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Background: Identification of allergens causing medical adhesive contact allergy is difficult., Objective: To characterize the demographics, clinical characteristics, patch test results, and occupational data for North American Contact Dermatitis Group patients with medical adhesive contact allergy., Methods: A retrospective study of 43,722 North American Contact Dermatitis Group patients patch tested from 2001 to 2018 with medical adhesive (tapes/bandaids/adhesive aids/suture glue) sources, positive patch test results, and final primary diagnoses of allergic contact dermatitis., Results: In total, 313 (0.7%) patients met the inclusion criteria. Compared with other patients with final primary diagnoses of allergic contact dermatitis, patients with a medical adhesive allergy were less likely to be male (odds ratio, 0.58; 95% CI, 0.45-0.77) and/or aged >40 years (odds ratio, 0.76; 95% CI, 0.60-0.96). The most common North American Contact Dermatitis Group screening series allergens were colophony (80.7%), balsam of Peru (3.9%), 2-hydroxyethyl methacrylate (2.7%), and carba mix (2.7%). One-fourth of the patients (79/313, 25.2%) had positive patch test reactions to supplemental allergens/materials, and 54 (17.3%) of the 313 patients only had reactions to supplemental allergens/materials., Limitations: Results of comprehensive patch testing may be prone to referral population selection bias and may not be representative of the general dermatology population., Conclusion: Colophony was the most common allergen. Supplemental allergens and materials should be tested in the evaluation of a suspected medical adhesive contact allergy., Competing Interests: Conflicts of interest Dr Taylor has consulted for Johnson & Johnson, Bayer, Kao Brands, and Equinox Group; received royalties from Decision Support in Medicine; owns noncontrolling shares of common stock in AstraZeneca, Cigna, Johnson & Johnson, Merck, and Opko Health; and is a member of the Steering Committee of the Cosmetic Ingredient Review; a nondependent child is an employee of Pfizer. Dr Reeder is the American Contact Dermatitis Society Contact Allergy Management Program Director. Drs Sasseville and Reeder receive royalties from UpToDate (Wolters Kluwer Health). Dr Atwater received the Pfizer Independent Grant for Learning & Change, has consulted for Henkel, and is currently employed by Eli Lilly and Company. Dr Warshaw has received an investigator-initiated grant from and served as a consultant for Wen by Chaz Dean and served as a consultant for Noven Pharmaceuticals. Drs Bembry, Liu, DeKoven, Silverberg, Zug, Houle, Belsito, Maibach, Dunnick, Fowler, Pratt, and DeLeo have no conflicts of interest to declare., (Copyright © 2021 American Academy of Dermatology, Inc. All rights reserved.)

Background: Shoe contact allergy can be difficult to diagnose and manage., Objective: The aim of the study was to characterize demographics, clinical characteristics, patch test results, and occupational data for the North American Contact Dermatitis Group patients with shoe contact allergy., Methods: This is a retrospective study of 33,661 patients, patch tested from 2005 to 2018, with a shoe source, foot as 1 of 3 sites of dermatitis, and final primary diagnosis of allergic contact dermatitis., Results: Three hundred fifty-two patients met the inclusion criteria. They were more likely to be male (odds ratio = 3.36, confidence interval = 2.71-4.17) and less likely to be older than 40 years (odds ratio = 0.49, confidence interval = 0.40-0.61) compared with others with positive patch test reactions. The most common relevant North American Contact Dermatitis Group screening allergens were potassium dichromate (29.8%), p-tert-butylphenol formaldehyde resin (20.1%), thiuram mix (13.3%), mixed dialkyl thioureas (12.6%), and carba mix (12%). A total of 29.8% (105/352) had positive patch test reactions to supplemental allergens, and 12.2% (43/352) only had reactions to supplemental allergens., Conclusions: Shoe contact allergy was more common in younger and male patients. Potassium dichromate and p-tert-butylphenol formaldehyde resin were the top shoe allergens. Testing supplemental allergens, personal care products, and shoe components should be part of a comprehensive evaluation of suspected shoe contact allergy., Competing Interests: J.S.T. has consulted for Johnson & Johnson, Bayer, Kao Brands, and Equinox Group; received royalties from Decision Support in Medicine; and owns noncontrolling shares of common stock in AstraZeneca, Cigna, Johnson & Johnson, Merck, and Opko Health; a nondependent child is an employee of Pfizer. He is a member of the Steering Committee of the Cosmetic Ingredient Review. M.J.R. is the American Contact Dermatitis Society Contact Allergy Management Program Director. D.S. receives royalties from UpToDate (Wolters Kluwer Health). A.R.A. received the Pfizer Independent Grant for Learning & Change and has consulted for Henkel. E.M.W. has received an investigator-initiated grant from and served as a consultant for Wen by Chaz Dean. She has also served as a consultant for Noven Pharmaceuticals. The other authors have no funding or conflicts of interest to declare., (Copyright © 2021 American Contact Dermatitis Society. All Rights Reserved.)

Background: Hair care products (HCPs) may cause both allergic contact dermatitis (ACD) and irritant contact dermatitis (ICD)., Objectives: The aims of the study were to determine the prevalence of HCP-associated ICD/ACD and to characterize relevant allergens., Methods: This study is a retrospective analysis of North American Contact Dermatitis Group (NACDG) patch test data, 2001-2016., Results: Of 38,775 patients tested, 3481 (9.0%) had positive patch test reactions associated with HCPs. The HCP-positive patients were significantly more likely to be female (79.9% vs 66.0%) and/or have primary sites of dermatitis on the face (32.0% vs 27.8%) or scalp (15.4% vs 2.2%) compared with the HCP-negative patients (P < 0.0001). Of 4908 HCP-associated positive patch test reactions, 86.9% (n = 4263) were due to allergens on the NACDG screening series; p-phenylenediamine (35.8%), methylisothiazolinone (9.7%), methylchloroisothiazolinone/methylisothiazolinone (8.7%), and cocamidopropyl betaine (5.9%) were the most frequent. Most reactions (87.7%, 3736/4263) were currently clinically relevant. The most common job associated with 366 occupationally related NACDG HCP-associated allergens was hairdresser/cosmetologist (71.9%). Two hundred eighty-two patients (0.7%) had ICD associated with HCPs. Shampoo/conditioners were the most frequent source of NACDG HCP-associated reactions (47.3%) and HCP-associated ICD (45.0%)., Conclusions: Of the HCP-positive patients, 18.5% had HCP reactions to allergens not on the NACDG screening series, underscoring the importance of patch testing to expanded series in patients suspected of HCP allergy., Competing Interests: A.R.A. received a Pfizer Independent Grant for Learning & Change and has consulted for Henkel. E.M.W. has received research funding from WEN by Chaz Dean. She has also served as a consultant for Noven Pharmaceuticals, Inc, and WEN by Chaz Dean. J.S.T. owns shares of stock in AstraZeneca, Cigna, Merck, Johnson & Johnson, and OPKO Health. He has consulted for Kao Brands and Monsanto (Bayer), is a member of the Cosmetic Ingredient Review Steering Committee, and has a nondependent child employed by Pfizer. Sasseville receives royalties from UpToDate (Wolters Kluwer Health). The other authors have no funding or conflicts of interest to declare., (Copyright © 2021 American Contact Dermatitis Society. All Rights Reserved.)

Background: Personal care products (PCPs) are commonly responsible for allergic contact dermatitis and irritant contact dermatitis. PCP use was historically associated with females, but male-targeted PCPs are increasingly being marketed., Objective: To characterize and compare males with PCP-related contact dermatitis (MPCPs) and females with PCP-related contact dermatitis (FPCPs)., Methods: This was a retrospective cross-sectional analysis of North American Contact Dermatitis Group data (1996-2016)., Results: Four thousand six hundred eighty of 16,233 men (28.8%) and 12,730 of 32,222 (39.5%) women had a PCP identified as a source of irritant contact dermatitis or a positive patch test reaction. The proportion of PCP-related dermatitis in both sexes significantly increased (>2.7-fold) over the decade of study. Compared with FPCPs, a larger proportion of MPCPs were older or had trunk or extremity dermatitis (P < .0001). MPCPs were twice as likely to have soaps as a source while FPCPs were twice as likely to have hair care products (P < .0001). The most common PCP-related North American Contact Dermatitis Group allergens for both sexes were methylisothiazolinone (MPCP 28.8% and FPCP 21.5%), fragrance mix I (MPCP 22.3% and FPCP 20.1%), balsam of Peru (MPCP 18.5% and FPCP 14.1%), quaternium-15 (MPCP 16.1% and FPCP 12.3%), and paraphenylenediamine (MPCP 11.5% and FPCP 11.1%)., Limitations: Patient population referred for suspected contact dermatitis., Conclusions: PCP-related dermatitis is increasing. Sites of involvement and relevant PCP sources are distinct between sexes. Male and female variation in exposure history may explain differences in reactivity to some allergen groups., (Published by Elsevier Inc.)

