Blocking The Big Itch

Rub on a preventive "shield" and poison ivy won't get under your skin.

By Buck Tilton, BACKPACKER Contributing Editor, April 1998

Finally, a sure-fire way to avoid getting poison ivy. Think about it: No more rash, no more oozing blisters, no more itch that can turn even the most placid and subdued person into a crazed, teeth-gnashing fiend who'll sell soul and future for a few moments relief. And it was right under your nose all the time: Move to Antarctica.

There you go. Of course, you may be allergic to penguins but life's not perfect. If it was, there would be none of this dreaded plant life lurking along trails, just waiting for a hapless hiker to wander by, brush against the leaves, then spend the next week or two scratching like a flea-infested hound. And despite the legions of backwoods lovers whose mantra is "Leaves of three, let it be," many still somehow manage to encounter poison ivy and are forced to try and cope with its dreadful side effects.

There's a light at the end of the ivy-covered tunnel, however, because medical science has been hard at work developing ways to keep the itch at bay. Prevention, after all, is far better than trying to claw the skin off your bones.

THE ROOT OF THE PROBLEM

The poisonous weeds in question grow in all Lower 48 states (Alaska and Hawaii are safe), and take the form of either a small shrub or a woody, ivy-like vine. East of the Rocky Mountains you'll find poison ivy, in the West it's poison oak, and in wet areas of the Southeast poison sumac. The name isn't as important as what's lurking in and on all three: urushiol, a usually colorless (sometimes light yellow) oil that's quite potent. Two to 2.5 millionths of a gram can trigger a reaction in highly sensitive people, which is about 50 percent of adults in the United States. Another 35 percent react to larger concentrations of urushiol. Sensitivity to the oil is the single most common cause of allergic skin reaction in the United States, and the leading cause of worker's compensation payments related to outdoor injuries.

When urushiol soaks into human skin an allergic reaction takes place. Not everyone reacts the same, but most people first develop redness where they contacted the oil, usually in the form of streaks where the plant brushed against the skin. It takes varying amounts of time for the reaction to show up. On thick-skin areas of your body, such as palms and the bottoms of feet, the oil soaks in more slowly than on thin-skin areas like arms and legs. If you're highly sensitive, you'll see the dreadful signs in 2 to 6 hours. Those who are less sensitive may not show symptoms for days, or in some cases, for up to two weeks. For most people, though, 12 to 48 hours is all it takes to know whether the next 10 to 14 days will be cursed (and have you cursing). Adding insult to injury is the fact that places on your body previously affected by the rash can fire up once again, even if urushiol contacts a distinctly different part of your anatomy.

There may be some swelling. Blisters eventually erupt and discharge fluid, which crusts over in the final stage of this very unpleasant chain of events. And as for the Big Question: No, the blister fluid doesn't cause the rash to spread. What usually happens is the urushiol gets on your hands, you touch yourself, and that's how the rash shows up in all those odd places that never see daylight, much less come in contact with plants.

The best plan of attack is avoidance, but with urushiol, it's what you can't see that can drive you mad. For instance, even if you're wearing long pants and sleeves you can get a rash on your body because the oil can get on your clothing and boots. You get home, remove your footwear, the oil gets on your hands and voila! (Urushiol stays active for years, by the way.) Then there's the sad tale of a savvy fellow I know who can spot poison ivy in the neighboring county. While wearing shorts on a recent hike he stopped for a rest break, surveyed the area for dangerous plants, and saw none. He confidently rested against a tree the wind recently toppled. Three days later, when the backs of his legs were aflame with the rash and massive blisters, he realized that once upon a time, poison ivy vines had thrived on the tree's bark, leaving behind-you guessed it-lots of urushiol.

The moral: Avoidance is a fine idea but if you're highly sensitive, you can't take chances. You need to lower your risk factor, and here's where science comes in. For years researchers have been trying to develop a "barrier" cream that when applied to skin, will block or at least hinder absorption of the irritating substance. No luck, until 1995 when the Journal of the American Academy of Dermatology (Volume 33, Number 2) reported on a successful barrier cream study. A lotion made of an organic clay mixture was smeared on one forearm of 211 healthy and extremely brave men and women who were sensitive to poison ivy. One hour later urushiol patches were taped to both forearms and left in place for four hours. After the patches were removed, both arms were washed with liquid detergent and water. The results: 68 percent who had reactions on unprotected forearms suffered no reaction on protected arms. Those who did have a reaction on their lotion forearms had significantly less irritation compared to the unprotected arm.

In 1996 the proven formula, dubbed Ivy Block Lotion, was introduced to the market. For almost two years it was the only barrier-type agent available that had the U.S. Food and Drug Administration seal of approval. This past spring a new FDA-sanctioned player called Work Shield emerged. Being the curious type, I got samples of both, and here's what I learned.

