With the end of summer, a lot of people are out enjoying the cooler weather and clearing land in preparation for the winter season. This means, unfortunately, it’s also the time of the year when those of us who enjoy spending some time outdoors have the best chance to come in contact with poison ivy.


With the end of summer, a lot of people are out enjoying the cooler weather and clearing land in preparation for the winter season.

This means, unfortunately, it’s also the time of the year when those of us who enjoy spending some time outdoors have the best chance to come in contact with poison ivy.

The plant, which can grow in different varieties as a bush, vine or is attached to trees, is more prevalent in Delaware than its cousins, poison oak and poison sumac.

It is best identified by its shiny, three-lobed leaves, which has given rise to the reminder, “Leaves of three, let them be.”

And just a little contact with the oils on the plant leaves can cause skin reactions ranging from merely annoying to incredibly irritating, said Dr. Joseph F. Andrews of Delaware Dermatology in Dover.

Andrews took a few minutes to talk about this nuisance plant, how its poison works, and how to best get relief from the rash and itching it causes.

1. How does poison ivy give people so much trouble?

“It’s the fat from the plant,” Andrews said. “When it comes in contact with skin, it causes an allergic reaction.”

The scientific designation for the poison ivy bush is Toxicodendron radicans, which is Greek for “poison tree.” That name itself should serve as a warning the plant has noxious qualities. The fat, known as urushiol, actually an oleoresin, is contained in the plant’s sap and coats its leaves.

Urushiol causes the common rash, blisters and skin eruptions that develop after contact with the plant, Andrews said. People most commonly see it when they unknowingly walk through a patch of the plant, causing red streaks across the legs. That’s one good reason why not to wear shorts when trekking through the woods.

2. You don’t have to touch it to get it.

“You may have heard this in Boy Scouts, and I didn’t believe it back then,” Andrews said, “but you can walk right past poison ivy and get [a reaction from] it.”

That’s particularly true if you’re out on a windy day, Andrews said. The wind picks up minute droplets of the urushoil and blows them through the air. If they land on your skin, you’ll have an allergic reaction.

The phenomenon is called airborne dermatitis, Andrews said. Because the urushoil is particularly hardy, people also can get it on their skin — or even inhale it — if they burn contaminated wood.

“The thing is, if the resin gets in the wood, it can stay there,” he said. “When it burns, it aerosolizes and if you’re exposed, you can get airborne dermatitis.”

In addition, people can pick up the oils from their animals, especially if the family dog has been cavorting in the woods. The oil can rub off on their fur and humans can pick it up when handling the dogs.

The same cautions apply when handling clothing that may have been exposed to urushoil, as the oil can rub off on the hands.

3. It’s important to act quickly if exposed to poison ivy.

The best thing to do is not come in contact with the plants at all. In addition to wearing long pants, people should wear long sleeves and consider wearing gloves, especially if clearing land where poison ivy may be present. A hat will prevent scalp exposure and safety goggles can help keep the urushoil from getting in the eyes.

Eventually, untreated poison ivy contact will cause large blisters to form, Andrews said. The agony of poison ivy contact is made only worse when the blisters start to ooze, although that in itself does not cause additional spread of the urushoil.

“That’s not a reaction,” Andrews said. “That’s just tissue fluid, and it doesn’t cause the problem.”

But reacting quickly to contact with poison ivy is essential to preventing the worst of the problems.

“If you’re exposed to the allergen, you have about 10 minutes to wash it off,” he said. “If you go in quick and wash with soap and water, there’s a pretty good chance you won’t react. Ten minutes or longer, the chances are you will.”

4. Treatment of poison ivy contact can vary.

Most symptoms appear within 24 hours of exposure, Andrews said.

A lot of people use calamine lotion, which helps soothe irritated skin, but that treats only the symptoms, not the underlying cause. Hydrocortisone creams also are good in mild cases of urushoil exposure, but aren’t as effective for severe cases.

Other home remedies include taking Benedryl to help treat the itching, plus cool compresses, which also help with the skin irritation.

“But stay away from hot showers,” Andrews warns. “They make it worse.”

There are other, prescription-strength medications that help.

“Your problem will improve while you’re on the medication, but when you’re off it, the problem can get worse. That’s a rebound phenomenon. The biggest problem is some people are not treated with high enough doses for a long enough time.”

In more complicated cases, topical or even oral steroids can help.

5. Some people are more sensitive to poison ivy than others.

Poison ivy’s urushiol oil is extremely potent, and only one nanogram (a billionth of a gram) is needed to cause a rash. Even if you’ve never broken out you cannot assume you are immune as the more often you are exposed to urushiol, the more likely it is that you will break out with an allergic rash.

Depending on sensitivity to the urushoil, some people may see little or no effect, which others may have what Andrews calls a “rip-roaring reaction.”

Upward of 90% of the population develops an allergy to it.

Email Jeff Brown at jeff.brown@doverpost.com.