The present guideline summarizes all aspects of patch testing for the diagnosis of contact allergy in patients suspected of suffering, or having been suffering, from allergic contact dermatitis or other delayed-type hypersensitivity skin and mucosal conditions. Sections with brief descriptions and discussions of different pertinent topics are followed by a highlighted short practical recommendation. Topics comprise, after an introduction with important definitions, materials, technique, modifications of epicutaneous testing, individual factors influencing the patch test outcome or necessitating special considerations, children, patients with occupational contact dermatitis and drug eruptions as special groups, patch testing of materials brought in by the patient, adverse effects of patch testing, and the final evaluation and patient counselling based on this judgement. Finally, short reference is made to aspects of (continuing) medical education and to electronic collection of data for epidemiological surveillance.

Background While photopatch testing is recognized as the investigation of choice for photoallergic contact dermatitis, changes in potential photoallergen exposure and variables within the photopatch test technique have led to challenges in its usage within dermatology.Objectives The main objectives of this study were to determine the nature and prevalence of topical photoallergens in Europe and to investigate the variable of photoallergen occlusion time before irradiation on photopatch testing outcomes.Methods A prospective multicentre study of photopatch testing to sunscreens, nonsteroidal anti-inflammatory drugs (NSAIDs) and other agents was conducted in 10 centres across seven European countries. A within-participant comparison of a 24-h and 48-h occlusion period prior to irradiation was included in the study design, to investigate the effect of this variable on photopatch testing outcomes.Results Of study participants, 28 photoallergic reactions were seen, with 10% (13 of 132) of participants reacting to sunscreen chemicals and 9% (9 of 101) to NSAIDs. The most prevalent photoallergens were ketoprofen (n = 6), promethazine (n = 4), butylmethoxydibenzoylmethane (avobenzone/parsol 1789) (n = 4), benzophenone-3 (oxybenzone) (n = 3) and etofenamate (n = 3). Contact allergies were less frequent (14 reactions). When a 24-h occlusion was used prior to irradiation, 53% of sunscreen photoallergic reactions and 36% of NSAID reactions were missed compared with the 48-h occlusion. Most participants had a history of photoexposed site dermatitis or sunscreen/NSAID reaction or had a photosensitivity disease, and 49% of participants had a history of dermatological conditions. All indications for photopatch testing were represented in those with positive photopatch tests, with no specific indicator of those most at risk.Conclusions Photopatch testing remains an essential investigation for people with suspected photocontact allergies. Based on these study findings, the nature of topical photoallergens appears to be stable, but vigilance and ongoing review are required. To optimize the pick-up rate of photoallergy, we recommend a 48-h occlusion period prior to irradiation, if practicable. Photoallergic contact dermatitis occurs when certain substances on the skin react with sunlight and cause a rash. To diagnose this skin condition, a method called photopatch testing can be used. Photopatch testing is considered the best way to diagnose photoallergic contact dermatitis. However, there have been changes in the types of chemicals people are exposed to. There are also differences in how the test is done. This makes it harder for doctors to use it confidently.This study was carried out by researchers from 10 medical centres in 7 European countries. The aim was to investigate the photopatch testing method. We tested study participants using products like sunscreens, non-steroidal anti-inflammatory drugs (NSAIDs), and other substances known to cause photoallergic reactions. We also wanted to see whether the time the test patches stayed on the skin before light exposure (either 24 h or 48 h) affected the test results. We found that photoallergic reactions were fairly common. In total, 10% of participants reacted to sunscreen chemicals, and 9% reacted to NSAIDs. The most frequent problem substances were ketoprofen, promethazine, avobenzone, oxybenzone and etofenamate. Contact allergies unrelated to light were less common. We also found that using 24 h of skin contact before light exposure missed many reactions. This applied to over half of the sunscreen-related reactions and more than one-third of the NSAID reactions. This finding suggests that a 48-h occlusion time makes the test more accurate.Overall, our study results suggest that photopatch testing is an important investigation. The types of substances causing reactions seem stable, but doctors should remain alert. When possible, using a 48-h skin contact period is recommended. Photopatch testing is used to investigate photoallergic contact dermatitis but variables in the technique have led to challenges in its use. We investigated the nature of topical photoallergens and the effect of photoallergen occlusion time on photopatch testing outcomes in a prospective study in seven European countries. Topical sunscreen and nonsteroidal anti-inflammatory drugs (NSAIDs) photoallergy was seen in 10% and 9% of participants respectively. The main photoallergens were ketoprofen, promethazine, avobenzone, oxybenzone and etofenamate. Photoallergy to sunscreens and NSAIDs would be missed in 53% and 36%, respectively, if a 24-h photoallergen occlusion period was used rather than 48 h. We highlight the importance of photopatch testing and of considering the use of a 48-h photoallergen occlusion period.

