The Association of Race/Ethnicity and Patch Test Results: North American Contact Dermatitis Group, 1998-2006.

BACKGROUND: The North American Contact Dermatitis Group patch tests patients with suspected allergic contact dermatitis (ACD) to a broad series of screening allergens and publishes periodic reports. We have previously reported on the association of race and ethnicity with the rates of positive responses to standard patch test allergens. This report extends those observations. OBJECTIVE: The aim of the study was to report the North American Contact Dermatitis Group patch testing results from January 1, 1998, to December 31, 2006, comparing the frequency of positive reactions between white and black subjects. METHODS AND MATERIALS: Standardized patch testing with 45 allergens was used at 13 centers in North America. χ analysis of results in black subjects as compared with whites was examined. RESULTS: A total of 19,457 patients were tested; 92.9% (17,803) were white and 7.1% (1,360) were black. The final diagnoses of ACD (whites, 45.9%; blacks, 43.6%) and irritant contact dermatitis (13.0%/13.3%) were similar in the 2 groups. The diagnosis of atopic dermatitis was less common in the white patients (8.9%) as compared with the black patients (13.3%). Positive patch test reactions rates were similar for most allergens. However, statistically, blacks reacted more frequently to p-phenylenediamine (7.0% vs 4.4%, P < 0.001), bacitracin (11.6% vs 8.3%, P = 0.0004), as well as specific rubber accelerators mercaptobenzothiazole (2.7% vs 1.8%), thiuram (6.2% vs 4.3%), and mercapto mix (1.9% vs 0.8%, P < 0.001). Whites had an increase in positive reactions to fragrances (12.12% vs 6.77%, P < 0.0001), formaldehyde (9.25% vs 5.45%, P < 0.0001), and some formaldehyde releaser preservatives used in personal care products and textile resins (9.80% vs 6.18%, P < 0.0001). CONCLUSIONS: There were statistically different rates of positive patch test reactions to specific allergens between black and white patients suspected of having ACD. The etiology of these differences is unclear but probably relates to culturally determined exposure patterns rather than genetic differences.

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

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.

Occupational contact dermatitis in hairdressers/cosmetologists: retrospective analysis of north american contact dermatitis group data, 1994 to 2010.

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.

Positive patch test reactions in older individuals: retrospective analysis from the North American Contact Dermatitis Group, 1994-2008.

BACKGROUND: Relatively little is known about the epidemiology of allergic contact dermatitis in older individuals. OBJECTIVES: We sought to determine the frequency of positive and clinically relevant patch test reactions in older individuals (≥ 65 years old) referred for patch testing, and to compare these results with those of adults (≤ 64-19 years) and children (<18 years). DESIGN: This was a retrospective cross-sectional analysis of North American Contact Dermatitis Group data from 1994 to 2008. RESULTS: A total of 31,942 patients (older n = 5306; adults n = 25,028; children n = 1608) were patch tested. The overall frequency of at least one allergic reaction in older individuals was 67.3% as compared with 66.9% for adults (P = .5938) and 47% for children (P = .0011). Reaction rates that were statistically higher in older individuals as compared with both adults and children included: Myroxylon pereirae, fragrance mix I, quaternium-15, formaldehyde, imidazolidinyl urea, diazolidinyl urea, neomycin, bacitracin, methyldibromo glutaronitrile, methyldibromo glutaronitrile/phenoxyethanol, ethyleneurea melamine formaldehyde mix, and carba mix (P values < .0004). Patch test reaction rates that were significantly lower in older individuals than both comparison groups included: nickel, thimerosal, and cobalt (P values < .0001). LIMITATIONS: Referral population was a limitation. CONCLUSIONS: Older individuals were more likely to have at least one positive patch test reaction as compared with children, but had similar rates to adults. The frequency of positive reactions to specific allergens differed by age group, most likely as a result of exposures.

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.

Positivity ratio and reaction index: patch-test quality-control metrics applied to the north american contact dermatitis group database.

