Allergic or Not: Final Interpretation of Doubtful Patch Test Reactions From the North American Contact Dermatitis Group, 2019-2020

Background: Doubtful patch test reactions generally do not meet criterion for positivity in patch testing. However, the North American Contact Dermatitis Group (NACDG) allows for doubtful reactions to be coded with a final determination of "allergic/positive" based on the temporal pattern, appearance, known characteristics of the allergen, and/or other supportive patch test reactions. Objectives: To analyze NACDG data from the 2019-2020 patch test cycle to identify patterns in the interpretation and relevance of doubtful reactions. Methods: The frequency and proportions of doubtful reactions were tabulated and analyzed for patterns. Statistical analyses were limited to allergens with ≥30 doubtful reactions to ensure adequate sample size. Results: Of patch-tested patients, 31.9% (1315/4121) had ≥1 doubtful reaction. Of 2538 total doubtful reactions, 46% (n = 1167) had a final interpretation of "allergic/positive." The allergens with the highest proportion of doubtful reactions at the final visit were hydroperoxides of linalool 1% (4.5%), fragrance mix I 8.0% (3.9%), and cetrimonium chloride 0.5% (3.4%). Methylchloroisothiazolinone/methylisothiazolinone (MCI/MI) 0.02% (P < 0.001), MI 0.2% (P < 0.001), nickel sulfate hexahydrate 2.5% (P = 0.001), and neomycin sulfate 20.0% (P = 0.003) doubtful reactions were more likely to be interpreted as allergic than nonallergic. Methyldibromoglutaronitrile/phenoxyethanol 0.2% (P < 0.001), oleamidopropyl dimethylamine 0.1% (P < 0.001), formaldehyde 2.0% (P < 0.001), cetrimonium chloride 0.5% (P < 0.001), benzophenone-4 (sulisobenzone) 10% (P < 0.001), iodopropynyl butylcarbamate 0.5% (P < 0.001), cocamidopropyl betaine 1.0% (P = 0.002), and benzisothiazolinone 0.1% (P = 0.012) doubtful reactions were less likely to be interpreted as allergic. Of the 1167 doubtful reactions interpreted as allergic, 84.9% had current relevance. Conclusions: Doubtful reactions were common and approximately one half were coded with a final interpretation of "allergic/positive." Of those, most were clinically relevant. MCI/MI, MI, nickel, and neomycin were more likely to be interpreted as allergic.

Patch Testing With Nickel, Cobalt, and Chromium in Patients With Suspected Allergic Contact Dermatitis

Background: Allergic contact dermatitis is frequently caused by metals, including multiple metals simultaneously. Objectives: To assess characteristics and associations of positive and clinically relevant patch test (PT) reactions with solitary and concurrent metal sensitization. Methods: A retrospective analysis of PT results for nickel, cobalt, and/or chromium from the North American Contact Dermatitis Group between 2001 and 2018 (n = 43,522). Results: 18.0% had a positive/allergic reaction to nickel sulfate hexahydrate, 7.3% to cobalt chloride hexahydrate, and 3.0% to potassium dichromate. 87.9% patients had a currently relevant reaction to 0, 9.4% to 1, and 2.7% to multiple metals tested. Patients with 1 versus no currently relevant reactions to metal were more likely to have a primary dermatitis site of trunk, feet, and ears; patients with currently relevant reactions to multiple metals had more dermatitis affecting the trunk and ears. Metal sources varied by co-reacting metal, especially for patients with cobalt and chromium allergy. Jewelry was the most commonly identified source of nickel and cobalt for both solitary and concurrent metal allergy. Conclusions: Sensitization to multiple metals occurred in 6% of patients. Allergen sources varied between patients with sensitivity to 1 metal versus those who had concurrent sensitivity to cobalt and/or chromium.

More than just methylisothiazolinone: Retrospective analysis of patients with isothiazolinone allergy in North America, 2017-2020

BACKGROUND

Isothiazolinones are a common cause of allergic contact dermatitis.

OBJECTIVE

To examine the prevalence of positive patch test reactions to isothiazolinones from 2017-2020 and characterize isothiazolinone-allergic (Is+) patients compared with isothiazolinone nonallergic (Is-) patients.

METHODS

Retrospective cross-sectional analysis of 9028 patients patch tested to methylchloroisothiazolinone (MCI)/methylisothiazolinone (MI) 0.02% aqueous, MI 0.2% aqueous, benzisothiazolinone (BIT) 0.1% petrolatum, and/or octylisothiazolinone (OIT) 0.025% petrolatum. Prevalence, reaction strength, concurrent reactions, clinical relevance, and source of allergens were tabulated.

RESULTS

In total, 21.9% (1976/9028) of patients had a positive reaction to 1 or more isothiazolinones. Positivity to MI was 14.4% (1296/9012), MCI/MI was 10.0% (903/9017), BIT was 8.6% (777/9018), and OIT was 05% (49/9028). Compared with Is-, Is+ patients were more likely to have occupational skin disease (16.5% vs 10.3%, P <.001), primary hand dermatitis (30.2% vs 19.7%, P <.001), and be >40 years (73.1% vs 61.9%, P <.001). Positive patch test reactions to >1 isothiazolinone occurred in 44.1% (871/1976) of Is+ patients. Testing solely to MCI/MI would miss 47.3% (611/1292) of MI and 60.1% (466/776) of BIT allergic reactions.

LIMITATIONS

Retrospective cross-sectional study design and lack of follow-up data.

CONCLUSION

Sensitization to isothiazolinones is high and concurrent sensitization to multiple isothiazolinone allergens is common.

