Frances J. Storrs

North American Contact Dermatitis Group patch test results for the detection of delayed-type hypersensitivity to topical allergens

BACKGROUND Allergic contact dermatitis is a significant cause of cutaneous disease affecting many individuals. Patch testing, when used properly, often provides support for the diagnosis of allergic contact dermatitis. OBJECTIVE This article reports patch testing results from July 1, 1994, to June 30, 1996, by the North American Contact Dermatitis Group (NACDG). METHODS Patients evaluated in our patch test clinics were tested with the same screening series of allergens by the use of a standardized patch testing technique. The data from these patients were recorded on a standard computer entry form and analyzed. RESULTS Forty-nine allergens were tested on 3120 patients. Budesonide was added to the series in July 1995 and tested on 1678 patients. Of these patients, 66.5% had positive allergic patch test reactions, and 57% had at least one allergic reaction that was felt to be clinically relevant to the present or past dermatitis. The 20 screening allergens commercially available to United States dermatologists in the Allergen Patch Test Kit, accounted for only 54.1% of the patients with positive allergic reactions. The additional 30 allergens on the NACDG screening series accounted for 47% of patients with positive allergic reactions. Had the Allergen Patch Test Kit alone been used, 12.4% of all patients tested may have had their disease misclassified as a nonallergic disorder, and an additional 34.4% of all tested patients would not have had their allergies fully defined. Among those patients with positive responses to the supplemental allergens, 81% of the responses were of present or past relevance. The 12 most frequent contact allergens were nickel sulfate, fragrance mix, thimerosal, quaternium-15, neomycin sulfate, formaldehyde, bacitracin, thiuram mix, balsam of Peru, cobalt chloride, para-phenylenediamine, and carba mix. The present relevance varied with the specific allergen from 10.7% (thimerosal) to 85.7% (quaternium-15). Among newer allergens, methyldibromoglutaronitrile/phenoxyethanol (cosmetic preservative) caused positive allergic reactions in 2% of the patients; tixocortol-21-pivalate and budesonide (corticosteroids), in 2.0% and 1.1% of the patients, respectively; and ethylene urea/melamine formaldehyde mix (textile resin), in 5% of the patients. CONCLUSION The usefulness of patch testing is enhanced with the number of allergens tested, because allergens not found on the commercially available screening series in the United States frequently give relevant allergic reactions.

North American Contact Dermatitis Group patch-test results, 2001-2002 study period.

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.

North American Contact Dermatitis Group Patch-test Results, 1998 to 2000

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.

North American Contact Dermatitis Group patch test results: 2009 to 2010.

Background Patch testing is an important diagnostic tool for determination of substances responsible for allergic contact dermatitis. Objective This study reports the North American Contact Dermatitis Group (NACDG) patch testing results from January 1, 2009, to December 31, 2010. Methods At 12 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 &khgr;2 statistics. Results A total of 4308 patients were tested. Of these, 2614 (60.7%) had at least 1 positive reaction, and 2284 (46.3%) were ultimately determined to have a primary diagnosis of allergic contact dermatitis. Four hundred twenty-seven (9.9%) patients had occupationally related skin disease. There were 6855 positive allergic reactions. As compared with the previous reporting period (2007–2008), the positive reaction rates statistically decreased for 20 allergens (nickel, neomycin, Myroxylon pereirae, cobalt, formaldehyde, quaternium 15, methydibromoglutaronitrile/phenoxyethanol, methylchlorisothiazolinone/methylisothiazolinone, potassium dichromate, diazolidinyl urea, propolis, dimethylol dimethylhydantoin, 2-bromo-2-nitro-1,3-propanediol, methyl methacrylate, ethyl acrylate, glyceryl thioglycolate, dibucaine, amidoamine, clobetasol, and dimethyloldihydroxyethyleneurea; P < 0.05) and statistically increased for 4 allergens (fragrance mix II, iodopropynyl butylcarbamate, propylene glycol, and benzocaine; P < 0.05). Approximately one quarter of tested patients had at least 1 relevant allergic reaction to a non-NACDG allergen. Hypothetically, approximately one quarter of reactions detected by NACDG allergens would have been missed by TRUE TEST (SmartPractice Denmark, Hillerød, Denmark). Conclusions These results affirm the value of patch testing with many allergens.