BACKGROUND:Whilst photopatch testing is recognized as the investigation of choice for photoallergic contact dermatitis, changes in potential photoallergen exposure and variables within the photopatch test technique, have led to challenges in its usage within dermatology. OBJECTIVES:The main objectives of this study were to determine the nature and prevalence of topical photoallergens in Europe and investigate the variable of photoallergen occlusion time before irradiation, on photopatch testing outcomes. METHODS:A prospective multi-centre study of photopatch testing to sunscreens, non-steroidal anti-inflammatory drugs (NSAIDs) and other agents was conducted in 10 centres across seven European countries. A within-subject comparison of a 24h and 48h occlusion period prior to irradiation was included in the study design, to investigate the effect of this variable on photopatch testing outcomes. RESULTS:Of study participants, 28 photoallergic reactions were seen, with 10% (13/132) of participants reacting to sunscreen chemicals and 9% (9/101) to NSAIDs. The most prevalent photoallergens were ketoprofen (n=6), promethazine (n=4); butylmethoxydibenzoylmethane (Avobenzone/Parsol 1789) (n=4), benzophenone-3 (oxybenzone) (n=3) and etofenamate (n=3). Contact allergies were less frequent (14 reactions). When a 24h occlusion was used prior to irradiation, 53% of sunscreen photoallergic reactions and 36% of NSAID reactions were missed compared with the 48h occlusion. Most participants had a history of photo-exposed site dermatitis or sunscreen/NSAID reaction or had a photosensitivity disease, and 49% of participants had a history of dermatological conditions. All indications for photopatch testing were represented in those with positive photopatch tests, with no specific indicator of those most at risk. CONCLUSIONS:Photopatch testing remains an essential investigation for people with suspected photocontact allergies. Based on these study findings, the nature of topical photoallergens appears stable, but vigilance and ongoing review are required. To optimise the pick-up rate of photoallergy, we recommend, if practicable, a 48h occlusion period prior to irradiation.(Clinicaltrials.gov - NCT03812887).

BACKGROUND:Allergic contact dermatitis (ACD) is an increasingly recognised condition in children and adolescents. However, there is limited knowledge about the different paediatric patch test procedures in European patch test clinics. OBJECTIVES:To map current European paediatric patch test practices, and to relate these to the existing literature, with the aim of guiding the development of a future paediatric patch test guideline, and a corresponding paediatric European baseline series (pEBS). MATERIALS AND METHODS:In the course of late 2023/early 2024, a standardised paediatric patch test e-mail questionnaire was developed, distributed, and discussed among members of the European Baseline Series (EBS) Working Party of the European Society of Contact Dermatitis (ESCD). RESULTS:Areas of agreement and discussion were identified regarding patch testing in children of different ages, with and without atopic dermatitis: (contra)indications, choice of allergens and patch test chambers, peculiarities regarding the application and fixation of tests, occlusion and reading times. CONCLUSION:Although variability exists in paediatric patch test practices across Europe, there is broad agreement on common procedures, and only a few areas of debate; these findings may be used to inform the development of a future paediatric patch test guideline and pEBS.

