POISON IVY, OAK AND SUMAC: OVERVIEW
Rash from poison ivy:
Rash from poison ivy. Many people develop an itchy rash that causes lines or streaks that look like this.The itchy, blistering rash often does not start until 12 to 72 hours after you come into contact with the oil.
The rash is not contagious and does not spread. It might seem to spread, but this is a delayed reaction.
Most people see the rash go away in a few weeks. If you have a serious reaction, you need to see a doctor right away. Swelling is a sign of a serious reaction — especially swelling that makes an eye swell shut or your face to swell.
If you have trouble breathing or swallowing, go to an emergency room immediately.
Used with permission from American Academy of Dermatology