Competing Interests: The authors have no funding or conflicts of interest to declare.

Background: Few studies have examined the relationship between nummular (discoid) eczema (NE) and allergic contact dermatitis (ACD)., Objective: To examine trends, associations, and clinical relevance of ACD in patients with NE who were referred for patch testing., Methods: Retrospective analysis of 38 723 patients from the North American Contact Dermatitis Group., Results: Overall, 748 patients (1.9%) were diagnosed with NE; 23.9% had a concomitant diagnosis of ACD. The prevalence of NE fluctuated over time between 2001 and 2016, with no overall change in prevalence in diagnosed NE. In multivariable logistic regression models, NE increased steadily with age and was associated with male sex and Asian and other race/ethnicity, and inversely associated with a history of atopic dermatitis (AD) and hay fever. Patients with NE had lower proportions of one or more positive allergic reactions and lower odds of a positive reaction in multiple individual allergens. The most commonly relevant allergens in patients with NE were formaldehyde 2.0% aq., methylisothiazolinone, quaternium 15, fragrance mix I, and propylene glycol., Conclusion: NE is a heterogeneous disorder with distinct subsets of lesional distributions and a profile of relevant allergens, especially formaldehyde and formaldehyde releasers. Nearly one in four patients with NE had ACD, supporting the role of patch testing in patients with NE., (© 2021 John Wiley & Sons A/S . Published by John Wiley & Sons Ltd.)

Background/objective: This study characterizes concomitant reactions to carba mix (CM) and thiuram mix (TM) in a large North American population. Because thiurams and dithiocarbamates have structural similarity, concomitant reactions are expected., Methods: The 1994-2016 North American Contact Dermatitis Group data were analyzed. Patients with a final reaction interpreted as "allergic" to either CM or TM were included., Results: A total of 49,758 patients were tested to both CM and TM. A total of 3437 (6.9%) had positive reactions to CM and/or TM including the following groups: CM+ only (n = 1403, 40.8%), TM+ only (n = 1068, 31.0%), or both (n = 966, 28.1%). A total of 47.5% of TM+ patients were positive to CM and 40.8% of CM+ patients were positive to TM. Male sex, occupationally related dermatitis, and hand involvement were significantly more common in individuals positive to CM and/or TM as compared with those who were negative (P < 0.0001). More than 80% of CM+/TM+ reactions were currently relevant. Gloves were the most common source of CM and TM; clothing and footwear were also frequent., Conclusions: Carba mix and TM remain important, clinically relevant allergens. Although significant concomitant reaction frequency was demonstrated, more than half of the patients reacting to either CM or TM would have been missed if both had not been tested, underscoring the importance of testing to both., Competing Interests: J.S.T. owns noncontrolling common stock shares in AstraZeneca, Cigna, Merck, Johnson & Johnson, and Opko Health. He has consulted for Kao Brands and Monsanto (Bayer), is a member of the Cosmetic Ingredient Review Steering Committee, and has a nondependent child who is employed by Pfizer. The other authors have no conflicts of interest to declare., (Copyright © 2020 American Contact Dermatitis Society. All Rights Reserved.)

Background: Patch testing is an important diagnostic tool for assessment of allergic contact dermatitis (ACD)., Objective: This study documented the North American Contact Dermatitis Group (NACDG) patch testing results from March 1, 2017, to December 31, 2018., Methods: At 14 centers in North America, patients with dermatitis were tested in a standardized manner with a screening series of 70 allergens and supplemental allergens as clinically indicated. Data were manually verified and entered into a central database. Descriptive statistics were estimated, and trends were analyzed using χ2 test., Results: Overall, 4947 patients were tested. There were 3235 patients (65.4%) who had at least 1 positive reaction and 2495 patients (50.4%) had a primary diagnosis of ACD. Five hundred eighty-one patients (11.7%) had occupationally related dermatitis. There were 10,122 positive patch test reactions. Nickel remained the most commonly detected allergen (16.2%), followed by methylisothiazolinone 0.2% aqueous (15.3%) and methylchloroisothiazolinone/methylisothiazolinone 0.02% aqueous (200 ppm, 11.0%). Compared with the previous reporting periods (2015-2016 and 2007-2016), the proportion of positive reactions for the top 20 screening allergens statistically increased for only 1 allergen, propolis (3.4%; risk ratios = 2.05 [confidence interval = 1.66-2.54] and 1.82 [confidence interval = 1.57-2.11]).Four newly added allergen preparations, hydroperoxides of linalool (8.9%), benzisothiazolinone (7.3%), sodium metabisulfite (2.7%), and hydroperoxides of limonene (2.6%), all had a prevalence of greater than 2%. Approximately 1 (19.7%) in 5 tested patients had 1 or more clinically relevant reactions to an allergen not on the NACDG screening series; 13.2% of these were occupationally related. T.R.U.E. TEST (SmartPractice Denmark, Hillerød, Denmark) would have hypothetically missed 30% to 40% of reactions detected by the NACDG screening series., Conclusions: These results demonstrate the importance of a regularly updated screening allergen series. Methylisothiazolinone continues to be a significant allergen in North America. Patch testing with allergens beyond a screening tray is necessary for complete evaluation of occupational and non-occupational ACD., Competing Interests: E.M.W. has received an investigator-initiated grant from Wen by Chaz Dean and served as a consultant for Wen by Chaz Dean and Noven Pharmaceuticals. A.R.A. received a grant from Pfizer Independent Grant for Learning & Change and has consulted for Henkel. D.S. receives royalties from UpToDate (Wolters Kluwer Health). J.S.T. owns noncontrolling shares of stock in AstraZeneca, Cigna, Merck, Johnson & Johnson, and Opko Health. He has consulted for Kao Brands and Monsanto (Bayer), is a member of the Cosmetic Ingredient Review Steering Committee, and has a non-dependent child employed by Pfizer. The other authors have no funding or conflicts of interest to declare., (Copyright © 2021 American Contact Dermatitis Society. All Rights Reserved.)

Importance: When fragrance- and botanical-related (F/BR) allergy is identified, concomitant reaction (CR) frequencies can help direct avoidance recommendations., Objective: This study aimed to determine the CR rates for F/BR allergens., Design: A retrospective cross-sectional analysis of the North American Contact Dermatitis Group data 2007-2016 was conducted. Frequencies of demographics, positive reactions, strength of reactions, trends, and CR rates were calculated., Results: A total of 5504 (22.7%) of 24,246 patients had F/BR allergic reactions. The F/BR-sensitive patients were more likely to be female, older than age 40 years, and White and have face, leg, or anal/genital dermatitis. Top allergens included fragrance mix I (FMI, 10.6%), Myroxylon pereirae (balsam of Peru [BOP], 8%), and fragrance mix II (FMII, 4.9%). There were increasing trends for FMI, FMII, cinnamic aldehyde, and Compositae mix and decreasing trends for BOP and propolis. When patients were positive to any F/BR allergen, they were likely to be positive to FMI, FMII, and BOP. Concomitant reactions were bidirectional between multiple fragrance allergens and propolis, colophony, and Compositae mix., Conclusions: Concomitant reactions were identified between fragrances, between fragrances and BR allergens, and between BR allergens and fragrances. If CRs of greater than 10% suggest cross-reactivity, then all patients with fragrance sensitivity should avoid BR allergens and vice versa., Competing Interests: The authors have no funding or conflict of interest to declare., (Copyright © 2020 American Contact Dermatitis Society. All Rights Reserved.)

