Photocontact allergy to benzocaine

A photodermatitis developed in two patients after the use of commercial sunscreens and a topical anesthetic lotion containing benzocaine. Photopatch testing indicated the presence of photocontact allergy to benzocaine. One patient had a positive photopatch test to a commercial glyceryl para-aminobenzoic acid (PABA) preparation that was heavily contaminated with benzocaine, but not to a benzocaine-free sample of glyceryl PABA. Benzocaine failed to produce phototoxic reactions in normal volunteers. Efforts to induce photocontact allergy in guinea pigs were unsuccessful.