Dermatologists estimate that about 15% of the population has no allergic reaction to urushiol, the toxic oil or resin found in poison ivy, poison oak, and poison sumac. For the rest of us, however, a brush with these woody shrubs or vines can have miserable consequences, including blisters, swelling of the skin, and an itchy rash that can last up to three weeks. Since these plants are quite common in North America—poison ivy and sumac are widespread in much of the eastern and central U.S. as well as parts of Canada, and poison oak is prevalent in California and other parts of the western U.S.--you're likely to encounter them sometime. Here’s how to avoid getting too close.


Steps

1. Learn to identify poison ivy, poison oak, and poison sumac, and when you see them, avoid them at all costs. All are woody vines or shrubs that grow independently or climb and trail up trees, fences, and other objects, and along the ground.
   • A cluster of poison ivy. Note the arrangement of three leaflets per leaf. Also notice the variety of appearances the leaves have. Poison ivy has thin, often shiny, bright-green compound leaves (in the fall the leaves turn red, and young leaves may be orange) each with three leaflets (each leaf is on a separate stem, and the leaflets meet at the end of the stem): hence the saying, "leaves of three, leave it be." When poison ivy is in its vine form, and has grown very large, the main stem can appear hairy, hence the saying, "hairy rope, don't be a dope." Depending on the time of year, the plant may have clusters of small, yellowish-green flowers (usually in June) or hard, greenish-white berries. The stem is woody and in its native territory is the only native vine with aerial roots (which should not be confused with the exotic invasive English Ivy's tendrils) except in young plants, and is often reddish.
   • Poison oak with leaves in green phase. Notice the "leaves of three." Poison oak grows primarily in dry areas and also has leaves of three leaflets, and while the leaves often resemble "true oak" leaves, they may take on other appearances as well. They are usually green in spring and summer, turning reddish in late summer and fall. The flowers and berries are white to yellowish-green, as in poison ivy (hence another saying, "berries white, poisonous sight").
   • Poison sumac leaves. Poison sumac has leaves of 7-13 leaflets, produces a small, white or grey berry, and is found in boggy or riparian areas. Hereafter, the article refers only to poison ivy for brevity, but the steps for poison oak and poison sumac are the same.
2. Poison oak with leaves in red phase Wear long pants, long-sleeve shirts, socks, and fully-enclosed footwear when walking in poison-ivy infested areas. Not only will covering your skin help protect you from poison ivy, but mosquitoes won't bother you as much either.
3. Wear gloves when working where poison ivy may be present, such as when cutting down trees in the woods, mowing brush, etc. It is recommended that you wear plastic gloves over cotton gloves because urushiol (the oil in poison ivy that is responsible for the allergic reaction) can eventually soak through cotton gloves. Not only is getting poison ivy on your hands a pain, it makes it very easy to spread to the rest of your body, so gloves are an important defense.
4. Apply a barrier cream, such as Ivy Block or Stokoguard, if you know you have a good chance of exposure to poison ivy. While no vaccine or medicine has been shown to prevent reactions to poison ivy, barrier creams containing bentoquatam seem to be effective in slowing the absorption of urushiol into the skin. Apply the cream as directed, usually about an hour before potential exposure, and thoroughly wash it off within four hours, reapplying as necessary.
5. Exercise caution not to touch your face or eyes (or other exposed skin) with hands or gloves that may have come in contact with poison ivy.
6. Watch out for poison ivy oil carried back on pets. Even if you avoid poison ivy, your pets may not, particularly if you let them run free in the woods or in a large yard. The urushiol sticks to pets’ fur but typically does not irritate them, so you won’t be able to tell if they’ve gotten into it. Keep dogs on a leash and keep a watchful eye on all pets or farm animals when in poison ivy country. If you think there’s a chance your pet may have been exposed, thoroughly wash it with a good pet shampoo. Wear plastic gloves, cover exposed skin with clothing, and wear safety goggles. Try to prevent your pet from shaking off on the first wash (this is harder than it sounds; hence the safety goggles). Wash and thoroughly rinse your pet with the shampoo and warm water three times in succession to make sure the urushiol is gone. Towel dry, and immediately launder the towel in the washing machine. Let your pet fully dry before touching it with bare skin.
7. Be careful around streams or ponds. If the plants are hanging into the water the oils can spread and you may be exposed without ever having seen the plant. This can be particularly serious if you swim or bathe in contaminated water
8. Beware latent resin. Urushiol resin can remain active for a long time—years if kept dry, so handle potentially-exposed objects with care. People commonly end up with a reaction from touching garden tools that have been left in the yard, fences from which poison ivy has recently been removed, and clothes that were exposed to urushiol but were put away before the wearer came in contact with the oil. Thoroughly wash or dispose of clothes, tools, or other objects which may have come into contact with poison ivy, and use the same caution touching dead poison ivy plants or plant parts as you would if they were alive. To wash objects, use hot, soapy water and let the clothing or object dry outside for several days.
9. Control poison ivy manually or with an herbicide containing glyphosate. Spraying poison ivy with products such as Roundup or Ortho Poison Ivy Killer will kill the plants and reduce your risk of exposure in yards, gardens, and parks. Keep in mind, however, that such products will usually kill other nearby plants, as well. If you wish to remove poison ivy by hand, make sure to dress appropriately, wear barrier cream, and follow all other necessary precautions. Manual removal can be tedious, because you must remove all parts of the plant—stems, leaves, and roots—or it may regrow.
10. Dispose of poison ivy or exposed objects properly. Check with your municipality to find out any local regulations on poison ivy disposal. In general, dispose of poison ivy or contaminated objects in plastic garbage bags, and mark the bags to warn your garbage handlers. You may also bury the poison ivy remnants, but be sure to bury them deep enough (at least 12 inches to be safe) to prevent regrowth.
11. Wash exposed skin immediately. It takes about 10-30 minutes after contact for urushiol to bind with skin, so fast cleaning may prevent a reaction. If you think your skin may have been exposed to poison ivy, clean the affected area with rubbing alcohol, and then wash it with cool water. Do this while outside, if possible, and when you are finished proceed immediately to take a hot shower using plenty of soap. Scrub under fingernails thoroughly to wash off any remaining resin.

