As the "ivy" climbs trees you may notice "hairy" roots that are brown or red in appearance.
It's best to keep your distance from all three of these plants. The oil, Urushiol, on the plants is the culprit that makes you itch and break out in blisters. If you think you've come in contact with one of these, wash the affected area with cool water and antimicrobial soap. Warm and Hot water spread the oils! It's also important not to use a washcloth, and to shower rather than bathe.
Make sure that all clothing is washed. If the oils are not removed from your skin, you can pass the rash from one person to another. Last but not least, animals can carry the oils on their fur as well. If your dog or cat is hiking with you, make sure that they are bathed properly. One more note: Do NOT burn these plants as you can be affected by the smoke that the produce!