Is Poison Ivy Contagious?
This is a very commonly asked question. Yes, poison ivy is highly contagious but - and this is where the confusion sets in - it's only contagious while urushiol is present.
Urushiol is the oil found throughout the vine, root and leaves of the poison ivy plant. It's especially strong in the vine. The urushiol, found primarily beneath the outer skin of poison ivy, is what's contagious and causes the rash. Poison ivy is typically contracted by coming in contact with the leaves of the plant, or coming in contact with something that came in contact with it. The urushiol can be transported on clothing, animals, and even on your skin for a short period of time. While urushiol can remain active and contagious for a couple years, when it fully absorbs into the skin (usually within 15 minutes of contact) it can no longer be spread.
The best thing to do when coming in contact with poison ivy is to thoroughly clean all clothing and yourself. Taking a shower within 15 minutes of exposure is a good way to limit the poison ivy irritation, after that time it doesn't really matter because it has been fully absorbed into the skin. You cannot spread poison ivy by itching or scratching it, nor can you pass it to another person. You can, however, irritate areas of the skin that had mild contact with the plants urushiol thus making it appear as though the rash has spread. Even weeping blisters do not contain urushiol, therefore other than infection you cannot spread poison ivy once it has absorbed into your skin.