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Defending Yourself Against Poison Ivy

07/19/2002
by Silent Doug

Enjoying the great outdoors brings with it many hazards that aren't unique to letterboxing. One of the most common annoyances is poison ivy (and its cousins, poison oak and poison sumac). Poison ivy can be found throughout the Midwest and the East, making it quite common in the U.S.

Poison Ivy on the ground
Poison ivy (Rhus radicans) as ground cover. Note the variations in color, shape and size of the leaflets. (Photograph Copyright © 2002 Silent Doug.

Coming into contact with one of these plants will cause an allergic reaction in approximately 85 percent of the population, according to the American Academy of Dermatology. And, as anyone who's been exposed to poison ivy knows, the result of contact is a skin rash that itches like crazy!

The cause of this reaction is a chemical in poison ivy's sap called urushiol (pronounced oo-roo-shee-ohl). Technically speaking, this sap is only found inside a poison ivy plant, in the roots, stems, bark, leaflets and certain parts of the flowers, so merely brushing up against a leaf would not cause a reaction. However, poison ivy is very delicate, so its stems and leaves are easily broken or torn by the wind, animals, human footsteps or even bugs who eat holes in the leaves. The reality is that contact with the plant practically guarantees that you'll be exposed to urushiol.

As a result, the best way to protect yourself from poison ivy is to avoid the plant altogether. But the old adage, "leaves of three, let it be; berries white, take flight," only begins to describe the plant. Poison ivy has a compound leaf consisting of three leaflets on a stem. Poison ivy leaves are fat at the base, coming to a point at the end, and each leaf typically has one to three notches on each side. However, leaves can also have no notches at all. The leaves may be glossy or dull, and their color will range from bright red in spring (or whenever they start growing), to green (both light and dark) in summer, to a mottled red, yellow and/or orange in the fall. Leaves can be as small as one half-inch in length, or six inches long.

Poison Ivy vine on a tree
Poison ivy vine climbing a tree. (Photograph Copyright © 2002 Silent Doug.)

As if this weren't enough, poison ivy can grow as ground cover (in reality, a trailing shrub running along the ground), a creeping woody vine (such as on a tree or fence post) or even as an erect woody bush. The ropelike vine is noticeably fuzzy, which are actually aerial roots along the stem. To further complicate identification, the plant sometimes grows with four to nine leaflets on a stem, not just three. In June or July, the plant sprouts yellowish-green flowers in compact clusters. The plant also produces a waxy, berry-like fruit in large clusters.

Poison ivy doesn't like too much sunlight, so you won't find it in the middle of a field. It doesn't like too much shade, so you won't find it deep in the woods. But along fence rows, or at the edge of a forest, or alongside a trail, you'll usually find poison ivy growing.

Urushiol doesn't just can stick to your skin. It can also stick to clothes and shoes and packs, and remain there for years -- and give you a case of poison ivy the next time you put on that jacket or lace up those boots. Laundering clothes in regular detergent or wiping surfaces with isopropyl (rubbing) alcohol will eliminate the uroshiol.

Animals aren't sensitive to urushiol, however your dog's coat could pick up the chemical and later pass it along to you. The skin on your palms is usually too thick for uroshiol to penetrate to cause a reaction, but you could pass along the toxin to the next item or person you touch.

A relatively new product manufactured by EnviroDerm Pharmaceuticals is Ivy-Block, available at drug stores. If applied before you come into contact with the plant, the lotion can prevent you from a poison ivy, oak and sumac rash. The product won't work on your clothes, so you must still take precautions to avoid the plant.

Poison Ivy on a tree
No, these aren't leaves on a tree -- this is poison ivy on a tree by the side of the trail. (Photograph Copyright © 2002 Silent Doug.)
Once you've come into contact with poison ivy, you can expect swelling and blisters (as well as itching) to appear in 12 to 48 hours. If you suspect that you've been in contact with the plant, you can immediately clean the affected area with isopropyl alcohol and get rid of the urushiol. But don't go back into the woods on the same day, since the alcohol removes your skin's natural protective oils and makes it twice as easy for uroshiol to penetrate. And don't wipe off your skin with alcohol while still wearing the clothes you wore while in the presence of the poison ivy plant. Later, when you undress, the urushiol that's still on your clothes is liable to be transmitted to your skin.

You can also rinse well with water at any temperature, but avoid soap unless you have warm water. In cold water, the soap will only pick up the uroshiol and move it around on your skin. As soon as possible, take a warm (not hot), soapy shower. If you take a bath, be sure to rinse the tub thoroughly when you're through, since urushiol might stick to the side of the tub.

Once you've got a full-blown rash, the only real treatment is to apply a topical cream to the affected area. Calamine is the most common lotion used to treat poison ivy, and it helps dry the rash's blisters while soothing the itch. I like Band-Aid Fast Relief Calamine Spray, which includes some benzocaine in its formula to quickly relieve the itchy rash, and since it's a spray, you won't need to rub lotion onto your skin. (Contrary to popular belief, you can't spread poison ivy by scratching the blisters, however.) The rash, blisters and itch normally disappear within 14 to 20 days.

For more information on poison ivy, a great resource is Jon Sachs's Poison Ivy Site.

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