We just found out today, a friend of ours was preserving butternut squash last night (she belongs to a co-op and gets large amounts of seasonal food)...and she had an allergic reaction to the skin of the squash and was quite frightened in fact! And sure enough on Wiki is a medical factoid about this, and to wear gloves while peeling squash!

There can be all sorts of weird contact reactions to things. One biggie is Downy type fabric softeners. I used to see people with rashes from that alone!