Immediately wash the area of the skin that was exposed with abundant amounts of running water.
Wash your clothes--pants, blouse or shirt, and socks--as well as shoes after you've become aware that you've been exposed to any of the plants. In addition, splash rubbing alcohol on the contaminated area (with the exception of the face). The oil in the plants, urushiol oil, which causes the rash can be neutralized this way.
Resist from scratching the ensuing rash as it can lead to neural dermatitis or an itch that continues even after reaction to the oil in any of the plants has stopped.
Reduce itching by running hot (not burning) water over the area of the rash for about five minutes, maybe longer. Running hot water over the area releases histamines in the skin and can help relieve itching for as much as eight hours.
Itching can also be reduced by applying warm or cold packs to the area in combination with calamine lotion.
If itching is unbearable, get a prescription for cortisone cream which is a great deal more effective for the treatment of poison ivy, poison oak or poison sumac than the over-the-counter kind.