North American contact dermatitis group patch test results: 2011-2012.

BackgroundPatch testing is an important diagnostic tool for assessment of allergic contact dermatitis (ACD). ObjectiveThis study documents the North American Contact Dermatitis Group (NACDG) patch-testing results from January 1, 2011, to December 31, 2012. MethodsAt 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 &khgr;2 statistics. ResultsFour 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). ConclusionsThese 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.

North American Contact Dermatitis Group patch test results for 2007-2008.

BackgroundThe North American Contact Dermatitis Group (NACDG) tests patients with suspected allergic contact dermatitis to a broad series of screening allergens and publishes periodic reports. ObjectiveThe 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 MaterialsStandardized patch testing with 65 allergens was used at 13 centers in North America. &khgr;2 analysis was used for comparisons. ResultsA 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. ConclusionsPeriodic 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.

North American Contact Dermatitis Group patch-test results, 2003-2004 study period

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.

The case for patch test readings beyond day 2: Notes from the lost and found department

Additional patch test readings taken after 2 days (48 hours) are valuable in distinguishing false-positive reactions, which may occur up to 22% of the time. Second readings taken on days 3 through 7 may detect an additional 34% positive reactivity. Those reactions, both lost (initially positive, later negative) and found (initially negative, later positive) by delayed readings, require clinical correlation for relevance as do the readings that persist at and beyond day 2 (positive at both readings).

Screening allergens for acrylate dermatitis associated with artificial nails

Background: Acrylates are increasingly observed to be a cause of allergic contact dermatitis (ACD), especially in the cosmetic industry. Patients suspected of acrylate allergy are generally tested to 33 acrylates, and acrylate-allergic patients commonly react positively to many of these allergens. Objective: The objective of the study was to develop a short list of screening acrylates to diagnose acrylate allergy in patients wearing artificial nails. Methods: Twenty-three patients with ACD to acrylates were studied and their patch test reaction rates to 33 acrylates analyzed to identify the acrylates that were most frequently positive. Results: Based on the frequency with which each acrylate was positive in a group of 11 patients wearing artificial nails and the known use of specific acrylates in the nail industry, ethyl acrylate, 2-hydroxy ethyl acrylate, etylene glycol dimethacrylate, ethyl α cyanoacrylate, and triethylene glycol diacrylate were identified as screening acrylates. Conclusion: The pattern of acrylate cross-reactivity among the most frequently positive acrylates suggests that a functional group that is a “carboxy ethyl side group” may be requisite for ACD to acrylates.

Patch testing in children from 2005 to 2012: Results from the North American contact dermatitis group

BackgroundAllergic contact dermatitis is common in children. Epicutaneous patch testing is an important tool for identifying responsible allergens. ObjectiveThe objective of this study was to provide the patch test results from children (aged ⩽18 years) examined by the North American Contact Dermatitis Group from 2005 to 2012. MethodsThis is a retrospective analysis of children patch-tested with the North American Contact Dermatitis Group 65- or 70-allergen series. Frequencies and counts were compared with previously published data (2001–2004) using &khgr;2 statistics. ConclusionsA total of 883 children were tested during the study period. A percentage of 62.3% had ≥1 positive patch test and 56.7% had ≥1 relevant positive patch test. Frequencies of positive patch test and relevant positive patch test reaction were highest with nickel sulfate (28.1/25.6), cobalt chloride (12.3/9.1), neomycin sulfate (7.1/6.6), balsam of Peru (5.7/5.5), and lanolin alcohol 50% petrolatum vehicle (5.5/5.1). The ≥1 positive patch test and ≥1 relevant positive patch test in the children did not differ significantly from adults (≥19 years) or from previously tested children (2001–2004). The percentage of clinically relevant positive patch tests for 27 allergens differed significantly between the children and adults. A total of 23.6% of children had a relevant positive reaction to at least 1 supplemental allergen. Differences in positive patch test and relevant positive patch test frequencies between children and adults as well as test periods confirm the importance of reporting periodic updates of patch testing in children to enhance clinicians’ vigilance to clinically important allergens.