I figured I would share this, since I'm sure I'm not the only one who's been in this situation.
I've had eczema on my hands and feet since I was a tot myself, and I'm pretty sure I got it from my dad. My DD now gets contact dermatitis when she eats acidic foods, usually sauces. (Ketchup, dressing, tomato sauce, OJ, etc.) For those of you who are wondering what this is: on the occasion we are unable to wipe DD's face quickly when she gets stuff all over it (i.e. she's still eating,) when we finally do wipe it off, the skin underneath is bright red like sunburn and splotchy like camoflage. So far, nothing has been scarier than being in this situation and realizing we have no benadryl or cortizone cream in the house. My advice: keep both in the house at all times, just in case, especially if someone in your family has a food allergy.