What is calamine lotion? It still seems to be the standard treatment for ivy poisoning, but what is “calamine?” Turns out it is just plain old zinc oxide with a trace of iron oxide (rust) that gives it a slightly pinkish color. The only good it does is to dry out the oozing blisters (that don’t ooze if you don’t scratch them) and providing protection from additional sun damage. If it does relieve the itching, it is mostly because you think it does. Enlarge the photo on the left and you will see the label only claims it to be a “skin protectant” and a “drying lotion.” Do nothing and the ivy poisoning will disappear in about a week on its own. Treat it aggressively with calamine lotion and it will be gone in seven days (so they say).
Ivy poisoning is an allergic reaction, so nothing seems to happen the first time you touch the plant. But you can only get away reaction-free once. You are now sensitized and will react to it from now on, for the rest of your life. Some people are so sensitive they react to the dormant, buried roots in winter.
Growing up, we occasionally took homeopathic doses of the poison ivy oil as tiny white pills, about the size of sesame seeds, throughout the summer as a prophylactic against ivy poisoning. They made no difference I could see, and I suspect they only served as a reminder to avoid the plant in the first place. We also heard the rumor that eating a poison ivy leaf would provide protection from a future outbreak, but no one was brave enough to try it, not even Eddie Vetter who suffered the most from ivy poisoning. We never thought ahead, anyway, about anything.