How To Deal With Poison Ivy on the Appalachian Trail

I swear the poison ivy situation on the Appalachian Trail seems to get worse with each passing year. Shenandoah National Park is a veritable poison ivy garden, and just the other week I found myself dodging and weaving to avoid some of the stuff drooping over the trail at face level near Delaware Water Gap.

Back in the golden days of my youth, I would wander onto the trail wearing shorts and short sleeves, not a care in the world about these flesh-eating murder plants. Sigh. I was so young and innocent back then. I had never reacted to poison ivy before and assumed I never would, so I did stupid things like walk through poison ivy, sit in poison ivy, and brag about how I was immune to poison ivy.

You know where I’m going with this. I react to it now and I take it a lot more seriously.

Poison ivy is common throughout most of North America, so if you have ambitions to spend time outside anywhere on this continent, it’s worth learning something about how to identify the plant and how to prevent and treat poison ivy rashes. If you’re like me and you weren’t born with a working knowledge of this plant, this article is for you.

Ed. note: We’re hikers, not doctors. The material on this site is for informational purposes only and is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of a qualified health care provider with any questions you may have regarding a medical condition. 

Identifying Poison Ivy

Remember the old adage, “leaves of three, let it be.” Looking for poison ivy’s characteristic three-leaflet clusters is the easiest way to identify it. Lots of other, much friendlier plants also have leaves of three, of course, but when in doubt just err on the side of caution.

Beyond just counting leaflets, you can look for other telltale signs to distinguish it from other species. The leaflets often have a distinctive serrated edge and the middle one tends to have a longer stem than the two flanking it. It may or may not be shiny. It may or may not be green depending on the season.

Poison ivy takes many forms, from small, delicate-looking plants peeking out of the herb layer on the forest floor to thick, hairy vines creeping up the sides of trees. The leaves are red and shiny when young and turn green as they mature. They may either be dull or have an oily sheen. In summer you may find the plant sporting clusters of hard, whitish berries. In autumn, the leaves turn beautiful shades of orange and red once more.

There’s a lot to look out for, but once you have the basics—three leaflets, possibly serrated, longer middle stem, hairy vines on tree trunks—you’ll be equipped to ID poison ivy in all its forms. I encourage you to look at lots of pictures of this plant. Save some to your phone before your hike; with practice, spotting it will become a lot easier.

Every part of the plant—leaves, stalks, berries, roots, vines—causes rash, so you don’t want to touch any of it.

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Poison Ivy Habitat

Poison ivy likes edge habitats: areas of transition between forest and meadow where there’s fertile soil and plenty of sun. Be extra cautious in areas where the trail moves between woodlands and grass, around trailheads and road crossings, and in places where the forest canopy is relatively open and lets a lot of sunlight through to the ground.

That being said, poison ivy can adapt to a wide range of conditions, so you might also find it in the midst of deep woods or a sunny-ass field. Who even knows! It’s part of the adventure, I guess!

Who Reacts To Poison Ivy?

About 75 percent of the population reacts to poison ivy. And even the ones who don’t react could start at any moment. Yes, there are a few chosen ones who go their whole lives crashing through the brush and never once get a rash. These favored children have been smiled upon by the heavens, and we must all put aside our spite and jealousy and try to be happy for them.

For the rest of us, it’s best practice to avoid exposure to poison ivy even if you’ve never had a reaction before. Why? Because the more often you’re exposed, the more likely you are to eventually react. More exposure can also lead to more severe reactions down the line, which is fun, so be careful.

What Does a Poison Ivy Reaction Look Like?

The rash that most people get from poison ivy is an allergic reaction to urushiol oil, a resin found throughout the plant from roots to leaves. As stated above, you can get a reaction from touching any part of the plant thanks to urushiol oil. The rash typically looks like clusters of red bumps and blisters that are intensely itchy. The blisters may eventually burst, ooze, and then scab over. And the whole area may or may not swell up. Again, so fun.

Most people react within four to 48 hours of being exposed, but more like two to three weeks if it’s your first reaction ever. I’m getting these numbers from the American Academy of Dermatology Association (AADA), by the way, if you want to read more about this.

The rash itself isn’t contagious, but urushiol oil, that sneaky bastard, is hard to get off and spreads easily. (Many people even react after weed-whacking or burning poison ivy, that’s how spready the stuff is.) If you don’t wash the oil off your skin and clothing, it can spread to other parts of your body or other people, causing more rashes. Pets can transfer urushiol from their fur to your skin, so those of you hiking with your furry best friend should be extra cautious.

