No 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This review summarizes published and unpublished data of our 15-year experience with sunscreen allergy and photoallergy.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.

Solar urticaria serves as a model to illustrate the photodiagnostic approach in rare photodermatoses and to demonstrate how patients can be effectively helped by prophylactic and therapeutic intervention. To accomplish these tasks, advanced knowledge and experience in photodermatology is required, along with equipment which is often available in specialized centers only. A list is attached listing the dermatology departments with photodiagnostic units in Germany, Austria, and Switzerland.

The hedgehog is an in Germany previously unrecognized source of human ringworm. Eight hedgehog caretakers from Göttingen and the surrounding area developed dermatophytosis caused by Trichophyton erinacei. Four patients who handled the animals without gloves developed lesions on the hands that were more in keeping with hand eczema, leading to a delay in diagnosis. The other caretakers who wore gloves presented with typical ringworm on the arms, the big toe, the back, the abdomen, and the thighs. Their typical clinical features led to an early diagnosis and treatment.

Many artificial or naturally occurring substances are included under the term photosensitizer. After ultraviolet (UV) exposure such agents can lead to increased photosensitivity and subsequently to phototoxic or photoallergic reactions in the skin. From clinical observations and comprehensive studies typical reaction patterns can be deduced which can clarify the difference between phototoxic and photoallergic dermatitis.An illuminated epicutaneous test based on conventional epicutaneous tests, the photopatch test, was developed as a screening method for identification of photosensitizers. The diagnostic specificity and sensitivity of the test is comparable to conventional epicutaneous testing. If possible photosensitizers do not cause any relevant reactions with the photopatch test, other test procedures, such as the photoprick, photoscratch and illuminated intracutaneous tests are available. If the actual photosensitizer is not the test substance but a metabolite of the test substance, a systemic photoprovocation test can be indicated.