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Photoallergic Reactions (photoallergic + reaction)
Selected AbstractsPositive photocontact responses are not elicited to sunscreen ingredients exposed to UVA prior to application onto the skinCONTACT DERMATITIS, Issue 4 2007Shyamal Wahie Photocontact allergic reactions to sunscreen chemicals are investigated by photopatch testing. It has generally been assumed that for photocontact allergy to be shown, the putative pro-allergen must be in the skin at the time of ultraviolet A (UVA) exposure. However, this assumption has not, to our knowledge, been tested. The objective of this study was to determine whether positive photocontact responses can still be elicited when sunscreen chemicals are exposed to UVA prior to application onto the skin. 3 patients known to have positive photocontact reactions to a total of 6 sunscreen chemicals were studied. For conventional photopatch testing, patch test strips were applied onto the back and removed 1 D later, and the area was irradiated with UVA (5 J/cm2). For pre-irradiated testing, patches were exposed to the same dose of UVA immediately before application onto the back and then removed 1 D later. Skin responses were visually assessed by a blinded investigator 1 and 2 D after patch test removal. The same photocontact responses of the same magnitude, as previously documented for each patient, were seen at each of the conventional UVA-exposed patch test sites. However, in no patient was a positive response elicited at any of the sites where pre-irradiated patches had been applied. This study shows that positive photocontact responses to sunscreen chemicals do not occur when the putative pro-allergen is irradiated prior to application onto the skin. This suggests that for a photoallergic reaction to occur, the sunscreen chemical needs to be within the skin when activated by UVA. [source] Photopatch testing , a retrospective review using the 1 day and 2 day irradiation protocolsCONTACT DERMATITIS, Issue 2 2006R. J. Batchelor Photopatch testing is indicated in the investigation of patients with eczematous eruptions, affecting mainly light-exposed sites and in those who give a history of worsening of their condition with sun exposure. 3 different protocols are described by the British Photodermatology Group (Br J Dermatol 1997:136:371,376), 1 of which includes irradiation of allergens 1 day after application and 2 using irradiation of allergens 2 days after application. There is no evidence for superiority of any of these protocols. We reviewed the records of all patients who underwent photopatch testing in Leeds over a 50-month period, who had had the allergens applied in triplicate with 1 set irradiated after 1 day occlusion and another after 2 days. The control was occluded for 2 days. Readings were performed at 2 days and 4 days. 15 of 74 patients photopatch tested during this period had 49 positive results between them. 43 of these were felt to be of current relevance to their clinical problem. 34 of the positive results were indicative of photoallergy. Additional photoallergic reactions were detected following 2 days occlusion and irradiation compared with 1 day occlusion (16 versus 5). In conclusion, our case series suggests that 2 days occlusion before irradiation of allergens is more sensitive at detecting photoallergy. [source] Photoallergic contact dermatitis caused by ultraviolet filters in different sunscreensINTERNATIONAL JOURNAL OF DERMATOLOGY, Issue 2008Esther J. H. Collaris MD Over the last decade, a change in the public awareness regarding the possible danger of excessive sunlight exposure has resulted in an increased consumption of sunscreens. These products contain a broad spectrum of putative sensitizers that can cause contact dermatitis and, upon exposure to ultraviolet (UV) irradiation, photocontact dermatitis. Among these sensitizing compounds, UV filters are the most frequent cause of photoallergic reactions. Although rarely observed, we here describe the occurrence of a photoallergic contact dermatitis in a 55-year-old man after the use of two different sunscreens. Photopatch testing showed hypersensitivity reactions of the delayed type against three different chemical UV filters, 4-tert-butyl-4- methoxy-dibenzoylmethane (Parsol 1789), 2-ethylhexyl-p-methoxycinnamate (Parsol MCX), and isoamyl-p-methoxycinnamate (Neoheliopan). [source] A11. UV-related skin hazards: allergic photodermatitisJOURNAL OF COSMETIC DERMATOLOGY, Issue 2 2002Paolo Pigatto Cases of dermatitis induced by exposure to ultra-violet radiation are increasingly encountered in clinical practice, with contact allergic photodermatitis accounting for about 10% of cases. Its frequency seems to be increasing, not only as a result of the increased use of cosmetic products and contact with some of the materials of working processes, but above all because of the greater exposure to both natural and artificial sources of UV radiation. Many substances have been defined ,photo-allergising' but their exact prevalence has varied over the years with the introduction and use of new substances in cosmetics and pharmaceutical products. For these, and other reasons, there are few studies concerning the prevalence and incidence of contact allergic photodermatitis in Italy. A total of 2160 patients with clinical histories suggestive of photoallergic contact dermatitis were seen. All patients underwent photopatch tests with haptens proposed by the Gruppo Italiano Ricerca Dermatiti da Contatto plus other substances suggested by each patient's history. 518 patients (24%) were positive to at least one test substance of the standard series or to added substances. Typical photoallergic reactions were seen in 423 subjects, representing 19.5% of the total population. Topical drugs are the substances most frequently involved in photodermatitis. The incidence in our population was about equal for antimicrobial agents, additives to fragrances, and fragrances themselves. Other allergens frequently found were sun screening agents which were the second group of haptens with clear-cut relevance. [source] Photoallergic contact dermatitis to Heracleum giganteumPHOTODERMATOLOGY, PHOTOIMMUNOLOGY & PHOTOMEDICINE, Issue 2 2008Daniela Karimian-Teherani Summary Heracleum plants occur in numerous species worldwide and may cause phototoxic reactions due to its content of various furocoumarins. In this case report, a widespread photoallergic contact dermatitis after exposure to Heracleum giganteum (giant bear claw) is described. A photopatch test with extracts from the stem, leaves and seeds of the giant bear claw revealed a positive papulovesicular reaction that already appeared at 24 h and peaked at 72 h after irradiation with 5 J/cm2 UVA. The unirradiated controls remained negative. We conclude that in rare cases Heracleum plants may cause severe photoallergic reactions that can be verified by photopatch testing. [source] | ||||||||||