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August 1, 1999
Unruly Urushiol
Poison Ivy Facts and Fictions
by Rebecca Chastenet de Géry

As an enthusiastic Girl Scout, I fearlessly tramped through patches of poison ivy and proudly emerged unscathed. I believed, erroneously, that I was immune to the stuff, so the year my "immunity" wore off, it came as a miserable surprise. I still don't know if I got poison ivy by burning debris that unbeknownst to me contained it, or by drying myself off with a towel that had covered a well-camouflaged patch. But however it came to me, it did so with a vengeance that made up for all those rash-free summers. My reaction was full blown. Row after tiny row of itchy, red spots covered me from head to toe and even crept into my ears, mouth and genitalia. Within a day, I looked like some sort of swollen, seeping monster, and relief was found only in occasional baths of Epsom salts. A cortisone shot eventually provided some relief, but today I never, ever venture near the evil "leaves of three" if I can, indeed, "let them be!"

After sorting out poison ivy fact from fiction, I've come to discover my experience wasn't exceptional. Each year outdoorsy types across the country wind up with a topical rash of varying severity-the result of a brush with the abundant plant. The real culprit is the plant's sap, a toxic oil known as urushiol, that is found in all parts of the plant: in its leaves, stems, roots, flowers, and berries. Gently bruising poison ivy is all it takes to release this vicious sap, which means that a child's ball, the swipe of a pant leg, or even the passage of a furry animal is enough to make poison ivy poisonous. What's worse, urushiol is exceptionally hardy stuff. Contrary to popular belief, poison ivy doesn't "hibernate" in the winter. And you could get it simply by removing tainted clothing, petting Rover, or manhandling garden tools or sports equipment that have come into contact with the plant. An internal allergic reaction might occur if poison ivy is burned and the resin is breathed into the lungs. And those who prefer the Great Outdoors to indoor plumbing beware: Using a urushiol tainted leaf as toilet paper could prove positively horrifying.

It turns out no one is immune to urushiol, 70-80% of Americans are mildly to moderately sensitive to the allergen with about 10-15% at the end of each spectrum. But the good news is that the dermatitis it produces is a self-limiting condition, meaning it will disappear on its own within 2 weeks in most instances. Additional good news is that the poison ivy rash doesn't "spread" via the rash's blister fluid. Only those body parts that come into contact with the sap will blister, although the rash may appear progressively as a result of urushiol's varied rate of absorption into the skin. If you think you might have been exposed to poison ivy, wash your skin thoroughly with soap and water and wash your clothes right away. Rubbing alcohol is even more effective in removing the oily resin from the skin. For relief of the discomfort caused by poison ivy, dermatologists recommend the following:

  • Cool compresses
  • Soaks with colloidal oatmeal
  • Calamine lotion (Look for brands without topical antihistamines, which can cause sensitivity.)

Those suffering from serious cases of poison ivy should contact their physician who may choose to administer a corticosteriod treatment.

Quick Reference: Poison Ivy Facts

  • Poison ivy, poison oak, and poison sumac all contain the allergen urushiol.
  • All parts of the poison ivy plant release urushiol.
  • Poison ivy lives year-round in moderate climates. It does not "hibernate" in winter.
  • A person doesn't necessarily have to touch the plant to get it. The resin adheres to clothes, animal hair and other objects and can be transferred to the skin from an intermediary source.
  • Outbreaks can occur within 8 hours of exposure, but also can occur up to two weeks after exposure if the resin remains on the skin for a prolonged period of time.
  • If contact with poison ivy is suspected, the exposed area of skin should be thoroughly washed with soap and water as soon as possible.
  • The ability for the resin to remain on the skin (even after washing) can cause a later eruption.
  • Exposed clothing or pets should also be washed immediately.
  • Rubbing alcohol can be even more effective in dispersing poison ivy's oily resin.
  • Poison ivy cannot be spread by the rash itself or fluid from the blisters that form on the skin.
  • Water does not spread poison ivy to other parts of the body or to other people.
  • The best defense is to keep away from the plant entirely, but a non-prescription lotion called bentoquatum (IvyBlock) may be applied to as a barrier to potential exposure. The lotion is applied directly to the skin where it dries to form a white protective coating.