Contact and photocontact sensitivity to sunscreens. Review of a 15-year experience and of the literature.

Abstract

This review summarizes published and unpublished data of our 15-year experience with sunscreen allergy and photoallergy. From 1981-1996, 402 patients with suspected clinical photosensitivity were patch and photopatch tested with the commercial sunscreens and facial cosmetics that they had used and with chemical UV absorbers, fragrance materials, preservatives, and emollients. 80 patients (20%) (28 men, 52 women) demonstrated allergic and/or photoallergic contact dermatitis to 1 or more UV absorber(s). In 47 patients with photodermatoses or photo-aggravated dermatoses and in 33 subjects with normal photosensitivity, 91 allergic and 84 photoallergic reactions to UV filters were observed. Over the years sunscreens were added to the test series, which since 1989 comprised the following 10 UV absorbers and which induced allergic (a) and photoallergic (pa) reactions (number, type of reaction): 4 UVA absorbers--isopropyldibenzoylmethane (30a/32pa); butyl methoxydibenzoyl-methane (15a/13pa); benzophenone-3 (3a/9pa); benzophenone-4 (0a/0pa); and 6 UVB absorbers--PABA (2a/2pa); octyl dimethyl PABA (1a/2pa); methylbenzylidene camphor (32a/5pa); octyl methoxycinnamate (3a/4pa); isoamyl p-methoxycinnamate (4a/10pa); and phenylbenzimidazole sulfonic acid (1a/7pa). The frequent (photo)sensitization to isopropyldibenzoylmethane was the reason that its production was discontinued in 1993. 47 patients reacted to fragrance materials, 11 to preservatives and 2 to lanolin alcohol. These constituents were contained in the commercial sunscreens and cosmetics that they had used. Continuous revision of the UV absorber photopatch test series was necessary to be closer to the real frequency of exposure and of reported (photo)allergy to newer sunscreens. Clinicians should consider contact and photocontact allergy, especially in patients with photodermatoses and photo-aggravated dermatoses, and they should perform photopatch testing. Once the culprit has been identified, its INCI (International Nomenclature Cosmetic Ingredients) designation should be given to the patient, who must be warned to avoid products containing the (photo)allergen.