This may become a series.
Found a good infographic today, on how to identify poison ivy — the bane of every Boy Scout and Scouter west of the Mississippi, and east of the Mississippi, too.
Poison ivy leaves turn a beautiful scarlet in the fall. This beauty prompted English ship captains dropping off colonists in New England to take the potted vines back to England.
It is my experience that, while everyone can become allergic and react to poison ivy, no one reacts on first serious exposure. If you’re in the woods, it’s good to know what this stuff is, and avoid it.
If you’re exposed, wash it off. Wash your clothes with some sort of oxidant (oxygen bleach for colors, or chlorine bleach if you don’t care); I use a 3:1 solution, water to chlorine bleach, to shower with after serious exposure. The active chemical, urushiol, remains active until it is reacted chemically or by ultraviolet light — and so a young Scout who gets some ivy sap under his fingernails can continue to spread the exposure everywhere he scratches, until his hands are really washed clean.
Study the poster, learn to identify the stuff. There’s a lot more to say.