Ivy Block: The instructions say to apply to the skin 15 minutes before treading where poisonous plants live. I coated one arm with the stuff, and found it to be virtually invisible with a mild but not unpleasant odor. Since it's supposed to form a "barrier," I wasn't surprised that my treated arm remained slightly creamy to the touch. The manufacturer recommends reapplication every 4 hours during times of exposure. If you sweat heavily, you should be okay because there's a bonding agent that's supposed to help the lotion stay put. Wash off with soap and water after the danger has passed. A 4-ounce bottle costs around $12 and can be purchased at most drug stores or larger supermarkets. Contact: EnviroDerm Pharmaceuticals, Inc., P.O. Box 32370, Louisville, KY 40232-2370; (502) 634-7700.

Note: In May Avon Skin-So-Soft Ivy Block Lotion was unveiled. According to an Avon spokesperson, it's simply Ivy Block marketed through the Skin-So-Soft line of products. The reason: "to reach more families." Price is the same. Available directly from Avon (800-367-2866 or http://www.avon.

com), or through a sales representative in your neighborhood.

Work Shield: The manufacturer says one application will provide about 8 hours of protection. Work Shield quickly dried on my skin to a greaseless, odorless, slightly creamy film. As a bonus, it's FDA-registered not only as a barrier cream, but also as a treatment to help stop the itch and dry up weeping blisters. Like Ivy Block, it should be washed off after the threat has passed. A 4-ounce bottle costs around $12. Contact: Dermaron Corp., P.O. Box 3012, Peabody, MA 01961; (888) 489-6625.

Now for the question I know you're dying to ask: Will they prevent the torturous itch? To find out I stripped naked, smeared myself with each, vigorously rolled in poison oak for 20 minutes, then...just kidding. Actually, my curiosity only goes so far. But since both are FDA approved, that means the feds are satisfied that each stands up to the stated claims.

NIP IT IN THE BUD

Besides using a barrier cream, there are other lines of defense in the itch wars. Of prime importance is washing as soon as you realize you've touched a poisonous plant. Lightning fast reflexes aren't required, since even the extremely sensitive have 5 to 10 minutes before urushiol soaks in enough to cause trouble. Those of lesser sensitivity may have up to 2 hours. Use cold water and lots of it; avoid hot water because it softens and spreads the oil, and opens skin pores.

As for soap, no need to use it if you act within the first 3 minutes of contact. Many dermatologists, however, do recommend washing with some type of cleansing agent or detergent if more than a few minutes have passed. If you're highly sensitive, repeated washings aren't a bad idea.

Organic solvents like alcohol and gasoline, while usually not readily available in the wilderness, work even better than soap and water. Lacking those, you can use stove fuel. Repeatedly dab the exposed area with pieces of solvent-soaked cotton, and then rub with fresh solvent-soaked cotton. Don't leave the gasoline on your skin but for a few seconds, and avoid using the same piece of cotton for more than a few swipes or you may redeposit urushiol on your skin. The National Safety Council, being a cautious bunch, says you should conclude by washing five to six times with soap and water, then rinse with rubbing alcohol, followed by clear water.

You may notice commercial products on drug store and outfitter shelves that claim to wash off urushiol, and often, the accompanying itch. Before buying, check the label and see if the product is FDA approved. If not, you decide whether it's worth the gamble. Most are little more than a soap-based liquid anyway, and some even tell you to scrub the rash with their product. I've never done this, but I talked to a few folks who have and they told me the obvious: rub and scrub itchy skin and it'll itch even more.

Be sure to clean under fingernails where urushiol may lurk. You can also pick up the oil from your clothing, the bottom of your tent, your hiking staff, even the hair of your dog or cat. If you've been in poison plant country, give Fido and your clothes and gear a good washing once at home.

RASH RELIEF

Sometimes, despite your best preventive measures, you learn about a poisonous plant encounter after it's too late. Although nothing will cure the rash, you can try to relieve the itch.

First a note about what probably won't work. Avoid topical lotions, creams, or sprays that contain antihistamines or anesthetics, since the additives have a tendency to make things worse. Most topical corticosteroids sold over the counter are too weak to do much good. Aspirin, nonsteroidal anti-inflammatory drugs (such as ibuprofen), and oral antihistamines have little or no effect, although an antihistamine might help you sleep.

Your physician can prescribe a strong topical steroid that may help if you start using it before the rash turns into blisters. As for homeopathic treatments, there are over 100 different folk remedies involving substances provided by Mother Nature, but all are scientifically unproven and most seem to have little effect. There are two plants, however, that many urushiol intolerant folks swear by. Plantain, a.k.a. buckhorn, has leaves that release a pale green sap when crushed. When dabbed on the rash, the sap reportedly stops the itch for 24 to 48 hours.

Jewelweed has as many supporters as plantain. The sap from crushed plants can be applied to the rash, and some claim relief after soaking in bath water mixed with the juice of approximately one pound of plants.

Other home treatment options I've heard folks swear by:

Topical applications of plain old calamine lotion.

Soaking in a tepid bath with one cup Aveeno brand oatmeal or two cups of linnet starch added.

A cold, wet compress placed on the rash area. Some sufferers get relief by standing in a hot shower for several minutes, then gently patting the water off the itchy areas.

If a close encounter with urushiol causes you to feel ill, there's significant swelling, or the rash is in a particularly sensitive area, forgo any attempts at self treatment and high-tail it to a doctor for medical attention.