Oh man, where do I start....
Things I'm allergic to by skin contact,
Iodine-oddly enough I can ingest iodine in salt/seafood with no problems, it's only by skin contact that it hurts me.
Hmm, I think that's the only one that I actually have to come in to contact with for it to affect me.
Things that I'm allergic to the mere presence of, never mind skin contact.
Aloe. Which is in *everything* now, so widespread that it's really hard to avoid. Of course when I tell people that I have skin allergies the very first thing that they try to do is slather aloe on me...and if *one* *more* person tries to tell me that I *can't* be allergic to it I won't be held responsible for my actions.
Scented things. This includes cologne, perfume, aftershave, hand/skin lotion, bath/hand soap, laundry detergent, and fabric softener. The only bath/hand soap that I can use is Ivory, and I have to use baking soda for laundry detergent. I also have to spend about 20 minutes cleaning out the machines in the community laundry room where I live before using them.
Bleach/chlorine.
Hydrochloric acid. No, seriously, minute amounts are used as an emollient in some lotions/soaps/cremes/ointments, and most people are just fine with it. Makes me come out in blisters.
Foods that I'm allergic to.
Dairy. Most people who say that they are allergic to dairy actually have lactose intolerance, which isn't quite the same as a true allergy. I have that too, but I also have an actual allergy to dairy products on top of that.
Orange and red food coloring/dyes.
Citrus, tomato, spinach, strawberries, cucumber, onion, most spices.
And the real absolute kicker... generic/house brand forms of diphenhydramine hydrochloride (benadryl). You know, the stuff you take to help counter allergic reactions. (It's actually the dye in the generic forms that I'm allergic to, so I can still use the name-brand, thank heaven.)