Tongue erosions and diet cola.

We report the case of a 38-year-old woman who presented with a 10-year history of painful ulcerations on her tongue. She reported that she drank large quantities of diet cola and some orange juice daily and that she used cinnamon-flavored toothpaste and mouthwash nightly. Patch testing elicited positive reactions to balsam of Peru (a fragrance as well as a flavoring agent put in cola drinks that cross-reacts with orange juice) and cinnamic aldehyde. She was diagnosed with allergic contact dermatitis. She was put on a restricted diet and a fragrance-free regimen, and her condition resolved.