Importance: Contact dermatitis in the anogenital area is associated with sleep disturbance and dyspareunia and can profoundly affect quality of life. The literature on anogenital contact dermatitis and culprit allergens is limited. The last large-scale study on common, relevant allergens in patients with anogenital dermatitis was published in 2008., Objectives: To characterize patients with anogenital dermatitis referred for patch testing by the North American Contact Dermatitis Group, to identify common allergens, and to explore sex-associated differences between anogenital dermatitis and allergens., Design, Setting, and Participants: A retrospective, cross-sectional analysis was conducted of the North American Contact Dermatitis Group database among 28 481 patients who underwent patch testing from January 1, 2005, to December 31, 2016, at outpatient referral clinics in the United States and Canada., Exposure: Patch testing for allergens., Main Outcomes and Measures: Currently relevant allergic patch test reactions in patients with anogenital dermatitis., Results: Of 28 481 patients tested during the study period, 832 patients (336 men and 496 women; mean [SD] age, 50.1 [26.5] years) had anogenital involvement and 449 patients (177 men and 272 women; mean [SD] age, 49.6 [17.4] years) had anogenital dermatitis only. Compared with those without anogenital involvement, there were significantly more male patients in the group with anogenital dermatitis (177 [39.4%] vs 8857 of 27 649 [32.0%]; relative risk, 1.37; 95% CI, 1.14-1.66; P < .001). In the group with anogenital involvement, female patients were significantly less likely than male patients to have allergic contact dermatitis as a final diagnosis (130 [47.8%] vs 107 [60.5%]; relative risk, 0.78; 95% CI, 0.64-0.94; P = .01), whereas a final diagnosis of other dermatoses (eg, lichen planus, lichen sclerosus, or lichen simplex chronicus) was more frequent for female patients than for male patients (67 [24.6%] vs 28 [15.8%]; relative risk, 1.54; 95% CI, 1.02-2.31; P = .03). Of the 449 patients in the group with anogenital involvement only, 227 (50.6%) had 1 or more relevant reaction with patch testing. Allergens that were statistically significantly more common in patients with anogenital involvement compared with those without anogenital involvement included medicaments such as dibucaine (10 of 250 patients tested [4.0%] vs 32 of 17 494 patients tested [0.2%]; relative risk, 22.74; 95% CI, 11.05-46.78; P < .001) and preservatives such as methylchloroisothiazolinone and methylisothiazolinone (30 of 449 patients tested [6.7%] vs 1143 of 27 599 patients tested [4.1%]; relative risk, 1.61; 95% CI, 1.14-2.41; P = .008). A total of 152 patients met the definition for anogenital allergic contact dermatitis, which is defined as anogenital involvement only, allergic contact dermatitis as the only diagnosis, and 1 or more positive reaction of current clinical relevance., Conclusions and Relevance: For patients with anogenital involvement only who were referred for patch testing, male patients were more likely to have allergic contact dermatitis, whereas female patients were more likely to have other dermatoses. Common allergens or sources consisted of those likely to contact the anogenital area. For individuals with anogenital involvement suspected of having allergic contact dermatitis, reactions to preservatives, fragrances, medications (particularly topical anesthetics), and topical corticosteroids should be tested.

Importance: Facial dermatitis in women is well characterized. However, recent shifts in the men's grooming industry may have important implications for male facial dermatitis., Objective: To characterize male patients with facial dermatitis., Design, Setting, and Participants: A 22-year retrospective cross-sectional analysis (1994-2016) of North American Contact Dermatitis Group (NACDG) data, including 50 507 patients who underwent patch testing by a group of dermatology board-certified patch test experts at multiple centers was carried out. Facial dermatitis was defined as involvement of the eyes, eyelids, lips, nose, or face (not otherwise specified)., Main Outcomes and Measures: The main outcome was to compare characteristics (including demographics and allergens) between male patients with facial dermatitis (MFD) and those without facial dermatitis (MNoFD) using statistical analysis (relative risk, CIs). Secondary outcomes included sources of allergic and irritant contact dermatitis and, for occupationally related cases, specific occupations and industries in MFD., Results: Overall, 1332 male patients (8.0%) were included in the MFD group and 13 732 male patients (82.0%) were included in MNoFD. The mean (SD) age of participants was 47 (17.2) years in the MFD group and 50 (17.6) years in the MNoFD group. The most common facial sites were face (not otherwise specified, 817 [48.9%]), eyelids (392 [23.5%]), and lips (210 [12.6%]). Participants in the MFD group were significantly younger than MNoFD (mean age, 47 vs 50 years; P < .001). Those in the MFD group were less likely to be white (relative risk [RR], 0.92; 95% CI, -0.90 to 0.95) or have occupationally related skin disease (RR, 0.49; 95% CI, -0.42 to 0.58; P < .001) than MNoFD. The most common allergens that were associated with clinically relevant reactions among MFD included methylisothiazolinone (n = 113; 9.9%), fragrance mix I (n = 27; 8.5%), and balsam of Peru (n = 90; 6.8%). Compared with MNoFD, MFD were more likely to react to use of dimethylaminopropylamine (RR, 2.49; 95% CI, -1.42 to 4.37]) and paraphenylenediamine (RR, 1.43; 95% CI, -1.00 to 2.04; P < .001). Overall, 60.5% of NACDG allergen sources were personal care products., Conclusions and Relevance: Although many allergens were similar in both groups, MFD were more likely to react to use of dimethylaminopropylamine and paraphenylenediamine, presumably owing to their higher prevalence in hair products. Most sources of allergic and irritant contact dermatitis in MFD were personal care products. This study provides insight into the risks and exposures of the increasing number of grooming products used by male dermatology patients. This will enable clinicians to better identify male patients who would benefit from patch testing and treat those with facial dermatitis.

Background: Patch testing is an important diagnostic tool for the assessment of allergic contact dermatitis (ACD)., Objective: This study documents the North American Contact Dermatitis Group (NACDG) patch testing results from January 1, 2015, to February 28, 2017., Methods: At 13 centers in North America, patients were tested in a standardized manner with a screening series of 70 allergens. Data were manually verified and entered into a central database. Descriptive frequencies were calculated, and trends were analyzed using χ test., Results: A total of 5597 patients were tested. There were 3725 patients (66.6%) who had at least 1 positive reaction, and 2798 patients (50.2%) were ultimately determined to have a primary diagnosis of ACD. A total of 572 patients (10.2%) had occupationally related skin disease. There were 10,983 positive allergic reactions. Nickel remained the most commonly detected allergen (17.5%). Methylisothiazolinone, which was added to the screening series for the 2013-2014 cycle, had the second highest positive reaction rate of allergens tested (13.4%). Compared with the previous reporting periods (2013-2014) and (2005-2014), positive reaction rates for the top 35 screening allergens statistically increased for only 1 allergen: hydroxyethyl methacrylate (3.4%; risk ratios, 1.24 [confidence interval, 1.00-1.54] and 1.46 [confidence interval, 1.23-1.73]). Three newly added allergen preparations-ammonium persulfate (1.7%), chlorhexidine (0.8%), and hydroquinone (0.3%)-all had a reaction rate of less than 2%. Twenty-three percent of the tested patients had at least 1 relevant allergic reaction to an allergen not on the NACDG series; 12% of these were occupationally related. T.R.U.E. Test (SmartPractice Denmark, Hillerød, Denmark) would have hypothetically missed one quarter to almost 40% of reactions detected by the NACDG screening series., Conclusions: These results confirm that the epidemic of sensitivity to methylisothiazolinone has continued in North America. Patch testing with allergens beyond a screening tray is necessary for a complete evaluation of occupational and nonoccupational ACD.

Background: Synthetic fragrances and natural essential oils (EOs) are used in perfumery and found in various cosmetics. Essential oils are also increasingly used to promote wellness. In previous studies, the sensitization potential of some EOs has been identified; however, the current prevalence of sensitivity is largely unknown., Objectives: The aim of this study was to determine frequency of positive patch-test reactions to EOs tested in the baseline series, along with 3 fragrance markers (FMs) (fragrance mix I, fragrance mix II, and Myroxylon pereirae), in consecutive patients in the US/Canadian North American Contact Dermatitis Group (NACDG) (2009-2014) and the central European, trinational Information Network of Departments of Dermatology (IVDK) (2010-2014)., Methods: This study used a retrospective analysis of patch-test results and relevant demographic/clinical data collected electronically by the networks, obtained with Santalum album 10% petrolatum (pet) (IVDK only); Cananga odorata 2% (NACDG) and 10% (IVDK) pet; Jasminum species 2% (NACDG) and 5% (IVDK) pet; Mentha piperita 2% pet; Melaleuca alternifolia, oxidized (tea tree oil), 5% pet; and Lavandula angustifolia 2% pet (latter 3 NACDG only)., Results: Overall, 62,354 patients were tested to 3 FMs and EOs (NACDG, 13,398; IVDK, 48,956); 11,568 (18.6%) reacted to at least 1 FM or EO, whereas 857 (1.4%) reacted to 1 or more EOs but none of the 3 FMs. For both the NACDG and IVDK populations, individuals who were positive to 1 or more of the 9 study allergens were significantly less likely to be male, have occupational skin disease, or have hand involvement and significantly more likely to have leg dermatitis and be 40 years and older (P's ≤ 0.005). Prevalence rates for EOs were as follows: S. album, 1.4% IVDK; C. odorata, 1.1% NACDG and 2.4% IVDK; Jasminum species, 0.7% NACDG and 1.4% IVDK; M. piperita, 0.9% NACDG; L. angustifolia, 0.3% NACDG; and M. alternifolia, 0.3% NACDG. Of the 140 NACDG patients who reacted to 1 or more of the 5 NACDG EOs but none of the FMs, M. alternifolia yielded most positive reactions (45%); half of these reactions were strong (++ or +++, 50.8%) and of definite/probable clinical relevance (52.4%). Of the 717 IVDK patients who reacted to 1 or more of the 3 IVDK EOs but none of the 3 FMs, 38% were positive to C. odorata, 38% to S. album and 36% to Jasminum species.', Conclusions: Testing to EOs may be important for detecting sensitivity not detected by FMs alone. In North America, M. alternifolia is an important and clinically relevant sensitizer often not detected by FM. In Europe, as well as in North America, clinical relevance is often difficult to evaluate because (1) labeling of EOs when used as fragrance is not mandatory, and (2) these mixtures may indicate sensitization to 1 or more of their individual constituents from other sources, including synthetic fragrances.

