We may not typically think of poison ivy this time of year. It really seems like more of a summer worry. However, it’s the time in which we are usually doing a lot of yard clean up. You can be exposed to poison ivy raking leaves, picking up brush, stacking firewood, or even bringing firewood in for a fire. I thought this was a good time to talk about poison ivy. When you are not really thinking about it, you are more likely to be exposed.
What is a poison ivy rash?
A poison ivy rash is caused by an allergic reaction to an oily substance called urushiol. This reaction is called contact dermatitis. This oil is in the leaves, stems, and even the roots of poison ivy, as well as poison oak, and poison sumac. This is the most common allergic reaction in the U.S., with at least 85% of Americans being allergic to this oil to some degree, and about 10-15% of people being extremely allergic to it. The rash affects approximately 50 million Americans each year. You can also develop an allergy to this oil at any time in your life, so just because you have not broken out from poison ivy in the past, does not mean that you will not have a reaction the next time you come in contact with it.
The rash has a very classic appearance, with redness initially, followed by swelling, then blisters. The rash is associated with severe itching. The rash can range from mild to severe, depending on how much of the oil gets on your skin and how allergic you are.
How do you recognize that a plant is poison ivy, oak, or sumac?
You have probably heard the saying “leaves of three, let it be.” Poison ivy and poison oak both typically have three leaves. However, poison sumac typically has five or seven leaves. Poison ivy is a vine with a fuzzy appearance to the vine itself, but poison oak and sumac are shrubs. These plants grow everywhere in the United States, except Hawaii, Alaska, and some deserts in Nevada. They change colors in the fall, just like other leaves do, so they may not look the way you expect this time of year. Follow this link to see some pictures of the plants:
How do you get a poison ivy rash?
If you come into contact with the urushiol oil, you can develop the allergic skin reaction. The oil is colorless and odorless, so you don’t really notice that you have anything on you. It is sticky though, not sticky enough to make you feel sticky, but it really sticks to your skin. This oil is also very potent. The amount contained on the head of a pin can cause 500 people to have a rash!
Here are the different ways that you may come into contact with the oil.
- Direct contact – Touching the stems, leaves, roots, or berries of the plants
- Touching an object contaminated with the oil – It may be on your shoes after a walk, on the sleeve of your shirt or jacket, on the fur of your dog or cat, on tools that you used in the yard, on wood that was cut and stacked for the fireplace. The oil can stay active on a surface for several years without losing its potency.
- Inhaling smoke from burning plants – This can irritate or even cause damage to your nasal passages or lungs.
Is poison ivy contagious?
The poison ivy rash is NOT contagious. If you have a rash from poison ivy, the rash itself is not contagious. The fluid in the blisters does not contain the urushiol oil and it will not spread the rash. Just remember that it can be spread if you touch a person’s skin when they still have the oil from the plant on their skin, or if you touch their clothing before it has been adequately washed.
Next week we’ll talk about ways to prevent and treat the poison ivy rash.
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Dr. Anita Bennett MD – Health Tip Content Editor