British Journal of Dermatology 2001; 145: 597±601. Photoallergic contact dermatitis is uncommon

Summary Background Despite the enormous increase in sunscreen use, allergic contact (AC) and photoallergic (PA) reactions to ultraviolet (UV) filters are considered rare. Objectives To analyse the data from 2715 patients who underwent photopatch testing at St John's Institute of Dermatology during the period 1983±98. Methods A retrospective analysis of all positive photopatch test episodes was undertaken with the results retrieved from the environmental dermatology database and further verified with the original archived patch test documentation for each individual patient. Results In 111 patients with positive reactions (4´1%), there were 155 AC or PA reactions to allergens in the photopatch test series. Eighty PA reactions were observed in 62 (2´3%) patients (32 men and 30 women, age range 28±75 years), with UV filters accounting for 52 positive reactions (65%), drugs 16 (20%), musk ambrette 11 (14%) and the antiseptic trichlorocarbanilide one (1%). The most common UV filter photoallergen was benzophenone-3 with 14 positive results, followed by benzophenone-10 (n 9), isopropyl dibenzoylmethane (n 6), p-aminobenzoic acid (PABA) (n 5), octyl dimethyl PABA (n 5), butyl methoxydibenzoylmethane (n 4), isoamyl methoxycinnamate (n 2), ethyl methoxycinnamate (n 2), octyl methoxycinnamate (n 2)