BACKGROUND: The positivity ratio (PR) and reaction index (RI) characterize the ability of patch-test preparations to produce strong (++ or +++) reactions as opposed to weak (+), questionable, or irritant reactions. OBJECTIVE: This study evaluates these measures for North American Contact Dermatitis Group (NACDG) patch-test preparations. METHODS: The PR and RI were calculated for 79 NACDG standard allergens tested from 1994 to 2006 (n = 26,479 patients). The median values were used as cutoff values for "acceptable" versus "problematic" preparations. RESULTS: The top 10 "acceptable" patch-test preparations (PR < or = 55 and RI > 0.46) were mixed dialkyl thioureas 1% in petrolatum (pet), tixocortol-21-pivalate 1% pet, ethylenediamine dihydrochloride 1% pet, sesquiterpene lactone mix 0.1% pet, nickel sulfate 2.5% pet, bacitracin 20% pet, thimerosal 0.1% pet, epoxy resin 1% pet, colophony 20% pet, and mercaptobenzothiazole 1% pet. The most "problematic" patch-test preparations (PR > 55 and RI < or = 0.46) were cocamidopropyl betaine 1% aqueous (aq), benzalkonium chloride 0.1% aq, jasmine absolute 2% pet, iodopropynyl butyl carbamate 0.1% pet, 2-bromo-2-nitropropane-1,3-diol 0.5% pet, methyldibromoglutaronitrile 0.4% pet, methyldibromoglutaronitrile/phenoxyethanol 2% pet and 2.5% pet, dimethylol dihydroxyethyleneurea 4.5% aq, and clobetasol-17-propionate 1% pet. CONCLUSION: Caution should be used when interpreting reactions to "problematic" patch-test preparations with a high proportion of weak, irritant, and questionable reactions.

Positive patch test reactions to lanolin: cross-sectional data from the north american contact dermatitis group, 1994 to 2006.

BACKGROUND: The prevalence of lanolin sensitivity in referred patients is less than 4%. OBJECTIVES: To (1) describe patients with positive patch-test reactions to lanolin, (2) determine clinical and occupational relevance associated with reactions to lanolin and common sources, and (3) examine the frequency of co-reacting allergens. METHODS: A retrospective analysis of 26,479 patients patch-tested by the North American Contact Dermatitis Group (NACDG), 1994 to 2006. RESULTS: Overall, 2.5% of patients (643 of 25,811) tested to lanolin alcohol 30% in petrolatum had positive reactions. Prevalence decreased from 3.7% in 1996 to 1998 to 1.8% in 2005 to 2006 (p <.0001); 83.4% of all positive reactions were currently relevant, but only 2.5% were occupationally relevant. Lanolin-positive patients were 1.2 times more likely to be male and 1.4 times more likely to have a history of atopic dermatitis when compared to allergic, but lanolin-negative, patients (p < .0002 and p < .0001, respectively). Cosmetics were the most common source. Lanolin-positive patients were significantly more likely to be co-sensitized to another NACDG standard screening allergen (p <.0001). CONCLUSIONS: The prevalence of allergic patch-test reactions to lanolin in North America patch-test populations is decreasing. Current relevance of reactions was high, but occupational relevance was low. Concomitant reactions were more common in lanolin-positive patients.

Patch-test results of the North American Contact Dermatitis Group 2005-2006.

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.

Positive patch-test reactions to propylene glycol: a retrospective cross-sectional analysis from the North American Contact Dermatitis Group, 1996 to 2006.