Tips

• If you need help remember what is poison ivy and what is not, just remember this rhyme: "Leaves of three let it be; if it's hairy, it's a berry!"
• Use Tecnu Extreme or Zanfel cleanser if you know you have been exposed to poison ivy. They are both very effective at removing the urushiol--which is vital. Even if used at the first sign of itching or rash they can reduce the effect and severity of the allergic reaction.
• While leaves of three leaflets are by far the most common arrangement, poison ivy leaves will occasionally display more or fewer leaflets.
• Poison ivy, poison oak, and poison sumac cannot be identified by their size. Young plants are obviously quite small, while larger ones can grow up trees 5 or 10 feet. The overall appearance of the plants can also be deceiving: they can appear either as a vine or as a shrub. Several woodland plants can be mistaken for poison ivy, poison oak, or poison sumac but when in doubt, avoid contact with a plant.
• A poison ivy reaction usually takes a day or two to appear, although it could take as little as a few hours or as much as 7-10 days. If you think you’ve been exposed to the plant, the sooner you wash your skin the better your chance of having little or no reaction.
• While some people experience a reaction to poison ivy the first time they have contact with it, it commonly requires several exposures to the plant before someone develops adverse effects. Thus, don’t assume that you are immune to poison ivy just because you’ve never had problems with it before.
• If there are trails wherever you happen to be going, stay on them. Normally, poison ivy has been cleared out from these areas, but of course there are no guarantees.
• Poison ivy can be an integral part of the natural environment, and deer and other animals eat or live in poison ivy. For these reasons, consider peacefully coexisting with poison ivy if you have it on your property.
• Vinegar is another cleansing agent you might try after exposure to poison ivy (urushiol).
• If you are camping or otherwise unable to treat poison ivy with soap and water or various over the counter medications but you know you've been exposed consult your field guide for a plant known as Jewel Weed. Jewel Weed prefers moist, aluvial areas and the juice from the broken stem of the plant is a folk remedy for poison ivy exposure. This, like most folk remedies, should be taken with a grain of salt and you should still seek proper treatment.
• If you touch poison ivy put deoderant stick on it right away if you arent near water. This will prevent the oil from spreading anywhere else.
• If you don't have any other soap available, trying washing off with dish soap (just as it cuts the grease off your dishes it effectively cuts the urushiol oil off the skin).
• During river paddling trips in the east, especially in the piedmont and coastal plain, poison ivy often covers large areas along the shoreline. If you need to get to shore, beat down a path through the poison ivy, then immediately return to the river and scrub off using river silt and rinse off in the river.
• If you have irritation due to exposure to one of these use listerine on the bad areas -- it dries it out immediately.

Warnings

• Sometimes poison ivy reactions can get very serious. If you have never had poison ivy before, and you get it, it can be much worse than normal. Contact your physician or call 911 if you experience extreme symptoms.
• Never burn poison ivy. Burning can cause the oil to get into the air, and you can then breathe it in or get it in your eyes. The smoke from burning poison ivy will cause the same reaction in your lungs that normally happens on the skin. Reactions to this kind of exposure can be far more serious than those resulting from topical contact, in fact breathing the smoke from burning poison ivy can cause death.
• Follow the manufacturer’s directions and heed product warnings when using any herbicide. These products may be harmful to humans and pets, as well as to garden plants.
• It's important to first wash with rubbing alcohol or vinegar or at least rinse off with cool water before taking a hot shower with soap. Hot water opens pores and can speed the urushiol's entry into the skin. Rather than dissipating the oil, soap will only spread it around. Don't reenter poison ivy after you've washed with rubbing alcohol, however, as the alcohol dries your skin and removes its protective oils.
• Mango is a close relative of Poison Ivy and contains trace amounts of urushiol. If you exhibit a very strong reaction to poison ivy you should also be careful when around mango trees or handling mangoes.