Patch Testing to Chlorhexidine Digluconate, 1% Aqueous: North American Contact Dermatitis Group Experience, 2015-2020

Background: Chlorhexidine is an antiseptic that may cause allergic contact dermatitis. Objectives: To describe the epidemiology of chlorhexidine allergy and characterize positive patch test reactions. Methods: This retrospective study analyzed patients patch tested to chlorhexidine digluconate 1% aqueous by the North American Contact Dermatitis Group, 2015-2020. Results: Of 14,731 patients tested to chlorhexidine digluconate, 107 (0.7%) had an allergic reaction; of these, 56 (52.3%) reactions were currently clinically relevant. Most (59%) reactions were mild (+), followed by strong (++, 18.7%) and very strong (+++, 6.5%). Common primary dermatitis anatomic sites in chlorhexidine-positive patients were hands (26.4%), face (24.5%), and scattered/generalized distribution (17.9%). Compared with negative patients, chlorhexidine-positive patients were significantly more likely to have dermatitis involving the trunk (11.3% vs 5.1%; P = 0.0036). The most commonly identified source category was skin/health care products (n = 41, 38.3%). Only 11 (10.3%) chlorhexidine reactions were occupationally related; of these, 81.8% were in health care workers. Conclusions: Chlorhexidine digluconate allergy is uncommon, but often clinically relevant. Involvement of the hands, face, and scattered generalized patterns was frequent. Occupationally related reactions were found predominantly in health care workers.

Patch Testing to Paraphenylenediamine: The North American Contact Dermatitis Group Experience (1994-2018)

Background/Objectives: Paraphenylenediamine (PPD) is an aromatic amine dye that may cause allergic contact dermatitis. This study examines the epidemiology of allergic patch test reactions to PPD. Methods: This retrospective analysis characterizes individuals tested to PPD (1% petrolatum) by the North American Contact Dermatitis Group (1994-2018). Demographics and dermatitis site(s) were compared between PPD-allergic and PPD-negative patients. PPD reactions were analyzed by reaction strength, clinical relevance, occupational relatedness, and source as well as coreactivity with structurally related compounds. Results: Of 54,917 patients tested to PPD, 3095 (5.6%) had an allergic patch test reaction. Compared with PPD-negative patients, PPD-allergic patients had significantly greater odds of age >40 years (odds ratio [OR] 1.55 [95% confidence interval; CI 1.43-1.69]) and female gender (OR 1.52 [95% CI 1.41-1.66]), but lower odds of being White (OR 0.66 [95% CI 0.60-0.71]). The most common primary anatomic sites of dermatitis were face (25.5%), hands (21.9%), and scattered/generalized pattern (15.5%). Over half (55.3%) of PPD reactions were ++ or +++ at the final reading and 60.9% were currently relevant. Common exposure sources included hair dye (73.5%) and clothing/shoes/apparel (3.9%). Occupationally related reactions occurred in 8.3%, most commonly in hairdressers/cosmetologists (72.8%). The most common coreactions were benzocaine (11.3%), N-isopropyl-N'-phenyl-p-phenylenediamine (6.7%), disperse dye mix (6.5%), and black rubber mix (5.1%). Conclusions: The 24-year percentage of allergic reactions to PPD was 5.6%. PPD allergy was associated with female gender and age >40 years. PPD allergic patients were less likely to be White. Allergic reactions were usually clinically relevant and hair dye was the most frequently identified source.

Patch Test Results Among Older Adults: A Retrospective Analysis of the North American Contact Dermatitis Group Data (2009-2020)

Background: Allergic contact dermatitis (ACD) in older adults (OA) represents a significant health burden, but few studies examine the prevalence and characteristics of contact allergy and ACD in this population. Objective: To compare positive and clinically relevant patch test results in OA versus younger adults (YA) and children. Methods: Retrospective analysis of patch test results obtained in OA (≥65 years), YA (19-64 years), and children (≤18 years) by the North American Contact Dermatitis Group, 2009 to 2020. Results: Of 28,177 patients patch tested, 5366 (19.0%) were OA. OA were more likely to have a final primary diagnosis of ACD as compared with YA (50.8% vs 49.2%, P = 0.035) and children (44.6%, P < 0.0001). The primary site of dermatitis also differed by age group, with OA having a higher proportion of dermatitis affecting the trunk, scalp, anogenital region, and "under clothing," and a lower proportion of dermatitis affecting the face, lips, and feet. Limitations: Retrospective design, lack of follow-up, and referral population. Conclusion: OA were as likely and were statistically even more likely to have a final primary diagnosis of ACD compared with YA and children. Anatomic site of dermatitis also differed by age group. This underscores the need for patch testing in OA when ACD is suspected.

Patch Testing With Cobalt in Adults: A North American Contact Dermatitis Group Experience, 2001-2018

Background: Cobalt is a recognized cause of allergic contact dermatitis (ACD); however, detailed information on patient characteristics, sites, and sources is lacking. Objective: The aim of the study is to assess trends in patch test reactions to cobalt and associated patient characteristics, common sources, and body sites affected. Methods: The study used a retrospective analysis of adult patients who were patch tested to cobalt by the North American Contact Dermatitis Group between 2001 and 2018 (n = 41,730). Results: Overall, 2986 (7.2%) and 1362 (3.3%) had allergic or currently relevant patch test reaction to cobalt, respectively. Patients with versus without an allergic patch test reaction to cobalt were more likely to be female, employed, have a history of eczema or asthma, be Black, Hispanic, or Asian, and have occupational-related dermatitis. The most commonly identified sources of cobalt in allergic patients included jewelry, belts, and cement, concrete, and mortar. Affected body site(s) varied by cobalt source among patients with currently relevant reactions. Occupational relevance was found in 16.9% of patients with positive reactions. Conclusions: Positive patch test reactions to cobalt were common. The most common body sites were the hands, and affected site varied by the source of cobalt.

