First Aid

Poison Ivy vs. Poison Oak: How To Spot These (Ob)noxious Weeds

by Three Bears Lodge on May 27, 2010 Category: Did You Know?

Do You Know What These Rhymes Have In Common?

“Leaves of three, let it be”
“Berries white, run in fright”
“Hairy vine, no friend of mine”

They remind us how to spot Poison Ivy and Poison Oak! All of these are useful rhymes which have certainly helped many a hiker escape painful exposure. Itchy red rashes, swelling, even blistering- an innocent hike in the forest can have very uncomfortable consequences if you don’t know what to avoid.

Here are some characteristics shared by Poison Ivy and Poison Oak:

  • Found in nearly every State in the United States

    Poison Ivy Leaflets

    Poison Ivy Leaflets

  • Grows at altitudes below 5,000ft
  • Deciduous
  • Grows as a bush or vine
  • Stems do not have thorns
  • Usually grow clusters of three ‘leaflets’
  • Leaflets can range in size from the length of your thumb to the length of your hand
  • Middle leaflet has a notably longer stem than the two side leaflets, though more obvious in Poison Ivy than Poison Oak
  • Depending on the season, leaf color can range from green to orange and even a dark purplish-red
  • Inconspicuous white spring flowers which usually produce clusters of small white blueberry-sized berries that turn red in late summer
  • Produce a rash-inducing oil called Urushiol
  • Toxic to humans but harmless to animals
  • All parts of the plant contain the toxins (leaflets, stems, and roots)
Poison Ivy Vine

"Hairy" Poison Ivy Vine

The most tell-tale characteristics of poison ivy are:

  • “Hairy” vines
  • Though Poison Ivy is not really an ivy, it’s often viney growth pattern can resemble ivy
  • Smooth or subtly toothed almond shaped leaflets that are sometimes irregularly lobed
Poison Oak Leaflets

Poison Oak Leaflets

The most tell-tale characteristics of Poison Oak are:

  • Leaf shape resembles an oak leaf, but it’s not a member of the oak family
  • Leaflets are duller green and usually more distinctly lobed or toothed than poison ivy
  • Mature leaflets are typically duller green than young ones
  • Leaflets have hairs on both sides, unlike poison ivy

Even a slight brush against theses plants can result in a skin reaction. The toxin is easily transferred from one surface to another and will remain potent for years if not thoroughly cleaned (imagine your exposed dog running through your house!). Also, symptoms can take 24-48 hours or even up to a week to show up, particularly if its your first exposure!  We recommend that you keep an eye out for these tell-tale signs to avoid contact!

Poison Oak Coloration

Poison Oak Coloration

Urushiol: Poison Ivy and Poison Oak’s Oily Toxin

Poison ivy and poison oak have one very essential thing in common: urushiol. This sinister substance is an oil secreted from the leaves, vines, stems, and roots of both plants. Upon contact with your body, urushiol immediately forms a chemical bond to the skin and causes an almost unstoppable allergic reaction. A fraction of the populace is unresponsive to the irritating resin, but don’t count on it: even an initial natural resistance to urushiol will eventually break down after repeated exposure from too many careless treks off the beaten path.  Caution: Smoke inhalation from burning Poison Ivy or Poison Oak can send you straight to the emergency room, avoid burning these plants at all costs!

Poison Oak Leaflets Showing Coloration

Poison Oak Leaflets Showing Coloration

To The Rescue: How to Treat Exposure

If you come into contact with either plant, the sooner you take care of it, the better. As the chemicals rub off your clothes onto other surfaces you run the risk of exposing yourself and spreading the oil. Urushiol is not water-soluble, so if you can, use rubbing alcohol or strong soap to cleanse the area of contact within the first ten minutes, then rinse off with cold water. As urushiol can remain active for years, you’ll want to wash any clothes, items, or furniture that may have come into contact with the invisible oily residue.

If you don’t catch the exposure immediately, your only choice is to treat the resulting itchy rash and blisters as best you can. While there are countless home remedies to relieve itching and pain, standard treatment options include oatmeal baths, baking soda pastes, calamine lotion, aloe vera, and a number of commercial products designed specifically for Poison Ivy and Oak. Of course, the best remedy is always prevention, so if you’re able to recognize and avoid poison ivy and poison oak, your experience in the mountains will feel the benefit!

Still not afraid of Poison Ivy and Poison Oak?
Click the links below to see just how bad these rashes and blisters can be…. (Warning! These graphic images are pretty disgusting!)

Leg Rash

Calf Rash

And if those two photos weren’t enough: Poison Ivy Rash Gallery

Poison Ivy Vine with Young Leaflets

Poison Ivy Vine with Young Leaflets