BACKGROUND: Propylene glycol (PG) may cause allergic or irritant contact dermatitis. It primarily functions as a vehicle, solvent, or emulsifier in cosmetics and topical medications. OBJECTIVES: To characterize the prevalence of positive patch-test reactions to PG and the epidemiology of affected patients. METHODS: Retrospective analysis of cross-sectional data compiled by the North American Contact Dermatitis Group (NACDG) from 1996 to 2006. RESULTS: Of 23,359 patients, 810 (3.5%) had allergic patch-test reactions to 30% PG; 12.8% of the reactions were of definite clinical relevance (positive reaction to a personal product containing PG), 88.3% were considered to be currently relevant (definite, probable, or possible relevance), and 4.2% of reactions were occupation related, most commonly to mechanical and motor vehicle occupations. Common sources of PG were personal care products (creams, lotions, and cosmetics, 53.8%), topical corticosteroids (18.3%), and other topical medicaments (10.1%). In patients positive only to PG (n = 135), the face was most commonly affected (25.9%), followed by a scattered or generalized pattern (23.7%). The most common concomitant reactions included reactions to Myroxilon pereirae, fragrance mix, formaldehyde, bacitracin, methyldibromoglutaronitrile/phenoxyethanol, carba mix, and tixocortol pivalate. CONCLUSIONS: In this select population of patients referred for patch testing, allergic reactions to PG were often currently clinically relevant but were rarely related to occupation. The most common sources were personal care products and topical corticosteroids.

Allergic patch test reactions associated with cosmetics: retrospective analysis of cross-sectional data from the North American Contact Dermatitis Group, 2001-2004.

BACKGROUND: Allergy to cosmetics is common. OBJECTIVES: We sought to characterize patients with positive patch test reactions associated with a cosmetic source, to identify common allergens; and to explore gender and occupational associations. METHODS: We performed a retrospective, cross-sectional analysis. RESULTS: Of 6621 female and 3440 male patients, 1582 female (23.8%) and 611 of male (17.8%) patients had at least one allergic patch test reaction associated with a cosmetic source. Of "allergic" patients (>1 allergic reaction, n = 6815), females were 1.21 times more likely to have an allergic reaction associated with a cosmetic source than were male patients (p < .0001, 95% confidence interval [CI] 1.12-1.31). Within the "cosmetic allergic" group (n = 2243), head and neck involvement was significantly higher in female than in male patients (49.3% vs 23.7%, p < .0001). One hundred twenty-five patients had occupationally related allergic reactions associated with a cosmetic. LIMITATIONS: This study is limited by its cross-sectional, retrospective design. CONCLUSION: Of all patients studied, 21.8% had an allergic reaction associated with a cosmetic. Site of dermatitis, cosmetic categories, and specific allergens differed somewhat by gender.

Contact dermatitis associated with food: retrospective cross-sectional analysis of North American Contact Dermatitis Group data, 2001-2004.

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.

Occupation-related contact dermatitis in North American health care workers referred for patch testing: cross-sectional data, 1998 to 2004.

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.

Contact allergy in children referred for patch testing: North American Contact Dermatitis Group data, 2001-2004.

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.

Positive patch-test reactions to mixed dialkyl thioureas: cross-sectional data from the North American Contact Dermatitis Group, 1994 to 2004.

BACKGROUND: Allergic contact dermatitis from thioureas is uncommon but may result from exposure to rubber, especially neoprene. OBJECTIVES: To (1) describe the population with positive patch-test reactions to mixed dialkyl thioureas (MDTU) (ie, diethylthiourea and dibutylthiourea); (2) determine clinical and occupational relevance associated with reactions to MDTU and identify the most commonly related sources and occupations; and (3) examine the frequency of co-reacting allergens in MDTU-positive patients. METHODS: A retrospective analysis of cross-sectional data of 22,025 patients patch-tested by the North American Contact Dermatitis Group between 1994 and 2004. RESULTS: Of 21,898 patients tested with MDTU, 225 (1.0%) had positive reactions; of these, 173 (76.9%) were currently relevant and 29 (17.1%) were occupationally relevant. Patients positive to MDTU were 2.6 times more likely to have foot involvement than patients with positive reactions to other allergens (p < .0001). Footwear was the most commonly identified source overall (20.0%) whereas gloves were the most common occupational source. Of the 173 patients with currently relevant MDTU reactions, 24.9% also reacted to another rubber allergen. CONCLUSIONS: Current clinical relevance of reactions to MDTU was high; occupational relevance was less frequent. Patch tests with common rubber allergens (carbamates, thiurams, and mercaptobenzothiazole) may fail to detect many cases of thiourea-induced rubber allergic contact dermatitis.