Prevalence and trend of allergen sensitization in patients with cheilitis referred for patch testing, North American Contact Dermatitis Group data, 2001-2018

BACKGROUND

An updated understanding of allergic contact cheilitis is needed.

OBJECTIVES

To characterize clinical characteristics and allergen relevance in patients with cheilitis referred for patch testing.

METHODS

Retrospective analysis of 43 772 patients patch tested with the North American Contact Dermatitis Group (NACDG) screening series from 2001 to 2018.

RESULTS

Overall, 2094 patients (4.8%) had lips as one of three sites of dermatitis, 1583 (3.6%) had lips as the primary site and 1167 (2.7%) had lips as the sole site of dermatitis. Prevalences of cheilitis at any, primary, and sole sites significantly increased throughout the study cycle from 2001-2002 (2.7%, 2.2% and 1.7%) to 2017-2018 (7.8%, 5.2% and 3.7%). Approximately 60% of patients with any, a primary, or a sole site of cheilitis had one or more positive allergic patch-test reactions compared to 65% of those without cheilitis.

CONCLUSION

Patients with cheilitis who were referred for patch testing had high rates of positive and relevant allergens. More than one in four patients with any, primary, or sole cheilitis had a positive reaction to non-NACDG screening allergens (28.0%, 26.8%, 31.1% vs. 21.6%) compared to patients without cheilitis, emphasizing the need for expanded patch test series in cheilitis.

North American Contact Dermatitis Group Patch Test Results: 2019-2020

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, 2019, to December 31, 2020. Methods: At 13 centers in North America, patients were tested in a standardized manner with a screening series of 80 allergens, and, as indicated, supplemental allergens. Results: Overall, 4121 patients were tested; 2871 (69.7%) had at least 1 positive/allergic patch test reaction and 2095 patients (51.2%) had a primary diagnosis of ACD. The most commonly positive allergens were nickel (18.2%), methylisothiazolinone (MI) (13.8%), fragrance mix (FM) I (12.8%), hydroperoxides of linalool (HPL) (11.1%), and benzisothiazolinone (BIT) (10.4%). Compared with that of 2017-2018, prevalence of top 20 allergens statistically increased for FM I, HPL, BIT, propolis, and hydroperoxides of limonene (3.5%). For the first time, MI positivity did not increase between reporting periods. Approximately one-fifth of patients (20.3%) had ≥1 clinically relevant reaction(s) to allergens/substances not on the NACDG series. Conclusions: The epidemic of MI contact allergy in North America may have reached a plateau. Patch testing using a robust screening series, and supplemental allergens as indicated, is necessary for comprehensive evaluation of ACD.

Trends in the Prevalence of Methylchloroisothiazolinone/Methylisothiazolinone Contact Allergy in North America and Europe

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.

Patch Testing With Benzophenone-3 and -4: The North American Contact Dermatitis Group Experience, 2013-2020

Background: Benzophenone (BZP)-3 and BZP-4 are ultraviolet (UV) absorbers used in sunscreens and personal care products (PCPs) and may cause allergic contact dermatitis. Objective: To characterize positive patch test reactions to BZP-3 (10% in petrolatum [pet]) and BZP-4 (2% pet) in a screening allergen series. Methods: Retrospective analysis of patients tested to BZP-3 and BZP-4 was conducted by the North American Contact Dermatitis Group from 2013 to 2020. Results: Of 19,618 patients patch tested to BZP-3 and BZP-4, 103 (0.5%) and 323 (1.6%) had positive reactions, respectively: 413 (2.1%) reacted to at least 1 BZP (BZP-positive patient). As compared with BZP-negative patients, BZP-positive patients were significantly more likely to have a history of hay fever (39.3% vs 33.4%, P = 0.0134), history of atopic dermatitis (39.8% vs 30.7%, P = 0.0001), and facial involvement (37.4% vs 32.2%, P = 0.0272). Most reactions were currently clinically relevant (BZP-3: 90.4%; BZP-4: 65.8%). Common identified sources included PCPs and sunscreens. Coreactivity between BZP-3 and BZP-4 was low: 13.5% (14/104) of BZP-3-positive patients were allergic to BZP-4 and 4.3% (14/322) of BZP-4-positive patients were allergic to BZP-3. Conclusions: Eight-year prevalence of BZP positivity was 2.1%. Reactions were frequently clinically relevant and linked to PCPs and sunscreens.

Patch testing with Cobalt in Children and Adolescents: North American Contact Dermatitis Group experience, 2001 to 2018

BACKGROUND

Allergic contact dermatitis (ACD) to cobalt is more common in children and adolescents than adults. However, detailed information on sites and sources of cobalt ACD are limited.

OBJECTIVES

To assess trends in positive and clinically relevant patch test reactions to cobalt in children and associated patient characteristics, common sources, and body sites affected.

METHODS

A retrospective analysis of children (<18 years) patch tested to cobalt by the North American Contact Dermatitis Group between 2001-2018.

RESULTS

Of 1,919 children patch tested, 228 (11.9%) and 127 (6.6%) had a positive/allergic or currently relevant patch test reaction to cobalt, respectively. The most common primary body sites affected were scattered generalized (30.0%), face, not otherwise specified (NOS, 10.6%), and trunk (10.1%). Patients with allergic and currently relevant allergic patch test reactions were more likely to have a primary site of trunk (P=.0160 and P=.0008) ears (P=.0005 and P<.0001). Affected body site(s) varied by cobalt source among patients with currently relevant reactions, especially for less common sources. The most commonly identified sources of cobalt included jewelry, belts, and clothing.

