Photopatch tests: an Italian multicentre study from 2004 to 2006

Background:  Evaluation of possible photoallergic contact dermatitis in at-risk populations is often not undertaken, and an agreed methodology for investigation is uncommonly used.
Objectives:  We conducted a retrospective multicentre study to determine the prevalence of photoallergic contact dermatitis in Italy.
Methods:  A total of 1082 patients with histories and clinical features suggestive of photoallergic contact dermatitis were evaluated. All the patients had undergone photopatch testing with allergens proposed for Italy as well as other substances suggested by each patient's personal history.
Results:  234 patients (21.6%) were positive to at least one test substance of the standard photopatch testing series or to added substances. 234 patients (21.6%) were positive to at least one substance with a total of 290 reactions. 204 of the reactions were typically photoallergic; 68 reactions were allergic and within this group 10 were photoaugmented reactions; 18 reactions were considered to be phototoxic.
Conclusion:  The predominant group of photoallergens was drugs, followed by organic UV filters and antimicrobial agents.     

A double‐blind,randomized assessment of the irritant potential of sunscreen chemical dilutions used in photopatch testing*

Background: The maximum concentration of organic sunscreen filters in current usage that does not lead to irritant reactions when performing photopatch testing is not known. Such irritant reactions can be misinterpreted as positive photoallergic contact dermatitis reactions. Objective: To determine the frequency of irritant reactions to 19 organic sunscreen filters in current use. Patients/Methods: Ninety‐four healthy volunteers were photopatch tested using the European consensus methodology to three different concentrations (2%, 5%, and 10%) of 19 organic sunscreen filters at the Photobiology Unit in Dundee, UK. Results: Of the 94 subjects recruited, 80 were analysed after withdrawals and exclusions. Of the 19 organic sunscreen filters studied, only 2 compounds led to irritant reactions in ≥5% subjects. Five per cent and 10% benzophenone‐4 led to irritant reactions in four and six subjects, respectively. Five per cent methylene bis‐benzotriazolyl tetramethylbutylphenol led to irritant reactions in six subjects, but unlike benzophenone‐4, this was not in a dose‐dependent fashion. Conclusions: When performing photopatch testing according to the European consensus methodology with these 19 organic sunscreen filters, a 10% concentration is suitable for all filters, except benzophenone‐4, which should be tested at a concentration of 2%.     

Photopatch testing with an extended series of photoallergens: a 5-year study

Objective:  We conducted a retrospective study (2003–07) evaluating the results of photopatch tests (PPTs) performed with an extended series with the objective of determining the main photoallergens in our region and whether they would be detected by a recently recommended baseline PPT series.
Materials and methods:  83 patients (58 females/25 males, mean age 54.8 years) were tested with a photoallergen series, and among these, 30 were also tested with a non-steroidal anti-inflammatory drug (NSAID) series, irradiated at D2 with 5 J/cm² ultraviolet A (UVA).
Results:  Thirty-six of 83 patients (43.3%) had at least one positive reaction, with 21 (25.3%) reacting in the photoallergen series. The main relevant reactions were as follows: 10 to ultraviolet filters (benzophenone-3 and benzophenone-4, 3 patients each), 7 to promethazine, and 2 to chlorpromazine. Twenty of 30 patients tested (70%) had a relevant positive PPT to an NSAID, 9 to piroxicam because of systemic photosensitivity, 8 to benzydamine from a topical gel or oral solution, and 2 to ketoprofen.
Conclusions:  Our results are discordant with most recently published studies because of the particularities of the population studied and to regional prescribing habits. Therefore, apart from the recommended baseline series of photoallergens, other substances must be tested according to regional peculiarities.     

Photopatch testing: recommendations for a European photopatch test baseline series

In order to establish a consensus recommendation for performing photopatch testing, a photopatch test taskforce group was established under the joint umbrella of the European Society for Contact Dermatitis and the European Society for Photodermatology in 2000. After proposing the most adequate methodology in 2004 and completing a European multicentre photopatch test study in 2011, this taskforce is recommending a list of photoallergens that should form part of a baseline series for photopatch testing in Europe. It contains mainly ultraviolet filters and drugs, mostly non‐steroidal anti‐inflammatory drugs. The choice of chemicals was based on the results of a recent multicentre study, previous published cases of photoallergy, and use of the substances in the European market. It is suggested that an extended list of photoallergens should be photopatch tested in selected cases, along with patients' own products. Two contact allergens, cinnamyl alcohol and decyl glucoside, should be simultaneously patch tested in order to clarify photopatch and patch test reactions, respectively, to ketoprofen and methylene bis‐benzotriazolyl tetramethylbutylphenol (Tinosorb M?).     

Photosensitivity: the 9-year experience at a Sydney contact dermatitis clinic

In this retrospective study, 81 patients with photosensitivity were referred to the Contact and Occupational Dermatitis Clinic at The Skin and Cancer Foundation Australia, in Sydney, between 1991 and 1999. Photoallergic contact dermatitis (PACD) was diagnosed in 39.5% of patients, with 87.5% of these reactions being to sunscreen chemicals. Polymorphic light eruption (PMLE) accounted for 19.7% of cases, drug photosensitivity 14.8%, and photoaggravated atopic dermatitis and chronic actinic dermatitis (CAD) each constituted 7.4%. Compared with overseas studies, there was a high incidence of PACD, possibly reflecting the referral bias and widespread use of sunscreens. The incidence of PMLE and CAD was less than studies from cooler climates overseas. No cause could be determined for three photosensitive patients.     