We report the case of a 62-year-old man who developed a generalized eczematous dermatitis while scuba diving, which became apparent upon removing his wetsuit. Despite this initial reaction occurring 2 years prior, he continued to experience persistent, well-demarcated dermatitis around his waistband, along with intermittent patches on his trunk and limbs. He had a history of atopic eczema but no other significant medical conditions. His occupation was in film editing. Patch testing revealed positive reactions by 96 h to black rubber mix (0.6% in petrolatum) and N-isopropyl-N-phenyl phenylenediamine (IPPD) (0.1% in petrolatum) within the British Society for Cutaneous Allergy’s baseline series. Further positive reactions were noted to IPPD (0.25%) and cyclohexyl-N-phenyl-4-phenylenediamine (1%) in the rubber series. Additionally, he reacted to aminoazobenzene and Disperse Blue 35 in our textile series, dyes commonly found in synthetic fibre garments. Wetsuits are primarily composed of neoprene, a flexible, buoyant synthetic rubber. Thiourea-based rubber accelerators enhance the vulcanization process in neoprene-containing products and are known contact allergens. However, thiourea mix testing was negative in this patient. IPPD is a well-established screening allergen for black rubber. Black rubber mix, in use for patch testing since 1971, contains IPPD, N-cyclohexyl-N-phenyl-4-phenylenediamine, and N,N-diphenyl-4-para-phenylenediamine antioxidants, which also contribute to the material’s black–grey colour. Contact allergy to black rubber is most commonly associated with gloves and footwear, as well as vehicle tyres. While black rubber components are present in diving equipment, there have been no previous reports of allergic contact dermatitis from wetsuits. The patient was advised to contact wetsuit manufacturers to verify the absence of black rubber before purchasing a replacement. Given that elasticized clothing can contain hidden black rubber components woven into fabric, it was suspected that his persistent waistband dermatitis might have been exacerbated by elasticized or dyed synthetic fibres. He was therefore advised to opt for drawstring garments and avoid clothing containing Disperse Blue 35 (dark blue) and aminoazobenzene (yellow–orange) dyes. To our knowledge, this represents the first reported case of allergic contact dermatitis to black rubber mix components in a wetsuit.

BACKGROUND:The use of methylisothiazolinone (MI) as a preservative in cosmetic products caused an alarming increase in MI contact allergy across Europe in the 2010s. This was followed by regulations of use with a total ban on leave-on (implemented in 2017) and reduced use concentrations in rinse-off cosmetics (2018). OBJECTIVE:To follow-up on the prevalence of contact allergy to MI and the related benzisothiazolinone (BIT) and octylisothiazolinone (OIT) in consecutively patch-tested patients in Europe. METHODS:A cross-sectional audit following the design of two previous audits on MI contact allergy from 1 May 2022 to 31 October 2022 included all patients patch tested with the European baseline series, including or supplemented with MI, BIT and OIT across 10 departments in eight European countries. RESULTS:A total of 2554 patients were consecutively patch tested with the three isothiazolinones during the study period. The prevalence of MI and BIT contact allergy was 2.9% (95% confidence interval [CI]: 2.3%-3.7%; range 1.1%-5.8%) and 3.1% (95% CI: 2.4%-3.9%; range 0.0%-6.6%), respectively; that of OIT was 0.7% (95% CI: 0.4%-1.1%; range 0%-3.2%). Rinse-off cosmetic (73.3%) and leave-on cosmetic products (13.3%) were still associated with eliciting allergic contact dermatitis to MI. CONCLUSION:We confirmed a positive impact of regulatory measures on the prevalence of MI contact allergy in Europe, which halved compared to 2015. However, our data suggest that consumers may still be exposed to older cosmetic products containing MI. BIT has superseded MI in causing contact allergy, despite not being allowed for use in cosmetic products.

Use of medical devices (MDs), that is, glucose sensors and insulin pumps, in patients with Type 1 diabetes mellitus (T1D) has proven an enormous advantage for disease control. Adverse skin reactions from these MDs may however hamper compliance. The objective of this study was to systematically review and analyse studies assessing the prevalence and incidence of dermatitis, including allergic contact dermatitis (ACD) related to MDs used in patients with T1D and to compare referral routes and the clinical investigation routines between clinics being part of the European Environmental and Contact Dermatitis Research Group (EECDRG). A systematic search of PubMed, EMBASE, CINAHL and Cochrane databases of full-text studies reporting incidence and prevalence of dermatitis in persons with T1D using MDs was conducted until December 2021. The Newcastle-Ottawa Scale was used to assess study quality. The inventory performed at EECRDG clinics focused on referral routes, patient numbers and the diagnostic process. Among the 3145 screened abstracts, 39 studies fulfilled the inclusion criteria. Sixteen studies included data on children only, 14 studies were on adults and nine studies reported data on both children and adults. Participants were exposed to a broad range of devices. Skin reactions were rarely specified. It was found that both the diagnostic process and referral routes differ in different centres. Further data on the prevalence of skin reactions related to MDs in individuals with T1D is needed and particularly studies where the skin reactions are correctly diagnosed. A correct diagnosis is delayed or hampered by the fact that, at present, the actual substances within the MDs are not declared, are changed without notice and the commercially available test materials are not adequately updated. Within Europe, routines for referral should be made more standardized to improve the diagnostic procedure when investigating patients with possible ACD from MDs.