CONCLUSIONS

Positive patch test reactions to cobalt were common in children. Most common body site was scattered generalized and the sources of cobalt varied by body site. This article is protected by copyright. All rights reserved.

Patch testing with glucosides: The North American Contact Dermatitis Group experience, 2009-2018

BACKGROUND

Alkyl glucosides are nonionic surfactants that are increasingly used in personal care products.

OBJECTIVE

To characterize positive patch test reactions to decyl glucoside (5% petrolatum, tested 2009-2018) and lauryl glucoside (3% petrolatum, tested 2017-2018).

METHODS

Retrospective analysis of patients tested by the North American Contact Dermatitis Group.

RESULTS

Of 24,097 patients patch tested to decyl and/or lauryl glucoside, 470 (2.0%) had positive reactions. Compared with glucoside-negative patients, glucoside-positive patients had higher odds of occupational skin disease (13.4% vs 10.1%; P = .0207), history of hay fever (38.5% vs 31.6%; P = .0014), atopic dermatitis (39.0% vs 28.6%; P < .0001), and/or asthma (21.8% vs 16.5%; P = .0023). Most glucoside reactions (83.9%) were currently relevant. The most common source was personal care products (63.0%), especially hair products (16.5%) and skin cleansers (15.2%). Of 4933 patients tested to decyl and lauryl glucoside, 134 (2.7%) were positive to 1 or both; 43.4% (43 of 99) of decyl-positive patients were also positive to lauryl glucoside and 55.1% (43/78) of lauryl glucoside patients were also positive to decyl glucoside.

LIMITATIONS

The cohort predominantly reflects a referral population, and follow-up after testing was not captured.

CONCLUSION

Glucoside positivity occurred in 2.0% of the tested patients. Reactions were often clinically relevant and linked to personal care products. Cross-reactivity was >40%.

Medical Adhesive Allergens: Retrospective Analysis of Cross-Sectional Data from the North American Contact Dermatitis Group, 2001-2018

BACKGROUND

Identification of allergens causing medical adhesive contact allergy is difficult.

OBJECTIVE

Characterize the demographics, clinical characteristics, patch test results and occupational data for North American Contact Dermatitis Group (NACDG) patients with medical adhesive contact allergy.

METHODS

Retrospective study of 43,722 NACDG patients patch-tested 2001-2018, with: 1) medical adhesive (tapes/band aids/adhesive aids/suture glue) source, 2) positive patch test, and 3) final primary diagnosis of allergic contact dermatitis.

RESULTS

313 (0.7%) patients met inclusion criteria. Compared to other patients with final primary diagnosis of allergic contact dermatitis, medical adhesive allergy patients were less likely male (odds ratio 0.58, 95% confidence interval [0.45-0.77]) and/or age >40 (0.76 [0.6-0.96]). The most common NACDG screening series allergens were colophony (80.7%), balsam of Peru (3.9%), 2-hydroxyethyl methacrylate (2.7%) and carba mix (2.7%). One-fourth (79/313, 25.2%) had positive patch test reactions to supplemental allergens/materials, and 17.3% (54/313) 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 suspected medical adhesive contact allergy.

Importance of Supplemental Patch Testing Beyond a Screening Series for Patients With Dermatitis: The North American Contact Dermatitis Group Experience

IMPORTANCE

Patch test screening series for patients with dermatitis are limited and may miss clinically relevant contact allergens.

OBJECTIVE

To characterize individuals with dermatitis who showed clinically relevant patch test findings to supplemental (nonscreening) allergens or substances.

DESIGN, SETTING, AND PARTICIPANTS

A 17-year, retrospective cross-sectional analysis (January 1, 2001, to December 31, 2018) of North American Contact Dermatitis Group (NACDG) data from multiple centers in North America was conducted. A total of 43 417 patients with dermatitis underwent patch testing to the NACDG screening series in a standardized manner with 65 to 70 allergens and supplemental allergens as clinically indicated. Patients with 1 or more clinically relevant reactions to a supplemental (nonscreening) allergen/substance were analyzed between November 18, 2020, and March 12, 2021.

MAIN OUTCOMES AND MEASURES

The main outcomes were to assess the number of patients with clinically relevant reactions to supplemental (nonscreening) allergens and compare characteristics (including demographic characteristics and occupations) between patients with a clinically relevant patch test reaction to 1 or more supplemental allergens or substances (supplement-positive) and those without a reaction (supplement-negative) using odds ratios (ORs) and 95% CIs. Secondary outcomes included sources of allergic contact dermatitis and, for occupationally related cases, specific occupations and industries.

RESULTS

Of 43 417 patients included in the study who underwent patch testing to the NACDG screening series (65-70 allergens), 9507 individuals (21.9%) had currently relevant reactions to 1 or more supplemental allergens or substances. Of these, 6608 were women (69.5%) and the mean (SD) age was 47.2 (0.54) years. Compared with patients who had supplement-negative results, patients with supplement-positive findings were significantly less likely to be male (OR, 0.90; 95% CI, 0.85-0.94; P < .001) and/or have atopic dermatitis (OR, 0.89; 95% CI, 0.84-0.93; P < .001). Common primary sites of dermatitis in 9499 patients with supplement-positive findings included the face (2856 [30.1%]), hands (2029 [21.4%]), and scattered/generalized distribution (1645 [17.3%]). Frequent sources of supplemental allergens in 9235 patients included personal care products (4746 [51.4%]) and clothing/wearing apparel (1674 [18.1%]). Of 9362 patients with available data, supplemental allergens/substances were occupationally related in 1580 (16.9%); of those with identified occupations, 25.1% (384 of 1529) were precision production, craft, or repair workers. Of 9507 patients with supplement-positive findings, 2447 (25.7%) had no currently relevant reactions to NACDG screening allergens.