Background: Little is known about the epidemiology of contact dermatitis (CD) in print machine operators (PMOs)., Objective: The aims of this study were to estimate the prevalence of CD and characterize clinically relevant and occupationally related allergens among PMOs undergoing patch testing., Methods: This was a retrospective cross-sectional analysis of the North American Contact Dermatitis Group data from 1998 to 2014., Results: Of 39,332 patch-tested patients, 132 (0.3%) were PMOs. Among PMOs, most were male (75.0%) and white (92.4%). The majority were printing press operators (85.6%). The most frequent sites of dermatitis were hands (63.6%), arms (29.5%), and face/scalp (24.2%). More than half had an occupationally related skin condition (56.1%). Final diagnoses were most commonly allergic CD (58.3%) and irritant CD (33.3%). Cobalt (20.8%), carba mix (12.5%), thiuram mix (8.3%), and formaldehyde (8.3%) were the most frequent occupationally related allergens. The top allergen sources included inks (22.9%), gloves (20.8%), and coatings/dye/copy/photographic chemicals (14.6%)., Conclusions: Allergic CD, irritant CD, and involvement of exposed body areas were common among PMOs. Common allergens included rubber accelerators, metals, and preservatives.

Background: Little is known about the epidemiology of contact dermatitis in production workers (PWs)., Objective: The aims of this study were to estimate the prevalence of contact dermatitis and characterize clinically relevant and occupationally related allergens among North American PWs undergoing patch testing., Methods: This was a retrospective cross-sectional analysis of North American Contact Dermatitis Group data from 1998 to 2014., Results: Of 39,332 patch-tested patients, 2732 (7.0%) were PWs. Among PWs, most were men (62.4%) and white (83.9%). A history of childhood eczema was uncommon (11.3%). Prevalent occupations included machine operators (27.3%); fabricators, assemblers, and hand-working occupations (16.8%); and precision metalworking occupations (16.1%). The most frequent sites of dermatitis were the hands (53.8%) and arms (29.4%), which were significantly more commonly affected compared with non-PWs (P < 0.0001). Occupationally related skin disease, allergic contact dermatitis, and irritant contact dermatitis were also significantly more common in PWs (49.9% vs 10.6%, 58.9% vs 53.7%, and 32.7% vs 25.7%, respectively; all Ps < 0.0001). Epoxy (15.3%), thiuram mix (8.3%), carba mix (8.1%), formaldehyde (6.3%), and cobalt (5.9%) were the most frequent occupationally related allergens. The top allergen sources included adhesives/glues (16.0%), metalworking fluids/cutting oils (6.8%), and coatings (6.3%)., Conclusions: Production workers had a high rate of occupationally related skin disease, as well as irritant and allergic contact dermatitis. Involvement of exposed body areas was common. Frequently identified allergens included adhesives/glues, rubber accelerators, metals, and preservatives.

Background: Contact dermatoses are common in mechanic and repair occupations., Objectives: This study aimed to (1) estimate the prevalence of occupationally related contact dermatitis among mechanics/repairers patch tested from 1998 to 2014 by the North American Contact Dermatitis Group, (2) characterize responsible allergens and irritants, and their sources, and (3) compare results among 3 occupational subgroups (mechanics, electrical/electronic, and other)., Methods: A cross-sectional analysis of patients patch tested by the North American Contact Dermatitis Group between 1998 and 2014., Results: Of 38,784 patients patch tested, 691 (1.8%) were mechanics/repairers. Male sex (93.5%) and hand involvement (59.5%) were common overall. Occupationally related skin disease was more prevalent among vehicle and mobile equipment mechanics/repairers (52.7%) and other mechanics/repairers (41.4%) than electrical/electronic equipment mechanics/repairers (21.3%). Overall, carba mix, thiuram mix, and methylchloroisothiazolone/methylisothiazolone were the most common occupation-related clinically relevant allergens. Gloves, automotive vehicles, solvents, oils, lubricants, and fuels were the most common sources of responsible allergens., Conclusions: Common occupationally related allergens included rubber accelerators and the preservative methylchloroisothiazolone/methylisothiazolone.

Background: Patch testing is the most important diagnostic tool for the assessment of allergic contact dermatitis., Objective: This study documents the North American Contact Dermatitis Group (NACDG) patch testing results from January 1, 2013, to December 31, 2014., Methods: At 13 centers in North America, patients were tested in a standardized manner with a screening series of 70 allergens. Data were manually verified and entered into a central database. Descriptive frequencies were calculated, and trends were analyzed using χ test., Results: A total of 4871 patients were tested. There were 3255 patients (66.8%) who had at least 1 positive reaction and 2412 patients (49.5%) who were ultimately determined to have a primary diagnosis of allergic contact dermatitis. A total of 434 patients (8.9%) had occupationally related skin disease. There were 9726 positive allergic reactions. Compared with the previous reporting periods (2011-2012 and 2001-2012, including at least three 2-year cycles), positive reaction rates for the top 25 screening allergens statistically increased for 2 allergens: methylchloroisothiazolinone/methylisothiazolinone (6.4%; risk ratios, 1.26 [1.07-1.50] and 2.08 [1.84-2.37]) and hydroxyethyl methacrylate (2.6%; risk ratios, 1.34 [1.02-1.76] and 1.23 [1.00-1.51]). Methylisothiazolinone, which was added to the screening series for this 2013-2014 cycle, had the third highest positive reaction rate of allergens tested (10.9%). Four other newly added allergen preparations-formaldehyde 2% (7%), diphenylguanidine (3.8%), propylene glycol 100% (2.8%), and benzophenone-4 (2.1%)-all had reaction rates greater than 2%. Twenty-one percent of tested patients had at least 1 relevant allergic reaction to an allergen not on the NACDG series; 14.6% of these were occupationally related. The T.R.U.E. TEST (SmartPractice Denmark, Hillerød, Denmark) would have hypothetically missed one quarter to one third of reactions detected by the NACDG screening series., Conclusions: These results confirm that the epidemic of sensitivity to methylisothiazolinone previously documented in Europe is also occurring in North America. Patch testing with allergens beyond a standard screening tray is necessary for the complete evaluation of occupational and nonoccupational allergic contact dermatitis.

Background: Although there are several case reports of wet wipe-associated contact dermatitis, the prevalence of wipes as a source of allergic contact dermatitis in larger populations and the responsible allergens are largely unknown., Objective: The aim of the study was to determine the prevalence of wet wipes as a source of contact allergy and the most commonly associated allergens in a North American tertiary referral patch test population., Methods: Data collected from 2011 to 2014 by the North American Contact Dermatitis Group was used to conduct a retrospective cross-sectional analysis of patient demographics and patch test results associated with the triple-digit source code for "wet wipe.", Results: Of the 9037 patients patch tested during the study period, 79 (0.9%) had a positive patch test reaction to an allergen identified with a wet wipe source. The most commonly associated allergens were preservatives, including the following: methylisothiazolinone (MI) (59.0%), methylchloroisothiazolinone (MCI)/MI (35.6%), bronopol (2-bromo-2-nitropropane-1,3-diol) (27.4%), and iodopropynyl butylcarbamate (12.3%). Fragrance (combined) represented 12.3%. Anal/genital dermatitis was 15 times more likely (P < 0.0001) in those with wet wipe allergy. More than 92% of patients with wipe-associated contact allergy had their contact allergens detected by the North American Contact Dermatitis Group screening series., Conclusions: Wet wipes are an important source of contact allergy. Preservatives are the main allergens, especially isothiazolinones.

Cobalt has been a recognized allergen capable of causing contact dermatitis for decades. Why, therefore, has it been named 2016 "Allergen of the Year"? Simply put, new information has come to light in the last few years regarding potential sources of exposure to this metallic substance. In addition to reviewing some background on our previous understanding of cobalt exposures, this article will highlight the recently recognized need to consider leather as a major site of cobalt and the visual cues suggesting the presence of cobalt in jewelry. In addition, a chemical spot test for cobalt now allows us to better identify its presence in suspect materials.

