Contact and photocontact allergy to oxybenzone and mexenone

Benzophenones are a group of UV-A and UV-B absorbers that have been used in industry for several decades to protect textiles and paints from discoloration from sunlight exposure (1). The well-known sensitization and photosensitization properties of para-aminobenzoic acid (PABA) and its esters have led to a switch to PABA-free suncreens, initially considered as safer (2, 3). Benzophenones have become an accepted alternative. 4 of the 12 existing benzophenones are frequently incorporated into cosmetic and sunscreen formulations. Nowadays, oxybenzone (2-hydroxy-4-methoxybenzophenone; benzophenone-3; Eusolex® 4360) is by far the most frequently used agent in sunscreens with a sun protection factor (SPF) greater than 8.