CONCLUSIONS AND RELEVANCE

This cross-sectional study found that 21.9% of patients who underwent patch testing to an allergen screening series of 65 to 70 allergens had at least 1 relevant reaction to supplemental allergens/substances. Of these, one-quarter reacted only to a supplemental allergen/substance. Screening series include common, important allergens, but these findings suggest that the addition of specialty allergens and personal or work products is critical for the successful diagnosis and management of allergic contact dermatitis.

Occupational photoallergic contact dermatitis to thiourea in a firefighter

Thioureas are a relatively uncommon cause of allergic contact dermatitis and a rare cause of photoallergic contact dermatitis. They are primarily used as vulcanization accelerators in the production of neoprene, and common sources of exposure include gloves, shoe insoles, wet suits, and orthopedic braces. We report a multifactorial case of severe episodic photoallergic contact dermatitis to thiourea in a 29-year-old firefighter. Multiple sources of neoprene exposure were identified, including a firefighting mask, continuous positive airway pressure strap, and hockey helmet.

Patch Testing with Ammonium Persulfate: The North American Contact Dermatitis Group Experience, 2015-2018

BACKGROUND

Ammonium persulfate (APS), an oxidizing agent used in hair products, manufacturing, and pool/spa water, can cause skin reactions including allergic contact dermatitis.

OBJECTIVE

To characterize positive patch test reactions to APS (2.5% pet).

METHODS

Retrospective analysis of patients tested to the North American Contact Dermatitis Group (NACDG) screening series from 2015-2018.

RESULTS

Of 10,526 patients, 193 (1.8%) had positive patch test reactions to APS. Compared to negative patients, APS-positive patients were significantly more likely to be male (43.2% vs. 28.0%, p<0.0001), have primary hand (30.2% vs. 22.0%, p=0.0064), scattered generalized (25.5% vs. 17.9%, p=0.0064), or trunk dermatitis (8.9% vs. 4.9%, p=0.0123), and occupationally-related dermatitis (22.2% vs. 10.9%, p<0.0001). Over half of the APS-positive reactions were currently relevant (57.0%); 19 (9.8%) were related to occupation, especially (68.4%) hairdressers. Swimming pools/spas (23.3%) and hair care products (19.2%) were the most common APS sources.

LIMITATIONS

Immediate reactions and follow-up testing not captured.

CONCLUSIONS

The proportion of patients positive to APS was 1.8%. APS positivity was significantly associated with male sex and hand dermatitis. Swimming pool/spa chemicals are important sources of APS exposure.

Age-related differences in patch testing results among children: Analysis of North American Contact Dermatitis Group Data, 2001-2018

BACKGROUND

An updated understanding of allergic contact dermatitis is needed, particularly in children.

OBJECTIVES

To compare positive and clinically relevant reactions in children versus adults referred for patch testing.

METHODS

Retrospective analysis of 1871 children and 41,699 adults from the North American Contact Dermatitis Group (NACDG) from 2001-2018.

RESULTS

Both final diagnosis of allergic contact dermatitis (55.2% versus 57.3%; chi square, P = .0716) and prevalence of ≥ 1 currently relevant reaction to a NACDG screening allergen (49.2% vs 52.2%; P = .1178) were similar between children and adults. Currently in children, the most common relevant allergens were nickel sulfate (17.3%), hydroperoxides of linalool (7.8%), methylisothiazolinone (7.7%), cobalt chloride (7.0%), and fragrance mix I (4.9%). Approximately a fifth of children had a positive reaction to a non-NACDG allergen.

CONCLUSION

Over half of children referred for patch testing were diagnosed with allergic contact dermatitis. The most common relevant allergens in children were nickel sulfate, cobalt chloride, and hydroperoxides of linalool. Twenty percent of children had at least 1 positive reaction to allergens/substances not on the NACDG screening series, underscoring the need for comprehensive testing.

Prevalence and trend of allergen sensitization in patients referred for patch testing with a final diagnosis of psoriasis: North American Contact Dermatitis Group data, 2001-2016

BACKGROUND

Little is known about the relationship between psoriasis and allergic contact dermatitis (ACD).

OBJECTIVE

To examine the associations with ACD, related clinical characteristics, and common positive and clinically relevant allergens of patients with a final diagnosis of psoriasis who were referred for patch testing.

METHODS

Retrospective analysis of 38 723 patients from the North American Contact Dermatitis Group.

RESULTS

Patients with a final diagnosis of psoriasis had lower proportions of ACD than those without psoriasis (32.7% vs 57.8%). In multivariable logistic regression models, psoriasis was inversely associated with female sex, Black or Asian race, and history of atopic dermatitis and hay fever. Patients with a final diagnosis of psoriasis were less likely to have one or more positive allergic patch-test reactions or to have a current clinically relevant patch-test reaction to the majority of the most commonly positive and/or relevant allergens. The most clinically relevant allergens included nickel sulfate, methylisothiazolinone, and fragrance mix I.

CONCLUSION

Approximately one-third of patients who were referred for patch testing with a final diagnosis of psoriasis were also diagnosed with ACD. In select patients with suspected psoriasis who also have a clinical presentation suggestive of ACD, patch testing may be helpful.

Patch testing with sodium disulfite: North American Contact Dermatitis Group experience, 2017 to 2018

BACKGROUND

Sodium disulfite (SD), also known as sodium metabisulfite, is an increasingly recognized cause of allergic contact dermatitis.

