Poison Ivy: “Leaves of Three, Let It Be” ©

 

Eastern poison ivy, photograph by the author.

Because of COVID-19 and the schools being closed, Boy Scout Troops can’t meet, and so for my readers who are Boy Scouts in the United States, this article can help you with the plant identification requirements for First Class.  When I was a Scoutmaster, this was the first plant I taught the scouts.  For other plant identification articles go HERE – Author’s Note

I was walking through Stiglmeier Park, in Cheektowaga, New York, on Memorial Day, and it occurred to me that “April showers, bring May flowers” and poison ivy!  The poison ivy was everywhere!

And speaking of everywhere, poison ivy is found throughout the United States and Canada, except in Alaska and Hawaii: poison ivy also does not grow well in the desert, in the rainforests or above 4,000 feet (1,220 meters)¹.  There are two types of poison ivy that are found across this vast range: eastern poison ivy, or toxicodendron radicans (L.), to use its scientific name, and western poison ivy, also known as, toxicodendron rydbergii. 

 

Distribution of eastern poison ivy, toxicodendron radicans (L.), from United States Department of Agriculture, Natural Resource Conservation Service, “Eastern Poison Ivy”.

 

Distribution of western poison ivy, toxicodendron rydbergii, United States Department of Agriculture, Natural Resource Conservation Service, “Western Poison Ivy”.

  

Insects, birds, mammals, amphibians, and reptiles welcome poison ivy plants, as some can eat poison ivy, some find the little white berries delicious and some use the plant as shelter.  Black bears, raccoons, and white-tailed deer all browse on poison ivy, eating the leaves, the stems and the berries². 

 

An excerpt from An Illustrated Guide to Northeastern Forest Trees, page 6.

However, humans consider it to be a noxious weed, since most people are allergic to the clear, resinous oil, called urushiol (pronounced u-ROO-she-ol), which is found in the leaves, stems and roots, of the ivy.  Urushiol oil is sticky, and it will contaminate everything that touches the plant, your skin, clothes, tools, shoes, and jewelry.  If you touch something that has been contaminated with urushiol oil, and then touch your skin, you will end up with a rash,  Urushiol oil will even stick to your pet’s fur, once I got a bad case of poison ivy rash from petting my cat, who had walked through a patch of poison ivy!

 

Urushiol-induced contact dermatitis on the arms after 72 hours from contact with poison ivy, July 16, 2009, photograph by Larsonja, Wikipedia

A poison ivy rash is a case of contact dermatitis, or in plain English, an allergic reaction to the urushiol resin.  According to the Mayo Clinic, your skin must come into direct contact with the urushiol oil to develop a rash.  If the rash is in a straight line across your skin, that means that you brushed up against some poison ivy.  However, if your rash is more spread out, you probably encountered the urushiol oil from your clothing or a tool or your pet.  A poison ivy rash is not contagious, and you can’t catch it from someone else, unless they still have the plant’s oil on their skin or clothes.

A rash usually develops within 12 to 48 hours of exposure to urushiol oil and can last two to three weeks.  Doctor Eric Weiss writes in A Comprehensive Guide To Wilderness & Travel Medicine, that your risk of developing a rash increases with every exposure to poison ivy and urushiol oil.  He also writes that the rash “starts as red, itchy bumps, followed by blisters that may become crusted”.  The more urushiol oil that you encounter, the more severe will be the allergic reaction and the sooner a rash will develop.  The rash will appear later in areas where the urushiol oil was less concentrated.  This is the reason for the misconception that the oozing, poison ivy blister fluid spreads the rash; however, blister-fluid will not spread the rash! 

It is not a good idea to scratch the blisters though, as it can lead to secondary skin infections and according to Dr. Weiss will increase the itchy feeling!

According to the Mayo Clinic, the symptoms are:

·       Redness

·       Itching

·       Swelling

·       Blisters

·       Difficulty breathing, if you've inhaled the smoke from burning poison ivy

And you should see a doctor if

·       The reaction is severe or widespread

·       You inhaled the smoke from burning poison ivy and are having difficulty breathing

·       Your skin continues to swell

·       The rash affects your eyes, mouth, or genitals

·       Blisters are oozing pus

·       You develop a fever greater than 100 F (37.8 C)

·       The rash doesn't get better within a few weeks

Dr. Weiss, in his A Comprehensive Guide To Wilderness & Travel Medicine, states that if left untreated the rash will generally clear up on its own in about two weeks.  He suggests that oral antihistamines, like Benadryl®, when 25 to 50 mg are taken every four to six hours, will help to relive the itchy sensation, though it might leave you drowsy.  Also, and from past experience I agree whole-heartedly with this, calamine lotion and over-the-counter steroid creams, like a 1% hydrocortisone cream, are not highly effective.

The best way to prevent poison ivy, and this is coming from someone who is really allergic to it, is to never, ever come in contact with it!  Which means that you have to learn to identify the plants and always be on a lookout for them, you have to be careful about letting your pets roam through areas where poison ivy grows and you have to be careful about what you burn, that vine with fuzzy roots, should never, ever go into the fire!  Also, where protective clothing when you are out in areas where there is poison ivy, you should wear long pants, a long-sleeved shirt, and closed-toe shoes.