The diagnosis of eczema ('dermatitis') is mostly clinical and depends on the clinical history and exploratory objective findings (primary lesions, patterns). Contact dermatitis remains as an important condition in the group of eczematous disorders, with important socioeconomic and occupational relevance. Although irritant and allergic contact dermatitis have a different pathogenesis, both are characterized by a rather typical morphology, are triggered by external factors and tend to occur primarily in the area of contact with the exogenous agent. In addition, allergic and irritant dermatitis may also co-exist. The importance of diagnosing contact dermatitis, especially when allergic in nature, is both due to the possibility of avoiding the trigger, and due to its role in aggravating other skin conditions. Nevertheless, the heterogeneity of clinical presentations in daily practice may pose an important challenge for the suspicion and correct diagnosis of contact dermatitis. Furthermore, other conditions, with different pathogenesis and treatment, may clinically simulate contact dermatitis. The Task Force aims to conduct a review of the unifying clinical features of contact dermatitis and characterize its main clinical phenotypes, and its simulators, in order to contribute to an early suspicion or recognition of contact dermatitis and enable a correct differential diagnosis.

BACKGROUND:There is a current fashion for the use of methacrylate-containing nail cosmetics that can induce allergic contact dermatitis. European Union (EU) legislation was introduced in 2021 that had the aim of preventing its development. OBJECTIVES:To assess prevalence and exposures causing contact allergy to 2-hydroxyethyl methacrylate (HEMA) prior to and following implementation of the legislation. METHODS:A retrospective audit was conducted by 7 European centres patch testing to HEMA prior to the legislation and for 2 years afterwards. RESULTS:A total of 26 297 patients were tested to HEMA in the baseline series between 2016 and 2023. The prevalence of contact allergy to HEMA from all sources amongst females was 2.82% compared to 0.34% amongst males. The prevalence of nail related contact allergy rose from 0.91% in 2016 (2 centres) to: 0.99% in 2017 (3 centres); 1.24% in 2018 (5 centres); 1.23% in 2019 (6 centres); 1.36% in 2020 (7 centres); 1.30% in 2021 (7 centres); 1.52% in 2022 (7 centres) and 1.98% in 2023 (7 centres). Contact allergy to HEMA from exposure to nail cosmetics accounted for 3.4% of all occupational skin disease. CONCLUSIONS:EU legislation appears not to have had the intended impact on controlling allergic contact dermatitis from methacrylates in nail cosmetics. There is an urgent need to revisit Scientific Committee on Consumer Safety (SCCS) opinion to reconsider exposure to methacrylates and cross-reactions between them. A strategy needs to be developed and implemented to better control the current outbreak.

Patch testing is the only clinically applicable diagnostic method for Type IV allergy. The availability of Type IV patch test (PT) allergens in Europe, however, is currently scarce. This severely compromises adequate diagnostics of contact allergy, leading to serious consequences for the affected patients. Against this background, the European Society of Contact Dermatitis (ESCD) has created a task force (TF) (i) to explore the current availability of PT substances in different member states, (ii) to highlight some of the unique characteristics of Type IV vs. other allergens and (iii) to suggest ways forward to promote and ensure availability of high-quality patch testing substances for the diagnosis of Type IV allergies throughout Europe. The suggestions of the TF on how to improve the availability of PT allergens are supported by the ESCD, the European Academy of Allergy and Clinical Immunology, and the European Academy of Dermatology and Venereology and intend to provide potential means to resolve the present medical crisis.