Background: Patch testing is an important diagnostic tool for assessment of allergic contact dermatitis (ACD)., Objective: This study documents the North American Contact Dermatitis Group (NACDG) patch-testing results from January 1, 2011, to December 31, 2012., Methods: At 12 centers in North America, patients were tested in a standardized manner with a series of 70 allergens. Data were manually verified and entered into a central database. Descriptive frequencies were calculated, and trends analyzed using χ statistics., Results: Four thousand two hundred thirty-eight patients were tested; of these, 2705 patients (63.8%) had at least 1 positive reaction, and 2029 (48.0%) were ultimately determined to have a primary diagnosis of ACD. Four hundred eight patients (9.6%) had occupationally related skin disease. There were 7532 positive allergic reactions. As compared with previous reporting periods (2009-2010 and 2000-2010), positive reaction rates statistically increased for 6 allergens: methylchloroisothiazolinone/methylisothiazolinone (5.0%; risk ratios [RRs]: 2.01 [1.60-2.52], 1.87 [1.61-2.18]), lanolin alcohol (4.6%; RRs 1.83 [1.45-2.30], 2.10 [1.79-2.47]), cinnamic aldehyde (3.9%; 1.69 [1.32-2.15], 1.53 [1.28-1.82]), glutaral (1.5%; 1.67 [1.13-2.48], 1.31 [1.00-1.71]), paraben mix (1.4%; 1.77 [1.16-2.69], 1.44 [1.09-1.92]), and fragrance mix I (12.1%; RRs 1.42 [1.25-1.61], 1.24 [1.14-1.36]). Compared with the previous decade, positivity rates for all formaldehyde-releasing preservatives significantly decreased (formaldehyde 6.6%; RR, 0.82 [0.73, 0.93]; quaternium-15 6.4% RR 0.75 [0.66, 0.85]; diazolidinyl urea 2.1%; RR, 0.67 [0.54, 0.84]; imidazolidinyl urea 1.6%, 0.60 [0.47, 0.77]; bronopol 1.6%; RR, 0.60 [0.46, 0.77]; DMDM hydantoin 1.6%; RR, 0.59 [0.54, 0.84]). Approximately a quarter of patients had at least 1 relevant allergic reaction to a non-NACDG allergen. In addition, approximately one-fourth to one-third of reactions detected by NACDG allergens would have been hypothetically missed by T.R.U.E. TEST (SmartPractice Denmark, Hillerød, Denmark)., Conclusions: These data document the beginning of the epidemic of sensitivity to methylisothiazolinones in North America, which has been well documented in Europe. Patch testing with allergens beyond a standard screening tray is necessary for complete evaluation of occupational and nonoccupational ACD.

Background: Mercaptobenzothiazole (MBT) and mercapto compounds are primarily used in rubber products., Objective: This study aimed to examine concomitant-positive rates of MBT (1% pet) and the 4-part mercapto mix (MM) (1% pet)., Design: This is a retrospective cross-sectional data from the North American Contact Dermatitis Group., Results: A total of 30,880 patients were patch tested to MM and MBT. There were 333 positive reactions to MM and 427 positive reactions to MBT. Ninety-eight patients were positive to MM alone, 192 to MBT alone, and 235 reacted to both. Forty-five percent (192/427) of MBT reactions would have been missed by only testing to MM, and 29% (98/333) of MM reactions would have been missed by testing to MBT alone. Most of these "missed" reactions, however, were doubtful (+/-) or mild (+) (MBT, 65%; MM, 78%), whereas most reactions in patients who reacted to both were moderate (++) and/or strong (+++) (52.3%). Gloves were the most common source., Conclusions: Mercaptobenzothiazole is the preferential screening allergen for mercapto compounds because of the following: (1) greater proportion of missed reactions with MM; (2) greater proportion of doubtful/mild reactions in the missed group for MM; and (3) in the group positive to both, the low rate (2%) of moderate/strong reactions to MM and doubtful/mild reactions to MBT as compared with the converse (21%). Mercapto mix may be useful in an auxiliary rubber series.

Background: Carba mix (CM) contains 3 chemicals used as accelerators in manufacturing of rubber products and agricultural chemicals. Iodopropynyl butylcarbamate (IPBC) is a preservative used in industrial and personal care products. Potential cross-reactivity between these allergens is unclear., Objective: This study aimed to determine concomitant reaction rates between CM (3% petrolatum [pet]) and IPBC (0.1% pet and/or 0.5% pet)., Design: A retrospective cross-sectional analysis of data from the North American Contact Dermatitis Group from 1998 to 2008 was conducted. Frequencies of positive reactions, strength of reactions, and concomitant reaction rates were calculated., Results: A total of 25,435 patients were tested. There were 1131 allergic reactions to CM and 346 positive reactions to IPBC (either 0.1% pet and/or 0.5% pet). Fifty-two patients reacted to both allergens. Most reactions (>69%) were doubtful/weakly positive, and of those who reacted to both, most (58%) had doubtful and/or weakly positive reactions. There was a statistically significant association of concomitant reactions between CM and IPBC; formaldehyde positivity was used as control and showed statistically significant concomitant reactions., Conclusions: Overall, concomitant reactions to CM and IPBC were low, and rates varied by strength of reaction. True cross-reactivity is unlikely; statistical association is likely due to frequent low-grade reactions to irritant patch test preparations.

Background: Both active and inactive ingredients in sunscreen may cause contact dermatitis., Objectives: This study aimed to describe allergens associated with a sunscreen source., Methods: A cross-sectional analysis of patients patch tested by the North American Contact Dermatitis Group between 2001 and 2010 was performed., Results: Of 23,908 patients patch tested, 219 (0.9%) had sunscreen coded as an allergen source. Patients who were male, with occupational dermatitis, or older (older than 40 years) had significantly lower rates of allergic reactions to sunscreens; the most commonly affected areas were the face and exposed sites (P < 0.0001). The top 3 most frequent allergens in sunscreens were benzophenone-3 (70.2% for 10% concentration, 64.4% for 3% concentration), DL-alpha-tocopherol (4.8%), and fragrance mix I (4.0%). Less than 40% of positive patch test reactions were detected by the North American Contact Dermatitis Group screening series of 65 to 70 allergens., Conclusions: A supplemental antigen series is important in detecting allergy to sunscreens.

Background: The North American Contact Dermatitis Group (NACDG) tests patients with suspected allergic contact dermatitis to a broad series of screening allergens and publishes periodic reports., Objective: The aims of this study were to report the NACDG patch-testing results from January 1, 2007, to December 31, 2008, and to compare results to pooled test data from the previous 2 and 10 years to analyze trends in allergen sensitivity., Methods and Materials: Standardized patch testing with 65 allergens was used at 13 centers in North America. χ analysis was used for comparisons., Results: A total of 5085 patients were tested; 11.8% (598) had an occupationally related skin condition, and 65.3% (3319) had at least 1 allergic patch test reaction, which is identical to the NACDG data from 2005 to 2006. The top 15 most frequently positive allergens were nickel sulfate (19.5%), Myroxylon pereirae (11.0%), neomycin (10.1%), fragrance mix I (9.4%), quaternium-15 (8.6%), cobalt chloride (8.4%), bacitracin (7.9%), formaldehyde (7.7%), methyldibromoglutaronitrile/phenoxyethanol (5.5%), p-phenylenediamine (5.3%), propolis (4.9%), carba mix (4.5%), potassium dichromate (4.1%), fragrance mix II (3.6%), and methylchloroisothiazolinone/methylisothiazolinone (3.6%). There were significant increases in positivity rates to nickel, methylchloroisothiazolinone/methylisothiazolinone, and benzophenone-3. During the same period of study, there were significant decreases in positivity rates to neomycin, fragrance mix I, formaldehyde, thiuram mix, cinnamic aldehyde, propylene glycol, epoxy resin, diazolidinyl urea, amidoamine, ethylenediamine, benzocaine, p-tert-butylphenol formaldehyde resin, dimethylol dimethyl hydantoin, cocamidopropyl betaine, glutaraldehyde, mercaptobenzothiazole, tosylamide formaldehyde resin, budesonide, disperse blue 106, mercapto mix, and chloroxylenol. Twenty-four percent (1221) had a relevant positive reaction to a non-NACDG supplementary allergen; and 180 of these reactions were occupationally relevant., Conclusions: Periodic analysis, surveillance, and publication of multicenter study data sets document trends in allergen reactivity incidence assessed in the patch test clinic setting and provide information on new allergens of relevance.

