Zanfel: Very expensive, does what it says it will do but if you already have a bad rash, you're not going to cure the stuff overnight. I never have any luck once the rash actually breaks out.
Technu: Great stuff that's realtively affordable, will wash off the oil that is the root cause of the rash in the first place.
Ivy Block: Expensive, and
worth it. I use it before working anywhere near the stuff and follow up with a shower using Technu, or some other oil dissolving detergent.
PI, PO, and PS do not "spread" systemically but it is
very easy to spread the oil in the shower. When showering after an exposure, wash head to toe, in that order,
, making sure you wash/rinse all the way down to your toenails. I've showered and wound up with a mild rash on my feet the day after. Use cold/cool water for the initial wash down. As hot as you can stand it if the rash breaks out.
Most of the products that are labeled to use specifically on poison ivy rash are labeled with very specific instructions. Follow them to the letter and make sure you shake 'em up good 'cause most are suspensions that separate easily. Most have a specific time limit as to how long they are effective for. Know that when the time runs out for a product like Ivy Block, if you haven't washed the oils away by then, you are still in for an itchy 2-3 weeks. The single most important factor is time. Minimize time between exposure and thorough cleansing for best results.
Another good way to remove the oil from your skin is mechanic's hand cleaner. (Fast Orange, GoJo, etc.) If it can cut through the grime I accumulate in a day, it can surely handle a little Urishiol. Also, I wash down my equipment with citrus-based degreaser and my PPE/clothes with Simple Green is the washer.
I am extremely sensitive to the stuff and it is
everywhere in my neighborhood. I managed to process a large Red Oak post-Sandy that had 3 or 4 vines on it that the main runners were 4"+.
I tied the runners to the truck and pulled 'em off the tree, dragged them into the woods to die. Not impossible to deal with, especially after the leaves have fallen off for the winter. Getting close to the time I like to cut the vines with loppers too. After the plant has gone dormant all winter and used up it's root reserves, take a 1 ft section of the main runner out before the leaves begin to bud. I also used a mixture of glyphosate and triclopyr ( I think it was Round-Up's Poison Ivy/Tough Brush formula) and that did wonders to stop the new vines from growing. Only the big 'uns left and I'm working on those now.
Leaves of three, fear me.