Each year, the first warm weekend of spring inspires millions of hikers, campers, and other outdoor enthusiasts to hit the trails. Come Monday morning, a few of them will wake up scratching. By Tuesday, these unlucky souls may have full-blown poison ivy - the red, itchy rash that will send them searching for calamine lotion or other remedies. According to the National Institute of Allergy and Infectious Diseases, about 85% of Americans are allergic to poison ivy and its close relatives, poison oak and poison sumac.

Where’s the “poison”?

Only direct contact with urushiol - a toxic plant oil that protects the leaves, stems, and even roots of these “poisonous” plants - can cause an allergic reaction. But like a clump of poison oak hidden in a bed of innocent-looking ferns, urushiol can be sneaky. It can rub off on your skin, hair, clothing, outdoor gear, even your pets. Urushiol can also collect under your fingernails if you scratch exposed skin before you’ve washed the oil off. Once this happens, continuing to scratch can help spread the oil, which spreads the rash. And keep an eye out when collecting wood for a campfire. Burning poisonous plants - roots, stems, or leaves - can send urushiol particles into the air. Breathing the smoke can irritate your eyes, nose, and throat.

To prevent urushiol from causing a reaction, make sure no oil lingers on any material that may come in contact with your skin - now or in the future. The toxic ingredient in urushiol can remain active for up to one year. If you suspect you’ve had a run-in with a poisonous plant, take these steps to help prevent a reaction:

• Shower and shampoo in cool water. Hot water opens pores, making it easier for urushiol to penetrate your skin. You can also try cleaning the affected areas with rubbing alcohol before hitting the camp shower - but only if you’re washing off at the end of the day. While alcohol effectively removes urushiol from your skin, it also strips away your skin’s protective oils, leaving it more vulnerable to a second encounter with poisonous plants.
• Clean under your nails. Use a small brush or extra toothbrush for a thorough cleaning job. Remove the dirt and oil, and wash with soapy water. Don’t forget to wash the brush and any other items - including towels - you use before the oil has been removed.
• Wash the clothes you wore immediately, in a separate load of laundry, rather than letting them languish in the hamper.
• Leave your shoes outside to avoid tracking urushiol into the house. Clean all your outdoor gear with soap and water.
• Bathe your pets if they have been exposed to poisonous plants. Otherwise, patting your dog on the head could mean a case of poison ivy for you.

Even after direct skin contact with urushiol, you still have hope. It takes 10 to 15 minutes for the oil to penetrate your skin. You may be able to avoid an allergic reaction by removing the oil with soap and water before your skin has absorbed it.

Beating the itch

Unless you notice that the plants brushing your knees are poisonous, you may not realize until later that you’ve been exposed. It can take anywhere from 6 to 48 hours after exposure for symptoms to appear: redness and irritation, followed by itchy bumps and blisters. These symptoms may persist for up to two weeks. If you have a severe rash, your doctor may prescribe antihistamines or an oral steroid, like prednisone. For less severe reactions, try an over-the-counter antihistamine to reduce the itching and swelling. Cortisone creams, ointments, and sprays also work well.

Drugstores and health markets are filled with natural remedies for an itchy encounter with a poisonous plant. Calamine lotion or aloe vera gel can help soothe the itching and discomfort of the rash. A wet, cold compress of Burow’s solution (diluted liquid aluminum acetate) is another soothing option, available over the counter in most drugstores. For full-body treatment, try a cool shower or a warm bath with baking soda or an oatmeal bath preparation.

You can’t always steer clear of poisonous plants along the trail. But you can outfit yourself in a long-sleeved shirt and long pants - even gloves. Protective clothing offers the best defense, preventing urushiol from touching your skin. Barrier creams can also help ward off reactions to poisonous plants. When applied at least 15 minutes before contact, a barrier cream can keep urushiol from penetrating your skin, even if you come in direct contact with a poisonous plant.

Prevention is the best medicine

The best way to prevent an allergic reaction is to avoid poisonous plants altogether. Check a local field guide to identify the plants in your area. While the appearance of poison ivy, oak, and sumac may vary from region to region, certain species share common characteristics. Remember the rhyme, “Leaves of three, let them be.” Many poisonous plants have three leaves attached to a single stalk. Throughout the spring and summer, their leaves may appear dark green and shiny. They can turn reddish brown in the fall, but you’re still not out of the woods. You can have a reaction whether the leaves are green or red, dead or alive. Since urushiol covers the entire plant, the stems and roots should be avoided as well.

This entry was posted on Wednesday, June 13th, 2007 at 5:50 am and is filed under Skin Concerns. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.