if you are allergic to most sunscreens, the least allergenic potential are ones that contain zinc or titanium dioxide - no worries, there are better formulations today so you won't have that white (or bright orange) paste across your nose.
Neutrogenia Sensitive skin is one....i dunno the other brands, you have to look at the active ingredient list. if they list other stuff like benzo-, benzene, salicylate then don't get those.
(btw, i am a recent pharmacy graduate...just studying for board exams and becoming addicted to specktra when i procrastinate from my studies....but if you want a 2nd opinion, ask your local pharmacist for a recommendation)
hope that helps.