Hiker’s Itch : Poison Oak Flourishes in Area’s Forests, Making Escape to Nature a Risky Venture

Ranger Terry Austin has a warning for hikers, campers and anyone else who ventures into the woods these days: Life’s an itch.

The record winter rains have produced a bumper crop of poison oak from the Simi Hills to the Topatopa Mountains to city parks and barrancas. Enveloping hillsides, creeping onto trails, the noxious native plant “is everywhere,” Austin said.

All over Ventura County, dermatologists are seeing an increase in poison oak cases compared with this time last year.

“There are definitely more folks showing up with it,” said Dr. Paul Rehder of Oxnard. “They come in with blisters and bubbles and scratched areas on their legs, and the first question I ask is, ‘Where were you hiking or camping last weekend?’ ”

According to experts, forest users need to know more than just the conventional wisdom--”Leaves of three, let it be”--to emerge from the woods without a rash. For instance, the scalloped leaves, which have a satin sheen, don’t always come with three lobes. Although it grows prolifically in stream-fed canyons, poison oak can also be present in chaparral. And the plant doesn’t always take the same form. In local forests, poison oak can be a vine, ground cover or shrub.

“It’s really deceptive,” said Suzanne Goode, an ecologist for the state Department of Parks and Recreation.

Poison oak doesn’t only prey on the young and the careless. Austin, who works at the U.S. Forest Service’s Ojai office, recently had to get a cortisone shot “for a really bad case,” she said. “And I knew what poison oak looks like.”

What makes the plant even more insidious is that it is potent even without leaves. The berries and stems are also slathered with a sticky sap containing urushiol, an irritant. Falling berries or blowing leaves can spread urushiol on rocks and logs, and people who sit on these objects usually wonder how they contracted poison oak on the backs of their thighs.

Once urushiol makes contact with skin, it penetrates in minutes but no rash develops for another 12 to 48 hours, giving the victim a false sense of security. But if poison oak hasn’t erupted even weeks after a visit to the forest, it’s still no guarantee that it won’t. Urushiol can remain on clothing for up to a year--the old hiking vest hanging in the closet could be a time bomb unless it is washed thoroughly, experts say.

The family dog also needs to be bathed after a romp in the woods, not so much for its well-being--animals can roll around in the plant without breaking out--but to prevent its owner from petting urushiol-matted fur.

Campers should be aware that burning poison oak can be dangerous, experts say, because urushiol vapors can damage lungs.

Experts also debunk the belief that people build immunity with frequent exposure. Just the opposite is true. “Your allergic reaction increases the more you’re exposed,” Goode said.

Just because you’ve never gotten poison oak symptoms doesn’t mean you never will. Rose Rumball-Petre, a resource-management specialist with the National Park Service, thought she was immune after 29 years without so much as an itch, but six months ago she suffered an outbreak.

Although cortisone is used for severe cases, over-the-counter remedies are also effective. Washing with Teknu after exposure will either prevent or minimize outbreaks, experts say, and the application of a barrier cream named Stockogard eight hours before a hike will keep urushiol from penetrating the skin.

Homeopathic remedies are also available. Ron Webster, a Santa Monica trail builder, uses what he calls the “Chumash method” for poison-oak prevention: He eats the leaves. Although medical experts give credence to Webster’s theory that ingesting small doses can create a tolerance, they don’t recommend it.

“The medical community still isn’t sure if the oil absorbed by the lining of the stomach can actually induce antibodies,” Rehder said.

Despite the onslaught of poison oak this spring, there won’t be any war on the plant. State and federal agencies responsible for local forests will clear the plant from trails but won’t launch a zero-tolerance campaign of spraying with herbicide or chopping it down.

“Eradicating the plant would be an impossible task,” Austin said. “Poison oak is such a strong plant, you can’t really cut it back. Plus, it’s a native species.”

And not everyone wants to see poison oak wiped out. Jo Kitz, past president of the Santa Monica Mountains Native Plant Society, says the plant has been a part of the local ecosystem for hundreds of thousands of years, and people should learn to live with it.

“I don’t think we should go on a vendetta just because it gives us a rash,” she said. “I don’t think something that grows naturally is wrong.”

FYI: What to do when a poison-oak rash breaks out? Dermatologists recommend using a topical over-the-counter medication such as Calamine lotion or a prescription salve such as Lidex. Avoid scratching. Contrary to popular belief, scratching won’t spread the rash but may break the skin and cause infection. Severe cases of poison oak may require antihistamines or cortisone shots.