Poison Ivy

Preventing and treating the symptoms of poison ivy

By Melissa Cardin

The weather is getting warmer and that means more time outside to partake in some of the great things the season brings. But nothing puts a damper on enjoyment more than a case of poison ivy. If you plan on spending any time outdoors this season, it’s important to know how to avoid poisonous plants.

Ron Christie, master gardener with the University of New Hampshire Cooperative Extension said here in New England we don’t have to worry about poison oak. It doesn’t grow in New England at all. Poison sumac lives in wet, soggy areas, which minimizes the average person’s exposure to it. But poison ivy can be found everywhere.

“It typically grows on roadsides, where the soil is poor, especially on roads by a wooded area,” Christie said. “Poison ivy is a robust plant, even with global warming. The more carbon dioxide in the air, the better the plant does.”

He cited a study done in Virginia that showed poison ivy survived better in urban areas because of the higher levels of carbon dioxide.

The appearance of poison ivy can change through the year, so it’s important to know what it can look like.

“It comes up green, the leaves stay green all summer, then can change to red in the fall,” Christie said. “The leaves drop off in the fall, but it’s important to remember that both the vine and the leaves have the oil on them all year.”

What causes a poison ivy rash?

A poison ivy rash is caused by the urushiol (pronounced oo-ROO-shee-ohl) oil that is in the sap of the leaves, stems and roots of poison ivy, oak and sumac. The oil actually is inside the plant, but the leaves and stem of the plant can be easily broken by stepping on them, insects or animals that eat it, or just by blowing in the wind.

It’s very common to come in contact with urushiol while walking in the woods or weeding the yard. However, urushiol is sticky. It can stick to pet fur, garden tools, toys or clothing. It’s possible to pick it up from a dog that ran through it or a ball that rolled into the woods. Urushiol is stable and can still be potent several years after it was transferred from the plant.

How does the rash develop?

The medical term poison ivy dermatitis is a delayed hypersensitivity reaction. This means your body reacts slowly. It typically takes 12 to 48 hours for a rash to show, though it can be delayed even more if it is the first time contact is made. It will develop much faster with repeated contact.

If you think you’ve been exposed to urushiol, you should know that it takes only 10 minutes to penetrate the skin. To prevent any further spreading, you should:

• Clean your exposed skin with rubbing alcohol (isopropyl). Don’t return to the yard or woods the same day. The alcohol removes the resin, but it also makes your skin more sensitive to a second exposure the same day.
• Wash your skin with lots of cold water to remove the urushiol completely. Hot water will open your pores and allow more of the oil to penetrate. Don’t use soap. It can move the urushiol around on your skin.
• Take a regular shower with soap and warm water.
• Wear disposable gloves and wipe your clothes, shoes, tools, etc., with alcohol and water.

What can I expect the rash to look like? How do I treat it?

Poison ivy dermatitis is an allergic skin rash. It causes a red, uncomfortable itchy rash marked by lines, streaks, blisters or hives. Some blisters may leak fluid.  However the rash, blisters and liquid are not contagious. They don’t contain urushiol, and you cannot spread poison ivy by touching the rash. Once the urushiol has soaked in, it can’t be spread from one area of the body to another.

The rash will last for about 14 to 20 days. Benadryl can be given to control the itch, and your doctor might prescribe an anti-itch medication as well. Heat will make the itching worse, so use cool compresses to help. You can also use a mild hydrocortisone cream. If blisters form, you can use calamine lotion, baking soda, or Aveeno (oatmeal bath) to help treat them. Wet-dry compresses are also effective in treating the blisters.

What do I do if I want to remove some that I’ve found on my property?

“Don’t burn it!” Christie said. “It’s possible to breathe in the oil, which can cause lung problems.” The only treatment for that is steroid medication for a long period of time.

Christie’s preferred method is to pull it out by hand while wearing industrial gloves. He doesn’t recommend leather gloves, as the urushiol will seep through. It’s also possible to find a suit to protect your body and clothes at major hardware stores. He also suggests wearing a hat when you do this. You’ll have to repeat the process of pulling out the roots several more times until all the root matter is gone. If the roots remain, the plants will grow back.

“It’s also possible to use an herbicide on it,” Christie said, “but I would use a sponge or a brush to apply it to make sure that it’s all over the plant. It can take two to four treatments of this to completely get rid of it.”

If you’ve been fortunate enough to never have developed a rash from poison ivy, it’s important to know what you’re looking for, and how to treat it.

“Poison ivy can look like a plant, a vine or even a shrub,” Christie said. You’ve probably heard the adage, “leaves of three, let them be.” This is classic advice, but it’s also possible for poison ivy to have leaves in groups of five to nine.

“I suggest people look at pictures of it online to get a good idea of what it can look like.”

Melissa Cardin lives in Rochester with her husband, John, and daughter, Hannah. She holds a degree in social work and works as a freelance writer and as the case manager at Seacoast Family Promise in Stratham.