Toothpaste allergy?

I am curious if anyone else has had this problem. Any time I use a baking soda toothpaste, the corners of my lips get very chapped, dry, and painful, even if I only use it once or twice. After a lot of trial and error, I am pretty sure its the toothpaste causing it and not a lipstick or something like that. Has anyone heard of this before?





This is more a curiosity, since if I avoid that brand I am fine, but I think it is so weird.

Toothpaste allergy?
I had a problem like that with soap. The doctor told me to use Ivory. I havent out grown it either. Whenever I fo to a place without Ivory soap I breakout.