I hope I don't sound paranoid but just always wondered. If in a couple somebody eats gluten cross-contaminated food and kisses the other person, and the other person has celiac like sensitivity to gluten would that cause a response?
Seriously, yes, if the person is very sensitive. I know a boy who is so intolerant to gluten that he had his full range of symptoms come on just from shaking someone's hand who'd just been kneading dough, and hadn't yet washed his hands. My daughter is very sensitive, and I don't allow gluten in my house, but she's around it in the world, of course.
It can happen with people with severe peanut allergies. There have been stories of young couples, where one of them had remnants of peanuts in their teeth and kissed their SO, resulting in SO going into anaphylactic shock.
I'm celiac, and this has been an issue for me in the past. It depends on your level of sensitivity, honestly, but in my opinion not worth the risk. If the person wants to kiss you that much, have them rinse their mouth and lips first. Believe me, it's better in the long run.
Or, you know, find a paleo mate :-)
Can be very serious, for those who are most sensitive. Here's a good blog post on the subject.
I've often heard in the allergy community brushing teeth is not good enough; it takes many hours (up to 8) for the allergen to go away.