BACKGROUND:Occupational skin diseases have led the occupational disease statistics in Europe for many years. Especially occupational allergic contact dermatitis is associated with a poor prognosis and low healing rates leading to an enormous burden for the affected individual and for society.OBJECTIVES:To present the sensitization frequencies to the most relevant allergens of the European baseline series in patients with occupational contact dermatitis (OCD) and to compare sensitization profiles of different occupations.METHODS:The data of 16 022 patients considered having OCD after patch testing within the European Surveillance System on Contact Allergies (ESSCA) network between January 2011 and December 2020 were evaluated. Patients (n = 46 652) in whom an occupational causation was refuted served as comparison group.RESULTS:The highest percentages of OCD were found among patients working in agriculture, fishery and related workers, metal industry, chemical industry, followed by building and construction industry, health care, food and service industry. Sensitizations to rubber chemicals (thiurams, carbamates, benzothiazoles) and epoxy resins were associated with at least a doubled risk of OCD. After a decline from 2014 onwards, the risks to acquire an occupation-related sensitization to methyl(chloro)isothiazolinone (MCI/MI) and especially to methylisothiazolinone (MI) seem to increase again. Sensitization rates to formaldehyde were stable, and to methyldibromo glutaronitrile (MDBGN) slightly decreasing over time.CONCLUSIONS:Among allergens in the European Baseline Series, occupational relevance is most frequently attributed to rubber accelerators, epoxy resins and preservatives.

Importance The common use of isothiazolinones as preservatives is a global cause of allergic contact dermatitis. Differences in allowable concentrations of methylisothiazolinone (MI) exist in Europe, Canada, and the US. Objective To compare the prevalence of positive patch test reactions to the methylchloroisothiazolinone/methylisothiazolinone (MCI/MI) combination and MI alone in North America and Europe from 2009 to 2018. Design, Setting, and Participants This retrospective analysis of North American Contact Dermatitis Group, European Surveillance System on Contact Allergies (ESSCA), and the Information Network of Departments of Dermatology (IVDK) databases included data from patients presenting for patch testing at referral patch test clinics in North America and Europe. Exposures Patch tests to MCI/MI and MI. Main Outcomes and Measures Prevalence of allergic contact dermatitis to MCI/MI and MI. Results From 2009 to 2018, participating sites in North America and Europe patch tested a total of 226 161 individuals to MCI/MI and 118 779 to MI. In Europe, positivity to MCI/MI peaked during 2013 and 2014 at 7.6% (ESSCA) and 5.4% (IVDK) before decreasing to 4.4% (ESSCA) and 3.2% (IVDK) during 2017 and 2018. Positive reactions to MI were 5.5% (ESSCA) and 3.4% (IVDK) during 2017 and 2018. In North America, the frequency of positivity to MCI/MI increased steadily through the study period, reaching 10.8% for MCI/MI during 2017 and 2018. Positive reactions to MI were 15.0% during 2017 and 2018. Conclusions and Relevance The study results suggest that in contrast to the continued increase in North America, isothiazolinone allergy is decreasing in Europe. This trend may coincide with earlier and more stringent government regulation of MI in Europe.

Allergic contact dermatitis due to isothiazolinone derivatives is frequently observed both in consumers and in occupational exposures. In this article, we will review contact dermatitis to the most commonly used isothiazolinones, including trends in rates of allergy globally based on legislative changes, as well as looking at clinical presentation, diagnostic, and future considerations. Isothiazolinone derivatives are ubiquitous in cosmetic, cleaning, and industrial products and are a significant cause of allergic contact dermatitis as highlighted by the epidemic of allergy seen with methylchloroisothiazolinone/methylisothiazolinone (MCI/MI) and methylisothiazolinone (MI) which peaked in 2013–2014 in the EU. Changes in EU cosmetic legislation have led to a reduction in cases of allergic contact dermatitis from MCI/MI and MI. However, there is a degree of variability in legislation regarding permitted use in Europe and internationally, with cases in the USA and Canada still remaining high. We are also seeing an emergence of cases from other isothiazolinones, particularly benzisothiazolinone (BIT), increasingly being used by the chemical industry, resulting in not only occupational contact allergy but also an issue for consumers using non-cosmetic products such as in paints, detergents, and glues. The clinical presentation is variable and often reflected by the exposure pattern and isothiazolinone involved based on its permitted use in that particular part of the world. Patch testing is the gold standard for diagnosing allergic contact dermatitis and although generally accepted patch test concentrations for the isothiazolinones have been detailed, the appropriate patch test concentrations for BIT and octylisothiazolinone (OIT) may still need to be established. Isothiazolinone contact dermatitis remains a significant issue despite legislative changes. Globally, a review of the regulations relating to use of these preservatives in cosmetic, detergent and industrial materials is required. Furthermore, issues with regard to accurate labelling and the presence of isothiazolinones in medical devices and the chemical industry require further legislation. There is a potential risk from newer and currently lesser known isothiazolinone derivatives causing contact allergy going forward.

