Common Myths about Poison Ivy / Poison Oak / Poison Sumac:
Myth: Poison Ivy rash is contagious. -- Rubbing the rashes won't spread poison ivy to other parts of your body (or to another person). You spread the rash only if urushiol oil -- the sticky, resinlike substance that causes the rash -- has been left on your hands.
Myth: You can catch poison ivy simply by being near the plants. -- Direct contact is needed to release urusiol oil. Stay away from forest fires, direct burning, or anything else that can cause the oil to become airborne such as a lawnmower, trimmer, etc.
True: "Leaves of three, let them be." -- But not the whole story: Poison sumac has 7 to 13 leaves on a branch, although poison ivy and oak have 3 leaves per cluster.
Myth: Do not worry about dead plants. -- Urushiol oil stays active on any surface, including dead plants, for up to 5 years.
Myth: Breaking the blisters releases urushiol oil that can spread. -- Not true. But your wounds can become infected and you may make the scarring worse. In very extreme cases, excessive fluid may need to be withdrawn by a doctor.
Myth: I've been in poison ivy many times and never broken out. I'm immune. -- Not necessarily true. Upwards of 90% of people are allergic to urushiol oil, it's a matter of time and exposure. The more times you are exposed to urushiol, the more likely it is that you will break out with an allergic rash. For the first time sufferer, it generally takes longer for the rash to show up - generally in 7 to 10 days.
Source: http://poisonivy.aesir.com
"Great, my cases will just get worse and worse. This is the 5th time I get it in 3 months - since moving back into the house, April 1st, 2009."