He Has an Itch to Overcome Poison Oak : Deodorant Ingredient Helps, Doctor Finds

Times Staff Writer

Dr. William Epstein has devoted 30 years--half of his life--to finding a way to protect humans from poison oak. Finally, Epstein and his fellow crusaders against the weed seem to have come up with a solution: mud.

A professor of dermatology at the UC San Francisco School of Medicine, Epstein admits he once scoffed at the suggestion that a substance might be found that would effectively block urushiol, the toxic ingredient in poison oak, poison ivy and poison sumac.

Tested, Despite Doubts

He supposed that any sort of topical barrier would be likely to wear off in conditions encountered by hunters, hikers and outdoor workers.


Despite his skepticism, Epstein ran tests on organic clay filler, an ingredient in antiperspirants, which is known to bind with urushiol, thus rendering the toxin inactive.

“We got a can of deodorant off the shelf and sure enough, it seemed to work,” Epstein said in a telephone interview.

Epstein ordered a sample of the activated clay filler from its manufacturer, United Catalyst of Louisville, Ky.

“It came in a jar, and it looked like mud,” Epstein said. He asked the company to supply him the material in aerosol form. It still looked like mud, Epstein said, but it disappeared when rubbed into the skin. More importantly, the clay worked to block poison oak for up to 24 hours, even when exposed to water.

May Be in Stores Soon

Epstein said the substance, called Ivy Block, should be commercially available in about a year.

Until now, regular oral doses of an antigen had been the only recourse for people attempting to stave off poison oak dermatitis. This method is unpopular because it causes itching.

People who knew they had come in contact with the toxic plants could rush to a water source and rinse skin and clothing. This is sometimes effective in preventing a rash, as long as it is done soon after exposure to the plant, Epstein said. Once afflicted, victims have resorted to topical steroids and salves, which sometimes provide partial relief.


At least half the U.S. population is somewhat sensitive to urushiol, with about 30 million people acutely sensitive, Epstein said.

Especially vulnerable are firefighters who must hack their way through fields of poison oak.

Jerry Oltman of the U.S. Forest Service Equipment Development Center in Missoula, Mont., said that even a minor reaction to poison oak can cause itching that interferes with sleep, a significant problem when firefighters have to be back on the line the next day.

“It’s not easy to sleep in a forest camp anyway,” he said.


Those who have suffered severe reactions to the weed learn to recoil from the plant the same way they would a rattlesnake in the brush, Oltman said.

“Some firefighters who are very sensitive have just given up being firefighters.”

The Forest Service reports that on any major forest fire, 30% of their ranks must leave the line or even be hospitalized due to reactions to poison oak and ivy. Epstein has collaborated with the U.S. Forest Service for seven years in an effort to reduce the toll.

Last year, samples of Ivy Block were shipped to 60 Forest Service employees who had been selected for their sensitivity to poison oak. The users reported good results, with no side effects. Oltman is distributing Ivy Block to forest crews around the nation this summer. Among the users are the “hot shot” crew, a 20-person specialized hand crew that is the first line of attack on fires in the Mt. Baldy district of the Angeles National Forest.


Oltman said he expects that Ivy Block will soon be in the glove compartment of every forest worker’s pickup truck--just like the ever-present can of insect repellent.

“There’s nothing like it,” he said.

Epstein seems almost embarrassed by the attention the spray is getting. He likens Ivy Block to Scotchguard for water-proofing--it works well enough if you don’t fall into a lake. Similarly, an application of Ivy Block might decrease the odds of getting a rash, but it will not allow you to frolic in a field of poison oak.

Epstein is applying for funding to develop a “tolerizer,” a substance that would work on the immune system to block reaction in the skin.


In his efforts to solve the poison oak problem, Epstein suffers an occasional bout of itching himself. The last time, he recalled, was when he was injecting soldiers at Ft. Ord with antigen at the rate of 150 men an hour. He realized the syringes were leaking and he was sitting in a puddle of poison oak.