OBJECTIVES

The objective of this work was to characterize individuals with positive patch test reactions to SD as well as analyse reaction strength, clinical relevance, and sources.

METHODS

This is a retrospective analysis of patients patch tested with SD (1% petrolatum) by the North American Contact Dermatitis Group (NACDG), 2017 to 2018.

RESULTS

Of 4885 patients patch tested with SD, 132 (2.7%) had a positive reaction. Common primary anatomic sites of dermatitis were face (28.8%), hands (20.5%), and a scattered/generalized distribution (13.6%). Compared with SD-negative patients, SD-positive patients were more likely male (odds ratio 2.81, 95% confidence interval 1.98-4.00) and/or over 40 years (odds ratio 1.95, 95% confidence interval 1.30-2.94). Reactions were most commonly + (50.4%) or ++ (34.1%); 65.2% were considered currently relevant. About 15.2% were definitively confirmed in sources, commonly personal care products (18.9%, especially hair dye), and drugs/medications/alcoholic beverages (9.1%). Only 2.3% of positive reactions were linked to occupation.

CONCLUSIONS

Positive reactions to SD occurred in 2.7% of tested patients. Reactions were often clinically relevant and linked to personal care products and drugs/medications/alcoholic beverages.

Contact dermatitis associated with preservatives: Retrospective analysis of North American Contact Dermatitis Group data, 1994 through 2016

BACKGROUND

Preservatives are often necessary components of commercial products. Large-scale North American studies on preservative allergy are limited.

OBJECTIVE

To evaluate demographics, positive patch test reactions (PPTRs), clinical relevance, and trends for preservatives tested by the North American Contact Dermatitis Group.

METHODS

We conducted a retrospective cross-sectional analysis of North American Contact Dermatitis Group patch testing results of preservatives from 1994 through 2016.

RESULTS

A total of 50,799 patients were tested; 11,338 (22.3%) had a PPTR to at least 1 preservative. The most frequent reactions were to methylisothiazolinone 0.2% aqueous (aq) (12.2%), formaldehyde 2% aq (7.8%), formaldehyde 1% aq (7.8%), quaternium-15 2% petrolatum (pet) (7.7%), and methyldibromo glutaronitrile/phenoxyethanol 2% pet (5.1%). Paraben mix 12% pet (1%), iodopropynyl butylcarbamate 0.1% pet (0.4%), benzyl alcohol 1% pet (0.3%), and phenoxyethanol 1% pet (0.2%) had the lowest PPTRs. Linear regression analysis of preservatives tested showed that only methylchloroisothiazolinone/methylisothiazolinone 0.01% aq (parameter estimate, 0.42; 95% CI, 0.17-0.66; P < .005) had a significant increase in PPTRs over time.

LIMITATIONS

Collected variables are dependent on clinical judgment. Results may be prone to referral selection bias.

CONCLUSIONS

This large North American study provides insight on preservative PPTRs and trends from 1994 through 2016.

Prevalence and Trend of Allergen Sensitization in Adults and Children with Atopic Dermatitis Referred for Patch Testing, North American Contact Dermatitis Group Data, 2001-2016

BACKGROUND

The association between atopic dermatitis (AD) and allergic contact dermatitis (ACD) is controversial.

OBJECTIVE

To analyze the prevalence, reaction strength, and trends of the most commonly positive and relevant allergens in patients with AD referred for patch testing.

METHODS

This was a retrospective analysis of 38,482 patients from the North American Contact Dermatitis Group, 2001 to 2016.

RESULTS

Most adults (56.0%) and children (52.8%) with a history of AD had a final diagnosis of ACD. Adults (66.5% vs 65.6%; χ², P = .1459) and children (61.4% vs 62.3%, P = .7074) with or without a history of AD had similar proportions of one or more allergic patch test reactions. Adults with a history of AD had a greater number of allergic patch test positive reactions than those without it (2.0 ± 2.4 vs 1.9 ± 2.3; t test, P < .0001), whereas children did not (1.5 ± 1.8 vs 1.4 ± 1.6; P = .3839). Nickel sulfate, methylisothiazolinone, formaldehyde, fragrance mix I, sodium gold thiosulfate, and thimerosal were the most common allergens in adults and children with a history of AD. In multivariable logistic regression models, adults with versus without a history of AD had increased odds of reacting to 10 of the top 25 North American Contact Dermatitis Group screening allergens. Most allergens had similar strengths of reaction in adults or children with and without a history of AD or a current AD diagnosis; cobalt, fragrance mix I, and propylene glycol had weaker reactions. In multivariable logistic regression, adults with versus without an AD history had increased odds of relevance for 10 of the 25 most currently relevant allergens, whereas children with an AD history did not have increased relevance for any specific allergens.

CONCLUSIONS

Most patients referred for patch testing with AD history had a final diagnosis of ACD. Patients with AD history had a similar likelihood of having a positive patch test reaction as those without an AD history. Adults with an AD history had a higher number of positive patch test reactions.

Occupational contact dermatitis: Retrospective analysis of North American Contact Dermatitis Group Data, 2001 to 2016

BACKGROUND

Patch testing is an important diagnostic tool for suspected allergic contact dermatitis (ACD) in occupational settings.

OBJECTIVE

Provide an overview of occupational skin disease (OSD) and an analysis of occupational ACD in North American patients undergoing patch testing between 2001and 2016.

METHODS

Patients with OSD were analyzed for frequency of allergic reactions to a screening series of allergens, occupational relevance, location of skin disease, and exposure sources. Demographic, occupation, and industry information were recorded.

