when i was but a wee-rummy i used to get poison ivy all the time. as i wore glasses and was fat, i couldnt stand the stigma of coming to school pink from calamine lotion. as this was before the advent of calamine clear, i was forced to come up with my own home remedy. while most home remedies could very well be hit or miss and alot carry the placebo effect amongst them, this may or may not work for you...
mix aspirin and peroxide until you get a little pastey substance...apply, let dry and re-apply.
theoretically, the peroxide will help open the pores, allowing the salisylic acid (eats oil; see Clearsil) in the aspirin to eat the oil up...
ive also run the poison ivy under really hot water (as hot as you can stand) and then cut the nodules off with a sharp knife. i finish it off by pouring bleach on the area...yea, it hurts, and yea it could leave scars (though ive never had any), but dammit if it doesnt work.
oh, and oatmeal baths...looooooong oatmeal baths.
for prevention, ive found that Technu makes a soapy substance that you can use after being in contact with it. there is alsosupposedly a anti-poison ivy wipe out there as well that comes in individual packs for use in the field...im very excited about that.
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"It is a far, far better thing that I do, than I have ever done; it is a far, far better rest that I go to than I have ever known" - A Tale of Two Cities - Charles Dickens