Background: Contact dermatoses are common in food service workers (FSWs)., Objectives: This study aims to (1) determine the prevalence of occupationally related contact dermatitis among FSWs patch tested by the North American Contact Dermatitis Group (NACDG) and (2) characterize responsible allergens and irritants as well as sources., Methods: Cross-sectional analysis of patients patch tested by the NACDG, 1994 to 2010, was conducted., Results: Of 35,872 patients patch tested, 1237 (3.4%) were FSWs. Occupationally related skin disease was significantly more common in FSWs when compared with employed non-FSWs. Food service workers were significantly more likely to have hand (P < 0.0001) and arm (P < 0.0006) involvement. The rates for irritant and allergic contact dermatitis in FSWs were 30.6% and 54.7%, respectively. Although the final diagnosis of irritant contact dermatitis was statistically higher in FSWs as compared with non-FSWs, allergic contact dermatitis was lower in FSWs as compared with non-FSWs. The most frequent currently relevant and occupationally related allergens were thiuram mix (32.5%) and carba mix (28.9%). Gloves were the most common source of responsible allergens. The NACDG standard tray missed at least 1 occupationally related allergen in 38 patients (4.3%)., Conclusions: Among FSWs patch tested by the NACDG between 1994 and 2010, the most common allergens were thiuram mix and carba mix. Gloves were the most common source of responsible allergens.

Background: European studies document that occupational contact dermatitis (CD) is common in hairdressers, but studies from North America are lacking., Objectives: The objectives of this study were to estimate the prevalence of occupational CD among North American hairdressers/cosmetologists (HD/CS) and to characterize responsible allergens and irritants as well as their sources., Methods: A cross-sectional analysis of patients patch tested by the North American Contact Dermatitis Group between 1994 and 2010 was conducted., Results: Of 35,842 patients, 432 (1.2%) were HD/CS. Significantly, most of the HD/CS were female (89.8%) and younger than 40 years (55.6%) as compared with non-hairdressers (P < 0.0001). The rates for allergic and irritant CD in HD/CS were 72.7% and 37.0%, respectively. The most common body site of involvement was the hand, and this was significantly more common than in non-HD/CS (P < 0.0001). The most frequent currently relevant and occupationally related allergens were glyceryl thioglycolate, p-phenylenediamine, nickel sulfate, 2-hydroxyethyl methacrylate, and quaternium-15. Hair dyes, permanent wave solutions, and other hair products were common sources of allergens. The North American Contact Dermatitis Group allergen series missed at least 1 occupationally-related allergen in 26.2% of patients., Conclusions: Contact dermatitis in North American HD/CS is common, and occupationally related allergens are those found in HD/CS products. Supplemental hairdressing/cosmetology antigen series are important in detecting all occupationally related allergens in this population.

Atopic dermatitis (AD) in young children is often followed by the development of asthma (atopic march). The role of environmental exposures is unclear in this high-risk population. We aimed to determine the predictive relationship between indoor allergen exposures, particularly pets, rodents, and cockroaches, to the development of asthma in a prospective pediatric cohort. Children with AD and a family history of allergy were followed prospectively with questionnaire ascertainment of environmental exposure to cats, dogs, cockroaches, rats, and mice. Asthma was diagnosed by study physicians based on caregiver reports of symptoms continually assessed over the course of the study period. Fifty-five of the 299 children developed asthma by the end of the study. Cat exposure had a strong and independent effect to reduce the risk of developing asthma across all analyses (odds ratio [OR], 0.16; 95% confidence interval [CI], 0.05-0.53). Dog, mouse, rat, and cockroach exposures did not significantly influence the development of asthma. Daycare exposure had the largest risk reduction for the development of asthma (OR, 0.08; 95% CI, 0.03-0.19). Maternal asthma (OR, 2.93; 95% CI, 1.29-6.67), baseline body mass index (OR, 1.23; 95% CI, 1.08-1.42), and specific immunoglobulin E to house-dust mix at 3 years were each independent risk factors for the development of asthma. In children with AD, cat and daycare exposure may reduce the risk of developing early childhood asthma.

Background: Identification of putative contact allergen and source material is often done by a combination of patch testing and manufacturer-supplied product information. The accuracy of the identification of allergen-source material and level of allergen in that allergen-source material is not known., Objective: The objectives of the study were to survey the chemical allergen content of glove allergic contact dermatitis (ACD) patient-identified problem and nonproblem gloves and to evaluate the ability of the patient to discriminate between problem and nonproblem gloves., Methods: Gloves from patch-tested rubber allergen-positive ACD patients were analyzed for species and amount of rubber allergen., Results: Approximately half the subjects were able to correctly identify their problem and nonproblem gloves. Correct association of a glove with ACD was directly related to patch-test reaction severity and inversely related to the number of glove brands being used by the patient. Of note, thiurams were not detected in any of the gloves examined., Conclusions: Although patch testing is invaluable in identifying individual allergen sensitivities, the identification of the ACD-causative specific chemical allergen and source material remains problematic. All glove brands used within days prior to and during an ACD episode should be considered potential sources of the contact allergen.

Carvone has occasionally been reported as an allergen, usually in flavorings. Isomers of carvone have been either a mint or a rye flavor and aroma. We report a woman with positive patch-test reactions to carvone (newly added to the North American Contact Dermatitis Group standard series) and dermatitis on the head. She had used a hair conditioner with a "mint" scent, and the dermatitis resolved when she discontinued using this product. While the manufacturer would not confirm carvone as an ingredient, the clinical course, patch-test results, and ingredient list strongly suggest that this was a relevant allergen in this case of allergic contact dermatitis.

Background: The North American Contact Dermatitis Group (NACDG) tests patients who have suspected allergic contact dermatitis with a broad series of screening allergens, and publishes periodic reports of its data., Objective: To report the NACDG patch-test results from January 1, 2005, to December 31, 2006, and to compare results to pooled test data from the previous 10 years., Methods: Standardized patch testing with 65 allergens was used at 13 centers in North America. Chi-square statistics were utilized for comparisons with previous NACDG data., Results: NACDG patch-tested 4,454 patients; 12.3% (557) had an occupation-related skin condition, and 65.3% (2,907) had at least one allergic patch-test reaction. The 15 most frequently positive allergens were nickel sulfate (19.0%), Myroxilon pereirae (balsam of Peru, 11.9%), fragrance mix I (11.5%), quaternium-15 (10.3%), neomycin (10.0%), bacitracin (9.2%), formaldehyde (9.0%), cobalt chloride (8.4%), methyldibromoglutaronitrile/phenoxyethanol (5.8%), p-phenylenediamine (5.0%), potassium dichromate (4.8%), carba mix (3.9%), thiuram mix (3.9%), diazolidinylurea (3.7%), and 2-bromo-2-nitropropane-1,3-diol (3.4%). As compared to the 1994-2004 data, there were significant increases in rates of positivity to nickel, quaternium-15, potassium dichromate, lidocaine, and tea tree oil. Of patch-tested patients, 22.9% (1,019) had a relevant positive reaction to a supplementary allergen; 4.9% (219) had an occupationally relevant positive reaction to a supplementary allergen., Conclusion: Nickel has been the most frequently positive allergen detected by the NACDG; rates significantly increased in the current study period and most reactions were clinically relevant. Other common allergens were topical antibiotics, preservatives, fragrance mix I and paraphenylenediamine. Testing with an expanded allergen series and supplementary allergens enhances detection of relevant positive allergens.

Objectives: To determine the frequency of positive and relevant patch tests in children referred for patch testing in North America; to compare results of patch testing children and adults; and to compare our results with international data on contact allergy in children., Design: Retrospective cross-sectional analyses of North American Contact Dermatitis Group (NACDG) data from January 1, 2001, through December 31, 2004. Patch test reactions for allergens that were positive and considered of clinical importance to the patient's eczematous problem were defined as being of current or past relevance., Setting: Clinical patch test data from 13 NACDG members, primarily a referral population., Patients: The pediatric population (hereafter referred to as "children") was defined as patients aged 0 to 18 years (n = 391). Patients 19 years and older constituted the comparison adult group (n = 9670)., Main Outcome Measures: The frequency of positive patch test reactions and number of relevant ones. Secondary measures included the association of atopic markers, frequency of irritant reactions, and sources of relevant supplementary allergens., Results: No significant difference in the overall frequency of at least 1 relevant positive patch test reaction was noted in children (51.2%) compared with adults (54.1%). The most frequent positive reactions in children were to nickel (28.3%), cobalt chloride (17.9%), thimerosal (15.3%), neomycin sulfate (8.0%), gold sodium thiosulfate (7.7%), and fragrance mix (5.1%). For children aged 0 to 18 the most frequent relevant positive reactions were to nickel sulfate (26.0%), cobalt (12.4%), neomycin (4.4%), fragrance mix (4.1%), gold (3.6%), and quaternium 15 (3.6%). The frequency of irritant reactions in adults and children was similar. Of the children with a relevant positive reaction, 34.0% had atopic dermatitis included as one of their final diagnoses, compared with 11.2% of adults (P < .001). Fifteen percent and 39% of children had relevant allergens not included in the NACDG series and a commercially available skin patch test (T.R.U.E. TEST [thin-layer rapid use epicutaneous test], panel 1.1 and 2.1; Allerderm, Phoenix, Arizona), respectively., Conclusions: Adults and children in this group are equally likely to have allergic contact dermatitis; frequency of relevant allergen reactions differs.