Contact DermatitisVolume 88, Issue 6 p. 485-487 CONTACT POINT Contact allergy to resacetophenone Stephen Mark Wilkinson, Corresponding Author Stephen Mark Wilkinson [email protected] orcid.org/0000-0001-7253-3461 Dermatology, Chapel Allerton Hospital, Leeds Teaching Hospitals, Leeds, UK Correspondence Stephen Mark Wilkinson, Dermatology, Chapel Allerton Hospital, Leeds Teaching Hospitals, Leeds LS7 4SA, UK. Email: [email protected] Contribution: Writing - original draft, Writing - review & editing, ​InvestigationSearch for more papers by this author Stephen Mark Wilkinson, Corresponding Author Stephen Mark Wilkinson [email protected] orcid.org/0000-0001-7253-3461 Dermatology, Chapel Allerton Hospital, Leeds Teaching Hospitals, Leeds, UK Correspondence Stephen Mark Wilkinson, Dermatology, Chapel Allerton Hospital, Leeds Teaching Hospitals, Leeds LS7 4SA, UK. Email: [email protected] Contribution: Writing - original draft, Writing - review & editing, ​InvestigationSearch for more papers by this author First published: 20 February 2023 https://doi.org/10.1111/cod.14298Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL No abstract is available for this article. CONFLICT OF INTEREST STATEMENT The authors declare no conflict of interest. REFERENCES 1Pastor-Nieto MA, González-Muñoz P, Martín-Alcalde E, Gatica-Ortega ME. Allergic contact dermatitis from resacetophenone (2′,4′-dihydroxyacetophenone; CAS no. 89-84-9) in an antifungal nail preparation. Contact Dermatitis. 2022; 87(6): 539- 541. 2 National Center for Biotechnology Information. PubChem Compound Summary for CID 7410, Acetophenone. Accessed December 16, 2022. https://pubchem.ncbi.nlm.nih.gov/compound/Acetophenone 3 National Center for Biotechnology Information. PubChem Compound Summary for CID 10757, 2-Chloroacetophenone. Accessed December 16, 2022. https://pubchem.ncbi.nlm.nih.gov/compound/2-Chloroacetophenone 4Madden JF. Cutaneous hypersensitivity to tear gas (chloroacetophenone); a case report. AMA Arch Derm Syphilol. 1951; 63(1): 133- 134. 5Penneys NS, Israel RM, Indgin SM. Contact dermatitis due to 1-chloroacetophenone and chemical mace. N Engl J Med. 1969; 281(8): 413- 415. 6Fuchs T, in der Wiesche M. Contact allergies to CN and CS ("tear gas") in participants in demonstrations. Z Hautkr. 1990; 65(3): 288–92, 295. 7Jensen CD, Andersen KE. Allergic contact dermatitis from a paper mill slimicide containing 2-bromo-4′-hydroxyacetophenone. Am J Contact Dermat. 2003; 14(1): 41- 43. 8Boffa MJ, Heron RJ, Wilkinson SM, Beck MH. Allergic contact dermatitis from 3-(alpha-methoxy) methylenebenzofuran-2(3H)-one (MBF) and alpha-chloro-4-fluoroacetophenone (CFAP) in chemical process workers. Contact Dermatitis. 1996; 34(6): 434- 435. 9 National Center for Biotechnology Information. PubChem Compound Summary for CID 7469, 4'-Hydroxyacetophenone. Accessed December 16, 2022. https://pubchem.ncbi.nlm.nih.gov/compound/4_-Hydroxyacetophenone 10Sanz-Sánchez T, Valverde Garrido R, Maldonado Cid P, Díaz-Díaz RM. Allergic contact dermatitis caused by hydroxyacetophenone in a face cream. Contact Dermatitis. 2018; 78(2): 174- 175. 11Gatica-Ortega ME, Sanz-Sánchez T, Pastor-Nieto MA. Allergic contact dermatitis from hydroxyacetophenone in an anti-wrinkle facial serum with flare-up reactions triggered by the repeated open application test. Contact Dermatitis. 2023. doi:10.1111/cod.14284 12 National Center for Biotechnology Information. PubChem Compound Summary for CID 6990, 2',4'-Dihydroxyacetophenone. Accessed December 16, 2022. https://pubchem.ncbi.nlm.nih.gov/compound/2_4_-Dihydroxyacetophenone 13Raison-Peyron N, Bergendorff O, Bourrain JL, Bruze M. Acetophenone azine: a new allergen responsible for severe contact dermatitis from shin pads. Contact Dermatitis. 2016; 75(2): 106- 110. 14De Fré C, Bergendorff O, Raison-Peyron N, et al. Acetophenone azine: a new shoe allergen causing severe foot dermatitis. Contact Dermatitis. 2017; 77(6): 416- 417. 15Raison-Peyron N, Sasseville D. Acetophenone azine. Dermatitis. 2021; 32(1): 5- 9. 16Manière I, Aubert A, Dubois C, Solal C, Lepoittevin JP, Rousselle C. Sensitization properties of acetophenone azine, a new skin sensitizer identified in textile. Contact Dermatitis. 2023; 88(1): 35- 42. Volume88, Issue6June 2023Pages 485-487 ReferencesRelatedInformation