 

An old saying that can help you identify poison ivy, graphics by the author.

“Leaves of three, let them be”.  As the first line of the saying says, the first thing that you should look for, is a plant with three leaves.  Also, many times, but not always, the leaves look like mittens with “thumbs”; sometimes the “thumb” is on the left, sometimes on the right and sometime on both side of the leaf.

 

An example of “thumbs” on poison ivy leaves, notice that most of the leaves have “thumbs” but not all do.  Photograph and graphic by the author.

“Berries white, run in fright”.  In the fall, the fruit of a poison ivy plant can be seen as a spray of white berries.  Also, in the fall, the leaves of a poison ivy turn bright red.

 

Poison ivy growing up a tree, photograph by the author.

“Hairy vine, no friend of mine”.  Sometimes, poison ivy grows along the ground, like in the pictures above, however sometimes it grows as a vine up along the trunks of trees.  When that happens, even when there are no leaves, you can tell it is a poison ivy vine because of the hairy roots of the vine

 

Poison-ivy vine located in Mount Airy, NC, October 22, 2005, photograph by Melissa Wilkins, Wikipedia.

Here are some other things to look for which will help you to identify poison ivy

 

Graphic by the author.

So, what should you do if you think that you have been exposed to poison ivy?  Just like with COVID-19, you need to wash any part of you that might have been in contact with poison ivy, with plenty of soap and water; and warm water is better than cold water, unless cold water is all that you have.  Scrub under your fingernails too, as this will help to keep the rash from spreading.  And since the urushiol oil binds to you skin within 30 minutes³, you need to wash it off as soon as you can.  If you can’t, for whatever reason, wash it off within 30 minutes, the Mayo Clinic says that even washing after an hour has passed, will help reduce the severity of the rash⁴.  You will also need to wash any clothes, shoes, shoelaces or outdoor tools and gear that might have come into contact with the poison ivy, since the urushiol oils can stay active and potent for years⁵.  The best way to wash contaminated clothes, according to the Mayo Clinic, is with a washing machine.  If you suspect that your clothes have urushiol oil on them, handle them carefully so that you don’t transfer the oil to yourself, your other clothes, your appliances, furniture, etc.  Also, if you suspect that your pet might have encountered poison ivy, give them a bath, to remove the urushiol oils from their fur, so that it doesn’t spread to you.  Always wear long rubber gloves when you bathe them, if you think they might be contaminated.

So next time you are out and about in the wilderness, keep in mind that the spring weather is bringing out more than flowers and steer clear of the poison ivy!

I hope that you continue to enjoy The Woodsman’s Journal Online and look for me on YouTube at Bandanaman Productions for other related videos, HERE.  Don’t forget to follow me on both The Woodsman’s Journal Online, HERE, and subscribe to BandanaMan Productions on YouTube.  If you have questions, as always, feel free to leave a comment on either site.  I announce new articles on Facebook at Eric Reynolds, on Instagram at bandanamanaproductions, and on VK at Eric Reynolds, so watch for me.

That is all for now, and as always, until next time, Happy Trails!

Notes

¹ Eric A Weiss, MD, A Comprehensive Guide To Wilderness & Travel Medicine, 3^rd Edition, page 135-136

² Tara Wildlife, “Wildlife Value of Poison Ivy”, December 21, 2016,

³ Eric A Weiss, MD, A Comprehensive Guide To Wilderness & Travel Medicine, 3^rd Edition, page 135-136

⁴ So just remember soap and water are your friends!  And either a small bar of travel-sized soap, in a Ziploc® bag, or a bottle of biodegradable, phosphate free, pH neutral, liquid soap -- like Sea To Summit Wilderness Wash, should always be included in your first-aid kit when you adventure in the wilderness.

⁵ Mayo Clinic Staff, “Poison ivy rash”,

Sources

Mayo Clinic Staff, “Poison ivy rash”, [Mayo Foundation for Medical Education and Research (MFMER), © 1998-2020] https://www.mayoclinic.org/diseases-conditions/poison-ivy/symptoms-causes/syc-20376485, accessed May 28, 2020

Nelson, Tina and Lanza, Janet; An Illustrated Guide to Northeastern Forest Trees, [Marginal Media, Bioguide No. 4, 1983]

Tara Wildlife, “Wildlife Value of Poison Ivy”, December 21, 2016, [Tara Wildlife, © 2020], http://www.tarawildlife.com/wildlife-value-poison-ivy/, accessed May 28, 2020

United States Department of Agriculture, Natural Resource Conservation Service, “Eastern Poison Ivy”, https://plants.sc.egov.usda.gov/core/profile?symbol=TORA2, accessed May 27, 2020

United States Department of Agriculture, Natural Resource Conservation Service, “Western Poison Ivy”, https://plants.sc.egov.usda.gov/core/profile?symbol=TORY, accessed May 27, 2020

Weiss, Eric A, MD, A Comprehensive Guide To Wilderness & Travel Medicine, 3^rd Edition [Adventure Medical Kits, Oakland, CA, 2005], page 135-136

Wikipedia, “Toxicodendron radicans”, May 29, 2020, https://en.wikipedia.org/wiki/Toxicodendron_radicans, accessed May 27, 2020