Background: Allergic and irritant contact dermatitis to food is likely underreported., Objectives: To characterize relevant allergens and irritants associated with food in patients referred to the North American Contact Dermatitis Group (NACDG) for patch testing., Methods: Retrospective analysis of cross-sectional data from the NACDG from 2001 to 2004., Results: Of 10,061 patch-tested patients, 109 (1.1%) had a total of 122 reactions associated with food. Approximately two-thirds of patients (66%) were female, and one-third (36%) were atopic. The hands were the most common sites of dermatitis (36.7%). There were 78 currently relevant (definite, probable, or possible) allergic reactions to NACDG standard series allergens with a food source; the most common allergen was nickel (48.7%), followed by Myroxilon pereirae (balsam of Peru) (20.6%) and propylene glycol (6.4%). Twenty allergic reactions to non-NACDG standard allergens and 24 relevant food irritants were also identified. Overall, 21% (25 of 122) of all reactions (irritant and allergic) were occupation related; the majority of these (17 of 25) were relevant irritant reactions. Cooks were the most commonly affected occupational group (40%)., Conclusions: In this limited data set, nickel, Myroxilon pereirae, and propylene glycol were the most common allergens identified with a food source. Of food-related occupational disease, irritation was more common than allergy.

Background: A scattered generalized distribution (SGD) of dermatitis is a challenging problem; patch testing is a strategy for evaluating allergic contact dermatitis as a relevant factor., Objective: We sought to analyze patient characteristics and most frequently relevant positive allergens in patients presenting for patch testing with SGD., Methods: We conducted retrospective cross-sectional analysis of North American Contact Dermatitis Group 2001 to 2004 data. Patients with SGD were compared with patients without SGD., Results: Of 10,061 patients, 14.9% (n = 1497) had only a SGD. Men and patients with a history of atopic eczema were more likely to have dermatitis in a SGD (P < .001). Preservatives, fragrances, propylene glycol, cocamidopropyl betaine, ethyleneurea melamine formaldehyde, tixocortol pivalate, and budesonide were among the more frequently relevant positive allergens. Top allergen sources included cosmetics/beauty preparations/skin and health care products, clothing, and topical corticoids., Limitations: This was a retrospective analysis of patch-tested patients with SGD suspected to have allergy., Conclusions: A total of 49% of patients with SGD had at least one relevant positive allergen, thus demonstrating the benefit of patch testing these patients.

Background: Contact dermatoses are common in health care workers (HCWs)., Objectives: To (1) estimate the prevalence of occupation-relevant allergic contact dermatitis (ACD) among health care workers patch-tested from 1998 to 2004 by the North American Contact Dermatitis Group (NACDG), (2) characterize responsible allergens among health care workers overall as well as in specific health care occupational subgroups, and (3) compare these results to those of nonhealth care workers., Methods: Between 1998 and 2004, 15,896 patients were patch-tested by the NACDG. Occupation-related allergic patch-test results were analyzed among HCWs, subgroups of HCWs, and non-HCWs., Results: 1,255 patients (7.9%) were HCWs. Female gender (HCWs, 86.2%; non-HCWs, 63.6%) and hand involvement (HCWs, 54.7%; non-HCWs, 27.8%) were more common in HCWs (p < .05); 18.2% of HCWs and 6.6% of non-HCWs had occupation-related allergens of current clinical relevance. Thiuram mix (HCWs, 8.87% non-HCWs, 0.90%) and carba mix (HCWs, 5.43%; non-HCWs, 0.87%) were the most common occupation-related currently relevant antigens in HCWs and were more common in HCWs than in non-HCWs (p < .05)., Conclusions: Among HCWs patch-tested by the NACDG between 1998 and 2004, the most common allergens were thiuram mix and carba mix, followed by glutaraldehyde, cocamide diethanolamine, and chloroxylenol. Gloves, sterilizing solutions, and soaps were common sources of responsible allergens.

Background: The most common differential diagnoses for patients presenting with lip dermatitis or inflammation include atopic, allergic, and irritant contact dermatitis. Patch testing can be performed to identify the allergic contact conditions., Objective: To report North American Contact Dermatitis Group (NACDG) patch-test results of patients who presented for patch testing with only lip involvement from 2001 to 2004. Patient characteristics, allergen frequencies, relevance, final diagnoses, and relevant allergic sources not in the NACDG screening series were evaluated., Methods: The NACDG 2001-2004 database was used to select patients presenting with only lip involvement., Results: Of 10,061 patients tested, 2% (n = 196) had lips as the sole involved site. Most (84.2%) were women. After patch testing, 38.3% (n = 75) were diagnosed with allergic contact cheilitis. Fragrance mix, Myroxilon pereirae, and nickel were the most common relevant allergens. Of 75 patients, 27 (36%) had relevant positive patch-test reactions to items not on the NACDG series; lipstick and cosmetics were the predominant sources., Conclusions: Patch testing is valuable in the evaluation and identification of contact allergy in patients referred for lip dermatitis. The use of supplementary allergens based on history and exposure is important in the identification of additional relevant allergens. Over a third of patients with contact allergy had other factors, such as irritant dermatitis, considered relevant to their condition.

Background: Allergic contact dermatitis is a significant cause of both occupational and non-occupational skin disease. Patch testing is an important diagnostic tool for the determination of responsible allergens., Objective: This study reports the results of patch testing by the North American Contact Dermatitis Group from January 1, 2003, to December 31, 2004., Methods: At 13 centers in North America, patients were tested with the same screening series of 65 allergens, with a standardized patch-testing technique. Data were recorded on standardized forms and manually verified and entered. Descriptive frequencies were calculated, and trends were analyzed with chi-square statistics., Results: A total of 5,148 patients were tested. Of these, 3,432 (66.7%) had at least one positive reaction, 2,284 (44.4%) were ultimately determined to have primary allergic contact dermatitis, and 676 (13.1%) had occupation-related skin disease. There were 9,762 positive allergic reactions. Compared to the previous reporting period (2001-2002), allergies to nickel, budesonide, mercaptobenzothiazole, and paraben mix were at least 1.12 times more common (all p values < .03). Compared with the previous 8 years (1994-2002), only the prevalence rates of allergies to nickel and budesonide were statistically significantly higher (p values < .003)., Conclusion: Allergic contact dermatitis from nickel and budesonide may be increasing in North America. These results again underscore the value of patch-testing with many allergens.

Background: Chemicals used in leather tanning, rubber processing, and/or adhesives are the most often-cited culprits in footwear dermatitis. Patch testing patients with suspected shoe dermatitis is essential for diagnosis and management., Objectives: The four goals for this study were to (1) determine the frequency of allergens associated with a shoe source in North American Contact Dermatitis Group (NACDG) patients with footwear allergic contact dermatitis; (2) compare these results to allergen frequencies from other published studies; (3) quantify the number of shoe-related reactions that were not identified with the NACDG standard series; and (4) identify relevant allergens not included on the NACDG standard series, based on data from other published studies., Methods: The NACDG patch-tested 10,061 patients between 2001 and 2004. Data were retrospectively analyzed by (1) allergen source coded as "shoe," (2) site of dermatitis as "feet," and (3) diagnosis of "allergic contact dermatitis.", Results: Among the 109 NACDG patients with allergic contact dermatitis (ACD) of the foot and a shoe source of allergens, p-tertiary butylphenol formaldehyde resin, an adhesive, was the most common allergen, accounting for 24.7% of positive patch-test results, followed by potassium dichromate (17.5%) and carba mix (11.7%). When the data were examined according to groups of allergens, rubber chemicals (40.4%) were the most frequent allergens, followed by adhesives (32.5%), and leather components (20.1%). When data from published studies were pooled, potassium dichromate (31.5%) was the most frequent allergen, followed by p-tertiary butylphenol formaldehyde resin (17.1%) and cobalt chloride (12.9%). NACDG patients were statistically more likely to have positive patch-test reactions to p-tertiary butylphenol formaldehyde resin and statistically less likely to have a positive patch-test reaction to potassium dichromate than patients represented in pooled data from past studies. Nineteen (17.4%) of the 109 NACDG patients with ACD of the foot and a shoe source of allergens were identified as having a shoe source of a relevant allergen not included in the NACDG standard series., Conclusions: In NACDG patients, the most common individual shoe allergen was p-tertiary butylphenol formaldehyde resin. As a group, rubber chemicals were most common, a finding consistent with those of other studies.