RESULTS

Of 38,614 patients evaluated, 4471 (11.6%) had OSD, of whom 3150 (70.5%) had ACD. The most common occupationally related allergens included rubber accelerators, preservatives, and bisphenol A epoxy resin. Hands (75.8%), arms (30.0%), and face (15.9%) were common sites of dermatitis. The occupations most affected were service workers and machine operators.

LIMITATIONS

Our cohort may not reflect the general working population.

CONCLUSION

This study identified common occupational allergens, exposure sources, and occupations/industries at risk. This information may help the clinician evaluate and manage patients with occupational contact dermatitis.

Prevalence and trend of allergen sensitization in patients with nummular (discoid) eczema referred for patch testing: North American Contact Dermatitis Group data, 2001-2016

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.

Hand eczema in children referred for patch testing: North American Contact Dermatitis Group Data, 2000-2016

BACKGROUND

Little is known about the aetiologies and relevant allergens in paediatric patients with hand eczema (HE).

OBJECTIVES

To characterize the aetiologies and determine the proportion of positive and currently relevant allergens in children/adolescents (age < 18 years) with HE referred for patch testing.

METHODS

A retrospective analysis (2000-2016) of North American Contact Dermatitis Group data was performed.

RESULTS

Of 1634 paediatric patients, 237 (14·5%) had involvement of the hands. Final physician diagnoses included allergic contact dermatitis (49·4%), atopic dermatitis (37·1%) and irritant contact dermatitis (16·9%). In multivariable logistic regression models, employment was the only association with increased odds of any HE or primary HE. Children with HE vs. those without HE had similar proportions of positive patch tests (56·1% vs. 61·7%; χ² -test, P = 0·11). The five most common currently relevant allergens were nickel, methylisothiazolinone, propylene glycol, decyl glucoside and lanolin. In multivariable logistic regression models of the top 20 relevant allergens, HE was associated with significantly higher odds of currently relevant reactions to lanolin, quaternium-15, Compositae mix, thiuram mix, 2-mercaptobenzathiazole and colophony. The allergens with the highest mean significance-prevalence index number were methylisothiazolinone, carba mix, thiuram mix, nickel and methylchloroisothiazolinone/methylisothiazolinone.

CONCLUSIONS

Children with HE who were referred for patch testing had a high proportion of positive patch tests, which was similar to the proportion found in children without HE. Children with HE had a distinct and fairly narrow profile of currently relevant allergens.

Facial Dermatitis in Male Patients Referred for Patch Testing: Retrospective Analysis of North American Contact Dermatitis Group Data, 1994 to 2016

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.

Evaluation of Patch Test Findings in Patients With Anogenital Dermatitis

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.

Scalp involvement in patients referred for patch testing: Retrospective cross-sectional analysis of North American Contact Dermatitis Group data, 1996 to 2016

BACKGROUND

Scalp conditions are often multifactorial.

OBJECTIVE

To characterize patients with scalp involvement and patch-testing outcomes.

METHODS

Retrospective cross-sectional analysis of North American Contact Dermatitis Group data (1996-2016). Study groups included patients with scalp involvement (≤3 anatomic sites coded) with or without additional sites.

RESULTS

A total of 4.8% of patients (2331/48,753) had scalp identified as 1 of up to 3 affected anatomic sites. Approximately one-third of "scalp-only" individuals had a specific primary diagnosis of allergic contact dermatitis (38.6%), followed by seborrheic dermatitis (17.2%) and irritant contact dermatitis (9.3%). When adjacent anatomic sites were affected, allergic contact dermatitis was more frequently identified as the primary diagnosis (>50%). The top 5 currently clinically relevant allergens in scalp-only patients were p-phenylenediamine, fragrance mix I, nickel sulfate, balsam of Peru, and cinnamic aldehyde. Methylisothiazolinone sensitivity was notable when adjacent anatomic sites were involved. The top 3 specifically identified sources for scalp-only allergens were hair dyes, shampoo/conditioners, and consumer items (eg, hair appliances, glasses).

LIMITATIONS

Tertiary referral population.

CONCLUSION

Isolated scalp involvement was less likely to be associated with allergic contact dermatitis than when adjacent anatomic sites were involved. Overlap with multiple diagnoses was frequent, including seborrheic dermatitis, irritant dermatitis, other dermatoses, or all 3. p-Phenylenediamine was the most common allergen.

Eyelid dermatitis in patients referred for patch testing: Retrospective analysis of North American Contact Dermatitis Group data, 1994-2016

BACKGROUND

Eyelid dermatitis is a common dermatologic complaint.

OBJECTIVE

To characterize patients with eyelid dermatitis.

METHODS

Retrospective analysis (1994-2016) of North American Contact Dermatitis Group data.

RESULTS

Of 50,795 patients, 2332 (4.6%) had eyelid dermatitis only, whereas 1623 (3.2%) also had dermatitis of the eyelids and head or neck. Compared with patients without eyelid involvement (n = 26,130), groups with eyelid dermatitis only and dermatitis of the eyelid and head or neck were significantly more likely to be female, white, and older than 40 years, and to have a history of hay fever, atopic dermatitis, or both (P < .01). Final primary diagnoses included allergic contact dermatitis (eyelid dermatitis only: 43.4%; dermatitis of the eyelid and head or neck: 53.5%), irritant contact dermatitis (eyelid dermatitis only: 17.0%; dermatitis of the eyelid and head or neck: 9.8%), and atopic dermatitis (eyelid dermatitis only: 13.1%; dermatitis of the eyelid and head or neck: 13.8%). Top 5 currently relevant allergens included nickel sulfate (eyelid dermatitis only: 18.6%; dermatitis of the eyelid and head or neck: 22.5%), fragrance mix I (eyelid dermatitis only: 16.5%; dermatitis of the eyelid and head or neck: 18.3%), methylisothiazolinone (eyelid dermatitis only: 16.5%; dermatitis of the eyelid and head or neck: 17.7%), gold sodium thiosulfate (eyelid dermatitis only: 14.7%; dermatitis of the eyelid and head or neck: 11.4%), and balsam of Peru (eyelid dermatitis only: 11.9%; dermatitis of the eyelid and head or neck: 12.6%). Both eyelid-involvement groups were significantly more likely to react to gold sodium thiosulfate, carmine, shellac, dimethylaminopropylamine, oleamidopropyl dimethylamine, and thimerosal (P < .05) compared with the no eyelid involvement group.

