I get the same thing, but not on the underside of my arms. My hands get rlaley dry, especially between the fingers, and at the joints, usually the skin breaks. I have to wash the dishes with rubber gloves during the winter (that helps keep it from getting worse) but it's just chapping. My mother is a nurse and always had the same thing. Mine has gotten worse as I've gotten older. Mine is not itchy at all, just rlaley dry and that makes it feel irritated, but it's not like poison ivy. I think it is just because I am fair skinned (I am not particularly sensitive to a lot of other things. I also get a patch of dry flaky scalp in the front of my hair, near the forehead hairline, every Winter I use T-Gel shampoo on it a couple of times a week to keep it at bay, but it never goes away all the cold months of the year.) I rlaley think it is the drier, Winter air that causes the problem.I recently discovered aveeno brand hand lotion, it does temporarily relieve the problem and make the skin more pliable and less vulnerable to breaking open. (Gold Bond hand cream and Sally Hansen hand cream also work well, but I like Aveeno the best. You can buy a generic version at the drugstore too and save a few bucks.) Also sometimes washing your hands with gentle soap before bedtime (like dove) then rinsing and covering the worst spots with neosporin or aquaphor (made by eucerin) can help. Nighttime is a good time to rlaley moisturize your hands. You can even buy cotton gloves to wear at night, lotion up rlaley well and slip them on. Doing this consistently will soften up your hands some. I don't think there is a cure all for it though. Always carry hand lotion with you.Good luck!