For me, it was an annoying couple of pimples on my hand. Itched a lot, but nothing to get worried about. My eight
ten-year-old, though, broke out in a rash all over his face, with splotches on his leg and chest -- serious enough that we went to the dermatologist today. Diagnosis: an allergic response to urushiol, the active ingredient in Toxicodendron diversilobum, more commonly known as poison oak, no doubt from our trips through the woods last week at Hood Canal.
Update on additional facts I've learned:
- Urushiol can remain active for months, so multiple after-exposures are possible if you don't wash (with detergent) everything that came in contact with the plant. Apparently urishiol is easy to spot on an object, though: it oxidizes into a blackish lacquer upon exposure to air.
- Allergic reaction seldom occurs on the first exposure. The second exposure is the one to watch for, because the reaction can be quite severe. You can lose your sensitivity entirely if you are exposed often enough.
- People who are allergic are super-allergic. In one test, people developed a reaction after a thumb was pressed on the back of a non-allergic person who had been exposed three days earlier!
- The best article I found is here.