Background: The low concentration of propylene glycol (PG) in pimecrolimus cream makes it unlikely that the cream will induce a PG-related irritant or allergic contact dermatitis., Objective: To assess reactions to pimecrolimus cream in patients who are allergic to PG., Methods: A pilot double-blind within-patient study in 20 patients, with patch testing followed by a repeated open application test (ROAT). Limitations were that patch tests and ROATs were performed on normal skin, which may be less likely to develop an allergic response than would areas of active dermatitis., Results: Positive PG patch-test results were confirmed in 16 patients. Patch-test scores were compatible with allergic reactions in only two patients. However, ROAT scores were negative for these two patients. Reactions with pimecrolimus or vehicle during ROAT were identified in three patients, but an allergic reaction was uncertain because none of these patients reacted with both pimecrolimus cream and vehicle. Reactions with pimecrolimus were significantly less frequent (p<.01) and less severe (p=.02) than with PG., Conclusion: In patients allergic to PG, pimecrolimus cream showed a very low potential to elicit allergic skin reactions.

Objective: To determine whether petrolatum or aqueous vehicles are more sensitive for detecting allergy to imidazolidinylurea (IU), diazolidinylurea (DU), and dimethylol dimethyl hydantoin (DM). The relationship of these allergens to formaldehyde sensitivity was also explored., Methods: Retrospective analysis of patients patch-tested by the North American Contact Dermatitis Group. All patients were simultaneously tested to seven allergens (formaldehyde, IU in petrolatum [pet], IU aqueous [aq], DU pet, DU aq, DM pet, and DM aq). Data were analyzed in pairs with various "gold standard" definitions of "true allergy" and adjusting for correlated data., Results: Reaction to at least one of the seven allergens occurred in 2,398 patients. In all cases except one (which just approached statistical significance), the petrolatum-based allergen was statistically significantly more sensitive than the same allergen in an aqueous base. Most of the patients allergic to the three preservatives were also allergic to formaldehyde, but most formaldehyde-allergic patients were not allergic to the IU, DU, or DM., Conclusion: Of these two vehicles, petrolatum is significantly more sensitive than an aqueous vehicle is for detecting allergy to IU, DU, and DM.

Cobalt is a common inducer of allergic contact dermatitis. A new jewelry alloy containing cobalt was developed and tested on 30 individuals with documented allergy to cobalt. Of these subjects, 5 (18%) were found to be allergic to the new alloy after 7 or 8 days of exposure. In all cases, the reaction was much less severe than allergy to the 1% cobalt chloride patch test material. This new alloy should be better tolerated by individuals allergic to cobalt, perhaps because the cobalt is tightly bound in the alloy by the other main component, platinum.

Background: Allergic contact dermatitis is a significant cause of cutaneous disease affecting many individuals in the home and at the workplace. Patch testing is the most worthwhile diagnostic tool for the evaluation of patients with suspected allergic contact dermatitis., Objective: This study reports the results of patch testing from January 1, 2001, to December 31, 2002, by the North American Contact Dermatitis Group (NACDG)., Methods: Patients were tested with an extended screening series of 65 allergens. A standardized patch-testing technique was used. Data from these patients were recorded on a standardized computer entry form and analyzed., Results: Sixty-five allergens were tested on 4,913 patients. The top 10 allergens remain the same in this study period as in the 1999-2000 study period: nickel sulfate (16.7%), neomycin (11.6%), Myroxilon pereirae (balsam of Peru) (11.6%), fragrance mix (10.4%), thimerosal (10.2%), sodium gold thiosulfate (10.2%), quaternium-15 (9.3%), formaldehyde (8.4%), bacitracin (7.9%), and cobalt chloride (7.4%). Of the 4,913 patients tested, 69% had at least one positive allergic patch-test reaction. Of all patients, 15.8% had occupation-related dermatitis; 15.4% were determined to have irritant contact dermatitis, and 11.1% of the 15.4% had a relevant reaction to an occupational irritant. Of all patients tested, 16.7% had a relevant reaction to an allergen not in the NACDG standard series, and 5.5% had a relevant reaction to an occupational allergen not in the standard series., Conclusion: Our findings once again reinforce the need for a more comprehensive group of diagnostic allergens than those found in the standard screening kits. The usefulness of patch testing is enhanced when a greater number of allergens are tested, especially nonstandard allergens occupationally encountered.

Background: The prevalence of allergy to cocamidopropyl betaine (CAPB) in North America has not been previously reported., Objective: The aim of this study was to report on the most recent data on allergy to CAPB and a related allergen, amidoamine (AA)., Methods: Data was collected by the North American Contact Dermatitis Group from consecutive patients presenting for patch testing for diagnosis of presumed allergic contact dermatitis (ACD) from January 1, 2001, through December 31, 2001., Results: Of 975 patients tested, 15 were patch-test positive to CAPB, 25 had positive reactions to AA, and 18 had positive reactions to both CAPB and AA. The most frequent site of dermatitis from CAPB was the head and neck region., Conclusion: In North America, both CAPB and AA are useful allergens for detecting ACD.

Background: Cocamidopropyl betaine (CAPB) is a surfactant, primarily used in personal cleansing products, that may cause allergic contact dermatitis (ACD). Amidoamine (AA), a by-product and a known contaminant in CAPB synthesis, may be the true allergen responsible for some cases of CAPB allergy. Co-reactivity with these allergens and cocamide diethanolamine (CDEA) and formaldehyde has been noted anecdotally., Objective: This study investigated (1) the correlation and clinical relevance of positive patch-test reactions to CAPB and AA in cases of ACD and (2) the rate of positive reactions to CDEA and formaldehyde in these patients., Methods: Patients with patch-test reactions to either CAPB or AA during 2001 were retrospectively identified. Relevance of reactions to CAPB and AA was then graded as definite, probable, or not relevant, based on patient follow-up. The proportion of these patients who also had positive reactions to CDEA or formaldehyde was noted., Results: Of 957 patch-tested patients, 49 had positive reactions to either CAPB (42.9%) or AA (34.3%) or to both (22.8%). Of these patients, 35 were available for follow-up. Twenty-nine (83.0%) of these patients identified the surfactant in their home products. In all of these patients, the dermatitis was felt to be due in whole or in part to CAPB exposure. Two patients (5.7%) had a positive reaction to CDEA, and 8 patients (23%) had a positive reaction to formaldehyde., Conclusion: Patch testing with both CAPB and AA identifies patients with ACD relevant to exposure to CAPB. Since few patients react to both allergens, testing with both separately is useful. Formaldehyde allergy was overrepresented in CAPB-allergic patients in this series of patients.

Background: Patch testing is the most worthwhile diagnostic tool for the evaluation of patients with suspected allergic contact dermatitis., Objective: This study reports patch-testing results from July 1, 1998, to December 31, 2000, by the North American Contact Dermatitis Group., Methods: Patients were tested with the same screening series of allergens, using a standardized patch-testing technique. The data from these patients were recorded on a standard computer entry form and analyzed., Results: Fifty allergens were tested on over 5,800 patients. Amidoamine, benzophenone-3, and iodopropynyl butylcarbamate were the new allergens. The top 10 allergens in frequency of positive reactions were identical to those of our 1996-to 1998-study period. The incidence of allergic nickel reactions continues to go up, leading all the test substances by 16.2%., Conclusion: Our findings reinforce the need for a more comprehensive group of diagnostic allergens than is found in the T.R.U.E. TEST, which is sold in the United States.

Background: Both irritant and allergic contact dermatitis can be influenced by occupational and nonoccupational environmental exposures., Objective: The aim of this study is to compare the occupations and allergens of occupational contact dermatitis cases with nonoccupational contact dermatitis cases., Methods: Diagnostic patch testing was conducted with the 50 screening allergens of the North American Contact Dermatitis Group and occupational coding by the Surveillance Branch of the National Institute of Occupational Safety and Health., Results: Of the 5,839 patients patch tested for contact dermatitis, 1,097 (19%) were deemed to be occupationally related. Of the occupational cases, 60% were of allergic and 32% were of irritant origin. The hands were the primary body part affected in 64% of allergic occupational cases and 80% of irritant occupational cases. Epoxy resin was the only allergen tested that was associated more with an occupational exposure than nonoccupational exposure. The allergens encountered most frequently in the occupational cases were carba mix, thiuram mix, epoxy resin, formaldehyde, and nickel. The medical field is overrepresented in the data compared with other occupations., Conclusions: Occupational contact dermatitis frequently was found to be multifactorial and associated with several specific allergens and occupations., (Copyright 2002, Elsevier Science (USA))