for more than two decades, so she didn’t recognize initial symptoms of exposure in the few days to follow.
“I started feeling really weird ... almost feverish.”
The insignificant scratch engendered telltale, red bumps that erupted even on Edwards’ face. Because outbreaks typically develop over one to seven days — sometimes as long as 14 — it’s often difficult to pinpoint time and location of poison-oak exposure, according to DeYarman’s website. And exposure can recur if oils remain on items such as shoes, tools, cameras and hunting and fishing gear that weren’t decontaminated. Pets often are blamed for spreading poison-oak oil from their fur to owners’ skin.
Despite infrequent reports of poison-oak reactions that require hospital care, the allergy is never life-threatening, says DeYarman, and the choice to seek medical assistance largely is determined by one’s own “misery index.” While the nationwide rate of poison-oak allergy is about 15 percent, he adds, locally “it’s much, much higher just because it’s so prevalent.”
Based on her recent run-in, Edwards is convinced that long lapses between poison-oak exposure don’t diminish the toxin’s effects. And anyone who claims immunity, she says, hasn’t spent enough time in Southern Oregon’s outdoors.

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