Sunscreen dermatitis due to glyceryl PABA: significance of cross-reactions to this PABA Ester

Glyceryl PABA (Escalol 106), present in many popular sunscreens, is a common sensitizer which invariably cross-reacts with benzocaine; it is present in over 400 over-the-counter products. Glyceryl PABA does not appear to cross-react with the sunscreening agents amyl (Escalol 506) and octyl (Escalol 507) dimethyl PABA. Glyceryl PABA, may, on occasion, cross-react with para-aminobenzoic acid (PABA), paraphenylenediamine, aniline, and sulfa drugs. Ironically, the sunscreening agent glyceryl PABA may, itself, act as a photosensitizing agent.