Please file under "Should have known better"
While out with my dogs last weekend, I went through a narrow trail that is constantly being invaded by Cape ivy (Delairea odorata). Without thinking, I grabbed the invading vine broke it off and pulled it out of the way. Only when I had that clump in my fist did I look at it and saw that it was not Cape ivy but another common vine - Toxicodendron diversilobum, commonly known as poison oak. Imagine my surprise.
Photo by Joseph M. DiTomaso.
I thought it had only gotten it on my arm and hand where I grabbed it so I avoided touching anything so as not to spread the urushiol oil which is what causes the itchy, bumpy allergic skin reaction and as soon as I got home, I washed my hands and arms with rubbing alcohol to dissolve the oil and washed it off. So far, that seems to have worked.
However, I guess I was not so lucky with other parts of my body. I thought I hadn't touched it but about 2 days later, the bumps showed up behind one ear. Then on one side of my face. Today, it is on my chin.
Poison oak is has started to grow pretty quickly this time of year and it is quite green, so you may not notice it if growing among other plants. Take my advice and look before you weed. Please see the UC IPM Pest Note about poison oak for information about identification, management, and what to do if you do meet it personally.