Shellac, the purified resin produced from the female lac bug (Kerria lacca), has its application within a wide range of industries, including healthcare, food, wood treatments and cosmetics. Shellac 20% alcohol is included in the British Society for Cutaneous Allergy/European Society of Contact Dermatitis extended facial series based on frequency of reactions exceeding the 0.3% threshold. However, the source of primary sensitization remains difficult to characterize through patch testing as relevance is not always clear and the test preparation has an irritant potential. We present a series of 28 patients from 2013 to 2022 with positive or irritant reactions to shellac, to elucidate its reaction pattern and relevance within our outpatient population. Cases with confirmed shellac positivity (‘+’ reactions and higher) or irritant reactions using a test preparation with alcohol 20% (Chemotechnique MB Diagnostics, Vellinge, Sweden) on days 2 and 4 of patch testing in a cosmetic series were retrieved between 2013 and 2022 from a total of 5458 people tested. Data collected from records included degree of positivity, irritancy, relevance, coexisting allergens, primary anatomical site and previous history of atopy. Data were processed using Microsoft Excel. We report 21 positive reactions, 14 (67%) of which were weak. Eleven (52%) positive reactions were deemed of current relevance, seven (33%) of doubtful relevance, one (5%) of past relevance and one (5%) a crossreaction to fragrance. Seven (25%) patients had documented irritant reaction to shellac. Nickel and colophony were the most common coexisting allergens in shellac-positive patients (positive in five and four cases, respectively). Nine (43%) cases with positive reaction had coexisting positivity of fragrance markers (which included one or more of geraniol, citral, Evernia furfuracea, turpentine, propolis, colophony, abitol, isoeugenol, cinnamyl alcohol, Jasminum officinale, jasmine absolute, majantole or benzaldehyde), indicating a higher prevalence than existing rates from studies in the general population. Fourteen (67%) positive cases documented the face as the primary site of disease, and 16 (76%) had a personal history of atopy. Our results indicate a significant association between shellac positivity and coexisting fragrance allergy, suggesting a role as a marker of fragrance allergy due to cross-reaction. When comparing irritant reactions to the proportion of positive reactions, this was higher than in previous US population-based reports (five irritant cases vs. 64 positive cases of a total cohort of 612 cases) but significantly lower than in a recent German population-based study (90 irritant cases vs. 76 positive cases of a total cohort of 2167), in all instances using the alcohol 20% preparation.

The European baseline series was last updated in 2019. This article discusses the reasoning behind a further iteration of the series for 2023.

We describe a case of Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS) to multiple CFTR modulators and piperacillin in an 8 year old female with CF. To our knowledge this is the first reported case of delayed type, T-cell mediated hypersensitivity to multiple CFTR modulators described in literature. Our findings suggest possible cross-reactivity between CFTR modulators or multiple sensitisations, which should be taken into account in similar cases.