LIMITATIONS

Lack of specific distribution patterns of eyelid dermatitis and no long-term follow-up data.

CONCLUSION

Patch testing remains a critical tool in evaluating patients with eyelid dermatitis.

Allergic Contact Dermatitis and Autoeczematization to Proctosedyl® Cream and Proctomyxin® Cream

Proctosedyl® and Proctomyxin® are two commonly prescribed hemorrhoid therapies. Their topical application to the perianal region may be complicated by a local allergic contact dermatitis and subsequent autoeczematization reaction. We present three cases of an autoeczematization (ID) reaction to varying topical allergens found in Proctosedyl®/Proctomyxin®. It is our recommendation that physician and patient education, avoidance of allergens (or cross-reactants), and appropriate choice of topical corticosteroid is important in preventing and avoiding flares.

Photo Developer Allergic Contact Dermatitis in a Photographer Following Paraphenylenediamine Sensitization from a Temporary Henna Tattoo

Background:

Paraphenylenediamine (PPD) is a coloring agent and potent sensitizer commonly added to henna tattoos to darken tattoo color. Photographic developers contain compounds that cross-react with PPD. Allergic contact dermatitis (ACD) from photo developers has been documented in the literature.

Objective:

We describe the rare case of a photographer who presented with a 4-year history of recurrent ACD following exposure to photochemicals. History taking revealed that 10 years before presentation, he had received a temporary henna tattoo.

Methods:

The patient was patch-tested with 4-methylaminophenol sulfate (Metol), the North American Contact Dermatitis Group (NACDG) series, and select other allergens.

Results:

Patch testing results revealed strong positive reactions to 4-methylaminophenol sulfate and PPD.

Conclusion:

This is the first report to our knowledge of ACD from a photo developer occurring as a consequence of previous sensitization to PPD from a temporary henna tattoo. Due to the potential for long-term sequelae, an awareness of the risks associated with henna tattoos is warranted.

Occupational contact allergens: are they also associated with occupational asthma?

BACKGROUND

Workplace exposures that can potentially cause both allergic occupational contact dermatitis (AOCD) and occupational asthma (OA) are not clearly identified.

METHODS

Occupational contact allergens (OCAs) were identified using North American Contact Dermatitis Group (NACDG) data. Reference documents and systematic reviews were used to determine whether each OCA had been reported to potentially cause OA. The presence or absence of a sensitizer notation in occupational hygiene reference documents was also examined.

RESULTS

The 10 most common OCAs were: epoxy resin*, thiuram, carba mix, nickel sulfate*, cobalt chloride*, potassium dichromate*, glyceryl thioglycolate, p-phenylenediamine*, formaldehyde* and glutaraldehyde*. Seven (indicated by *) were determined to be possible causes of OA. Information on sensitizing potential from OH reference materials contained conflicting information.

CONCLUSIONS

Several common OCAs can also potentially cause OA. Inhalation and dermal exposures to these agents should be controlled and both OA and AOCD should be considered as possible health outcomes. Increased consistency in sensitizer notations is needed.

Positive patch-test reactions to iodopropynyl butylcarbamate: retrospective analysis of North American contact dermatitis group data, from 1998 to 2008

BACKGROUND

iodopropynyl butylcarbamate (IPBC), a commonly used preservative, is found in industrial and personal care products.

OBJECTIVE

to evaluate prevalence, clinical relevance, occupational relationship, and sources of positive reactions to IPBC in patients in North America.

METHODS

the North American Contact Dermatitis Group (NACDG) tested IPBC 0.1% and/or 0.5% in petrolatum (pet) between 1998 and 2008. Two patient groups of interest were defined, based on patch-test reactions to IPBC: weak (+) reactors and strong (++ or +++) reactors. Patient characteristics, site(s) of dermatitis, sources of positive reactions, clinical relevance, and occupational relevance to IPBC were tabulated.

RESULTS

of the 25,321 patients tested, there were 226 (0.9%) weak reactors and 67 (0.3%) strong reactors. For IPBC-positive patients, the most frequent sites of dermatitis were scattered generalized distribution, hands, and arms. The majority (> 50%) of currently relevant reactions were to personal care products, and most reactions (> 90%) were not related to occupation. Only four of the strong reactors had definite clinical relevance (positive use-test reaction or positive patch-test reaction to a product containing IPBC). The frequency of positive reactions increased (0.2% vs 1.5%) when the higher concentration of IPBC was utilized, but most (> 64%) were weak reactions, of which some were likely irritant.

CONCLUSIONS

allergy to IPBC is relatively uncommon. When clinically relevant, personal care products were the most likely allergen source. Because IPBC is a marginal irritant, caution should be utilized when testing with higher concentrations of IPBC (≥ 0.5% pet) and when interpreting weak (+) reactions. Verification of clinical relevance by use test or repeat patch testing or both is also important.