How To Treat Poison Ivy During Your Hike

An ounce of prevention is worth a pound of cure, and we hikers know how valuable a pound of anything is out on the trail. Your best defenses are knowing how to identify poison ivy, keeping a weather eye out for the stuff any time you step off the beaten path, and wearing long pants and sleeves to keep it off your skin.

The first step in treating a poison ivy rash is recognizing that that’s what it is. The first time I reacted, I thought I just had a series of really weird, especially uncomfortable bug bites. After cheerfully reducing the area to a patch of raw, bleeding flesh through incessant scratching (a treatment plan endorsed by no one), it was still unbearably itchy, and that’s when I started to get wise and slapped some gauze and leukotape over the damage zone.

Important: Wash Everything in Sight

As soon as you know you’ve been exposed to poison ivy, you should wash the affected area thoroughly (but gently!) with rubbing alcohol. Those little alcohol prep pads in hiker first aid kits are ideal for this, or you could use alcohol-based hand sanitizer in a pinch. (Experts also recommend dish soap, specialized poison ivy soap, and laundry detergent for washing off urushiol oil, but most hikers don’t carry these items in their packs.) Rinse with cool or lukewarm water after.

This is fairly inconvenient for thru-hikers, but you should also wash your clothes as soon as possible, as they can also carry and spread urushiol. Really anything that possibly came in contact with the poison ivy, from clothing and gear to pets, ought to be washed if possible.

I’ll be honest, I’ve never tried washing my pack to get rid of urushiol oil and rarely have been in a position to do laundry within 24 hours of exposure while backpacking, and I’m still alive and kicking. Just do your best and work with what you’ve got, same as always on a thru-hike.

Why wash? Quick washing can prevent or at least reduce the severity of rashes. You’ll also avoid spreading the oil to other parts of your body or other people.

The Waiting Game

After washing, it’s mostly a waiting game. If you do react, you can apply hydrocortisone cream to knock down the itching and take benadryl orally to relieve symptoms at night. Other than that, it will just take time and patience for the rash to heal.

Scratching—whether it’s poison ivy, a bug bite, or something else—is a great way to aggravate the rash and introduce secondary infections, so don’t do that. It’s nice to leave the rash uncovered so it can air out, but if scratching becomes irresistable, consider covering it with a bandaid or some leukotape.

Most rashes go away within a week to 10 days.

When To See a Doctor

Get medical help as soon as possible if you’re having a severe reaction. Some things that qualify as “severe” in this context (according to the AADA):

• Difficulty breathing or swallowing
• A rash around one or both eyes, your mouth, or on your genitals
• Swelling on your face, especially if an eye swells shut
• Itching that worsens or makes it impossible to sleep
• Rashes on most of your body
• A fever

You should also see a doctor if your rash persists longer than 7 to 10 days or if you think it’s become infected. It’s also worth a trip to urgent care if you’re not certain the rash was caused by poison ivy (or its urushiol-laden cousins, poison oak and sumac) just to rule out something more serious.

Helpful Tips for Hikers

• Save pictures of poison ivy to your phone to aid in field identification
• Look hard at every plant when stepping off trail to go to the bathroom or make camp
• IMPORTANT: Poison ivy vines can grow up the sides of trees and then shoot out leafy branches that are easily mistaken for innocent tree branches drooping into the trail at face level. All foliage hanging in your path should be thoroughly interrogated before you brush against it.
• Trekking poles can help push poison ivy out of the way with minimal contact exposure.
• Dog owners should be extra vigilant to keep their pets from running through poison ivy. Dogs don’t react to poison ivy themselves, but they can carry the oils back to you on their fur.
• Alcohol prep pads are lightweight and can be used to wash urushiol oil off your skin after exposure. Rinse with cool water after.
• Cover poison ivy rashes with leukotape to keep yourself from scratching.

Poison Ivy Fun Facts!

Did you know…

• Poison ivy is a distant cousin of the cashew nut and the mango. Wow!
• Urushiol, the oily resin in poison ivy that most of us are allergic to, is the very same oily resin that most of us are allergic to in poison oak and poison sumac, two close poison ivy relatives.
• Poison ivy is actually three separate species:
  • Toxicodendron radican is native to North America and Asia. It can grow as a shrub, climbing vine, or trailing vine
  • Toxicodendron rydbergii is native to most of Canda and the US except the southeastern states and New Jersey, Delaware, and California. It grows as a shrub
  • Toxicodendron orientale is a species of poison ivy native to East Asia
• Urushiol can remain potent for up to five years, apparently. Dead plants can still cause an allergic reaction!
• Poison ivy is a native North American plant. It’s good to know there’s at least one native species thriving around here, even if it is, objectively, the worst thing ever

Featured image: Graphic design by Zack Goldmann.