hi you just need to think back it must be something you have opened using thumbs and forefingers logically these you would open something with could be a chemical fertiliser or something else that's given you this reaction. see your doctor and take it from there. good luck
i have a red rash with red bumps on the backs of my hands mostly clustered around the base of my thumb and forefinger. . i can't think of anything new i've come into contact with that i would be allergic to. a few of the larger bumps are almost look like small scrapes but they're not. they don't particularly hurt or itch. i've had them for about a week. i was sick with a bad cold recently. they don't seem to be spreading but they also don't seem to be getting better. they're contained to my hands as far as i can tell.