Photoallergic contact dermatitis

Background: Photoallergic contact dermatitis (PACD) presents in patients after certain exogenous agents come into contact with the skin in the presence of ultraviolet and/or visible light. The best method currently available for investigating PACD is photopatch testing. However, photopatch testing as an investigation is under‐used by clinicians, and therefore PACD may go undetected in many patients. Purpose: To highlight the importance of PACD and photopatch testing when investigating patients with a photo‐exposed site dermatosis. Method: A comprehensive review of the available literature relating to PACD and photopatch testing. Results: Experimental evidence suggests that PACD is a delayed type hypersensitivity reaction. Various agents have been historically shown to cause PACD, but currently the most common photosensitizers are sunscreens and topical non‐steroidal anti‐inflammatory drugs. Photopatch testing has in the past been subject to differing methodologies; however, a European consensus methodology now exists and should allow a greater comparison of results across centres. As chemical, pharmaceutical, and cosmetic industries produce new agents, photopatch testing of such agents in humans before release in the marketplace may prevent widespread contact with potent photosensitizers. It will also be important for ongoing multi‐centre studies of existing agents to be conducted in order to keep the photopatch test batteries used by clinicians investigating PACD up to date.     

Photopatch testing: a consensus methodology for Europe

A group of interested European Contact Dermatologists/Photobiologists met to produce a consensus statement on methodology, test materials and interpretation of photopatch testing. While it is recognized that a range of local variables operate throughout Europe, the underlying purpose of the work is to act as an essential preamble to a Pan European Photopatch Test Study focusing particularly on sunscreen chemicals.     

51例面部化妆品接触性皮炎的斑贴试验和光斑贴试验结果分析

目的:检测分析面部化妆品接触性皮炎患者常见致敏原。方法:回顾性分析我院面部化妆品接触性皮炎患者的临床资料、斑贴试验和光斑贴试验资料。结果:51例患者进行了斑贴试验,总体阳性率为96%。阳性率高的过敏源依次为：硫酸镍(47.1%)、氯化钴(35.3%)、甲基异噻唑啉酮(27.5%)、纺织染料混合物(19.6%)、没食子酸辛酯(19.6%)、松香(13.7%)、对苯二胺(13.7%)、硫柳汞(13.7%)、叔丁基氢醌(13.7%)、棓酸十二烷酯(13.7%)。46例患者完成光敏实验和光斑贴检查,14例存在光敏感(30.43%);其中UVA敏感7例(15.22%),UVB敏感8例(17.39%)。光斑贴阳性率19.6%,常见致敏原依次为：依托酚那酯(6.5%)、癸基葡糖苷(6.5%)、甲酚曲唑三硅氧烷(4.3%)。结论:防腐剂、香料、重金属、乳化剂、抗氧化剂、表面活化剂等原料均可能引起面部接触致敏。面部化妆品皮炎患者还可能存在光敏反应和光变态反应。全面的斑贴试验有助于更好的帮助患者查找致敏原。     

7 years experience of photopatch testing with sunscreen allergens in Sweden

Since 1990 7 sunscreen allergens have been included in the standard photopatch protocol at 2 Swedish dermatology clinics. 355 consecutive patients with suspected photosensitivity were tested, and in 28 of these (7.9%), a total of 42 allergic reactions were found. 80% of the reactions were of photocontact origin. The most common allergen was benzophenone-3 (Eusolex 4360), with 15 photocontact and 1 contact allergic reactions, followed by isopropyl dibenzoylmethane (Eusolex 8020) (8 photocontact, 4 contact) and butyl methoxydibenzoylmethane (Parsol 1789), with 6 photocontact reactions. There were 2 cases of photocontact allergy to phenylbenzimidazole sul-fonic acid (Eusolex 232), which has not been reported previously. 1 case of contact urticaria from benzophenone-3 was accidentally found. In addition, 21 p reactions of doubtful relevance were noted in 14 patients: 16 on irradiated and 5 on non-irradiated test sites. Among these, irritant and phototoxic reactions may be included. These results indicate that the inclusion of UV filters in the standard photopatch protocol is important. Immediate-type testing for urticaria could also be of value.     

Results of photopatch testing in Rotterdam during a 10-year period

BACKGROUND: Photoallergic contact dermatitis is of importance in a proportion of photodermatoses and can be evaluated through photopatch testing. OBJECTIVES: To conduct a retrospective evaluation of photopatch tests performed in patients with suspected photodermatoses at the clinic at the University Hospital Rotterdam during a 10-year period. METHODS: During the first 5(1/2) years 44 patients were tested with a standard set of 14 allergens, and during the next 4(1/2) years 55 patients were tested with a standard set of 23 allergens. RESULTS: Photocontact reactions were found in 9% and 27% of patients in the two periods, respectively. In the second period, positive reactions were mostly produced by sunscreens. The difference in the percentage of positive photopatch tests was probably caused by the difference in composition of the standard set of allergens (more sunscreens in the second period), this being the only alteration in the test procedure. CONCLUSIONS: The standard set of photoallergens has to be updated periodically. Standardization of the test procedure is needed to compare the test results of different institutions.     

Patch testing in discoid eczema

We report a retrospective study of patch testing in patients with discoid eczema. 48 patients with persistent or severe discoid eczema were patch tested. The mean age of patients was 45 years and the median duration of symptoms was 6 months. 24 patients (50%) had positive patch tests, and 16 of these (33%) were considered to be clinically relevant. The most common allergens implicated were rubber chemicals, formaldehyde, neomycin, chrome, nickel (5, 2, 2, 2, 2, 2 reactions, respectively). 13 of 16 patients were followed up by telephone in 1996, and 8/13 (61%) slated they had benefited from patch testing. This study suggests allergic contact dermatitis is relatively common in persistent discoid eczema, and allergen avoidance may be of benefit. We recommend patch testing should be considered for all patients with severe or persistent discoid eczema.