CD01 The ‘extended’ facial series audit: recommendation to include shellac and sodium benzoate in the British Society of Cutaneous Allergy Facial Series Sophie Rolls, Deirdre Buckley, Mahubub M.U. Chowdhury, Simon Dawe, Catherine Holden, Faheem Latheef, Avad Mughal, Birgit Pees, Asha Rajeev, Ruth Sabroe, Livia F. Sorano, Donna Thompson, Heather Whitehouse, Mark Wilkinson and Natalie Stone The Royal Gwent Hospital, Newport, UK; Royal United Bath Hospital, Bath, UK; Cardiff and Vale University Health Board, Cardiff, UK; West Hereford NHS Trust, Hereford, UK; Sheffield Teaching Hospital NHS Trust, Sheffield, UK; Leeds Teaching Hospital NHS Trust, Leeds, UK; Neath and Port Talbot Hospital, Port Talbot, UK; University Hospital Southampton NHS Trust, Southampton, UK; East Kent Hospital University NHS Trust, Kent, UK; and Sandwell and West Birmingham Hospital NHS Trust, Birmingham, UK The British Society of Cutaneous Allergy (BSCA) updated the BSCA facial series in 2019. Seven allergens of undetermined importance were identified and were not included on the 2019 updated BSCA facial series. The BSCA proposed further assessment of the relevance of these seven allergens, and created an ‘extended series’, including butylated hydroxytoluene (BHT; 2,6-di-tert-butyl-4-cresol) 2% pet.; butylhydroxyanisole (BHA; 2-tert-butyl-4-methoxyphenol) 2% pet.; dimethyl dimethylol (DMDM) hydantoin 2% aq.; ethylhexylglycerin 5% pet.; methoxybenzophenone (benzophenone 3, oxybenzone) 10% pet.; shellac 20% alc.; and sodium benzoate 5% pet. We audited data from 10 UK patch test centres on this extended series over the 12-month period between October 2020 and September 2021. We calculated the rate of positive patch tests to each allergen. A 0 3% positive rate was defined as the threshold to warrant inclusion of an allergen in the facial series, the same threshold that had been used when updating the BSCA Facial Series. The total number of patients tested to each allergen ranged from 1457 (shellac) to 1948 (BHT). The positive rate for each allergen was: BHA 0 2%; BHT 0 2%; DMDM hydantoin 0 2%; ethylhexylglycerin 0 0%; methoxybenzophenone 0 0%; shellac 0 5%; and sodium benzoate 1 5%. BHA, BHT and DMDM hydantoin had positive patch test rates just below the inclusion threshold. Shellac and sodium benzoate had a positive pick-up rate > 0 3%. Relevance was found in 43% of patients with a positive patch test to sodium benzoate, including Aveeno and Sanex body washes and Palmer’s Coconut Oil Formula Body Lotion. This audit of the extended facial series demonstrates the importance and relevance of shellac and sodium benzoate, each of which was positive in > 0 3% of those selected for testing. Shellac 20% in alcohol also has irritant potential. Reading ingredient labels and additional patch testing with patient’s own products are both important, to ensure that positive results have clinical relevance. We recommend the addition of shellac and sodium benzoate to the BSCA Facial Series.

To review the European baseline series (EBS). The EBS is a core set of haptens that are used to patch test a patient, when an allergic contact dermatitis (ACD) is suspected. The EBS is intended specifically as a screen to be supplemented by additional tests/test series determined by the patient’s history and identified exposures. Hazards can vary within a single population, as well as between populations, as exposure to environmental haptens changes with time. Hence, the EBS needs to be adapted to capture the shifts in exposure. This article discusses these shifts in exposure and hence potential additions and deletions from the EBS. The formaldehyde-releasing preservatives imidazolidinyl urea 2% pet., diazolidinyl urea 2% pet. and 2-bromo-2-nitropropane-1,3-diol 0.5% pet. should be considered for inclusion in the EBS as published data has shown formaldehyde 2% aq. is an inadequate screen for contact allergy to the formaldehyde releasers. Other potential additions include isothiazolinones preservatives, sodium metabiosulphite, linalool hydroperoxide and limonene hydroperoxide, Compositae mix II, sorbitan monooleate and sorbitan sesquioleate, and the emulsifiers decyl glucoside and lauryl glucoside. Potential deletions include paraben mix and methyldibromogluterile nitrile (MDBGN). Dermatologists who investigate patients for potential ACD have an important role to play in monitoring trends in contact allergy including cosmetovigilance by thoroughly investigating patients and in the subsequent detection and reporting of emerging allergens. Further reports on newly identified allergens create a body of evidence to indicate whether the allergens need to be included in a series of commercially available test allergens. We have discussed a number of emerging allergens which have achieved sufficient evidence to merit their inclusion in the EBS.