Sarah, one of the young ladies in my practice in her late teens, sat on the exam table looking just a bit like a picture I once saw of a frog that had been stung by a few dozen bees. Her eyes were almost swollen shut. Her ears, lips and cheeks were puffy and red. The transformation of this normally wholesomely pretty young lady was striking to say the least. And she was itching terribly almost from head to toe.
Yes, she had inadvertently walked through a good patch of poison ivy, to which she was extremely allergic. About 80-85% of people are allergic to poison ivy and 15% are extremely allergic. Poison ivy causes a reaction that medically is called allergic contact dermatitis (ACD). Other plants such as poison oak and poison sumac can cause similar reactions but are not as incredibly common to Tennessee woods, yards and hillsides as poison ivy.
When the plant oils come in contact with human skin, they begin to trigger an allergic reaction which usually starts to show up about 48 hours later. Within 20-30 minutes of contact with human skin the oil of the poison ivy plant is essentially neutralized. Until that point, if the oil is on your hand, for example, anywhere else you touch can get the reaction because the oil is transferred. So if you know you’ve come in contact with poison ivy, the quicker you can wash it off with soap and water the better, ideally in less than 10-15 minutes.
The allergy-producing oil of poison ivy does not get neutralized when it is on clothes, other inanimate objects, or pet fur. So if those things have been in poison ivy, even days previously, and come in contact with your skin, you can have a new poison ivy outbreak. So pets, clothes, etc. that have come in contact with poison ivy need a good washing to avoid future trouble.
One myth is that the fluid from poison ivy blisters can spread the poison ivy, or that you are contagious when you break out in poison ivy. By the time you are getting blisters or a rash the poison ivy oil has long ago been neutralized by your skin. The rash just sometimes appears in different places over several days due to different amounts of oil and thickness of the skin in those areas. It’s not truly spreading in any contagious manner.
The appearance of poison ivy plants is pretty well known to most who venture into woods and fields. The typical three-leaved shiny plants with notches on the leaves and growing either as a ground vine or a hairy vine going up a tree is easy to recognize. The five-leaved vines on many trees are the generally harmless Virginia Creeper, not a five-leaved poison ivy variant. Just Google poison ivy, oak and sumac images to get a refresher in what these look like.
So suppose despite your best efforts, you’ve gotten into poison ivy and are breaking out. If it’s mild, just use cool compresses, a cortisone cream (or Sarna or Calamine or whatever your favorite topical anti-itch cream is), and an oral Benadryl when you’re going to try to sleep. Don’t take hot showers or use lots of soap once the rash has started; you want the natural oils in your skin to remain and reduce the itching. Oatmeal baths can be soothing as well.
But if you have a more intense outbreak, see your doctor and get either a shot of cortisone or an oral course of it. The typical length of a poison ivy outbreak is two weeks, so the treatment generally needs to be for that length of time.
Even with poison ivy around, it’s worth a little risk to get out and enjoy the beautiful creation God has put around us here in East Tennessee. Just get to know the appearance of these bad boy plants, keep a little distance, and if they still manage to jump on you, deal with them smartly and as quickly as possible.