Patch-testing North American lip dermatitis patients: data from the North American Contact Dermatitis Group, 2001 to 2004.

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.

The value of patch testing patients with a scattered generalized distribution of dermatitis: retrospective cross-sectional analyses of North American Contact Dermatitis Group data, 2001 to 2004.

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.

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.

Anogenital dermatitis in patients referred for patch testing: retrospective analysis of cross-sectional data from the North American Contact Dermatitis Group, 1994-2004.

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 associations. DESIGN: Retrospective, cross-sectional analysis of the North American Contact Dermatitis Group database, 1994-2004. PATIENTS: Five hundred seventy-five patients with anogenital signs or symptoms were referred for patch testing; 347 had anogenital disease only. MAIN OUTCOME MEASURE: Currently relevant allergic patch test reaction in patients with anogenital signs or symptoms. RESULTS: Sex percentages and mean age were not significantly different in patients with anogenital involvement only compared with those without anogenital involvement. In patients with anogenital involvement only, a final diagnosis of "other dermatoses" was statistically significantly more common in female patients compared with male patients (n = 347; relative risk, 1.99; 95% confidence interval, 1.37-2.91), but the diagnosis of allergic contact dermatitis was not associated with sex. Specific allergens that were statistically significantly more common in patients with anogenital involvement included cinnamal (or cinnamic aldehyde), dibucaine, benzocaine, hydrocortisone-17-butyrate, and budesonide (all P < .005). Those that were statistically significantly less frequent included quaternium-15, cobalt chloride, formaldehyde, p-phenylenediamine, and thiuram mix (all P < .04). Seventy-three patients had anogenital allergic contact dermatitis, defined as anogenital involvement only, allergic contact dermatitis as the only diagnosis, and at least 1 positive reaction of current clinical relevance. In that subgroup, the most common allergen sources were cosmetics, medications, and corticosteroids. CONCLUSION: In patients in the North American Contact Dermatitis Group with anogenital involvement only, male and female patients were equally likely to have allergic contact dermatitis but female patients were more likely to have other dermatoses. Common allergens and sources consisted of those likely to have contact with the anogenital area.

Patch-test reactions to topical anesthetics: retrospective analysis of cross-sectional data, 2001 to 2004.

BACKGROUND: Allergy to topical anesthetics is not uncommon. The cross-reactivity among topical anesthetics and the screening value of benzocaine alone are not well understood. OBJECTIVES: The goals for this study were: (1) to evaluate the frequency and pattern of allergic patch-test reactions to topical anesthetics, using North American Contact Dermatitis Group (NACDG) data, and (2) to compare these results to allergen frequencies from other published studies. METHODS: The NACDG patch-tested 10,061 patients between 2001 and 2004. In this analysis patients were included who had positive patch-test reactions to one or more of the following: benzocaine, lidocaine, dibucaine, tetracaine, and prilocaine. RESULTS: Of patch-tested patients, 344 (3.4%) had an allergic reaction to at least one anesthetic. Of those, 320 (93.0%) had an allergic reaction to only one topical anesthetic. Overall, reactions to benzocaine (50.0%, 172 of 344) were most prevalent, followed by reactions to dibucaine (27.9%, 96 of 344); however, reactions to dibucaine were significantly more frequent in Canada than in the United States (relative risk [RR], 2.31; 95% confidence interval [CI], 1.67-3.20; p < .0001). Of patients reacting to more than one anesthetic, most (79%, 19 of 24) reacted to both an amide and an ester. CONCLUSIONS: Of the topical anesthetics tested, benzocaine was the most frequent allergen overall. Over 50% of allergic reactions to topical anesthetics in this study would have been missed had benzocaine been used as a single screening agent. Cross-reactivity patterns were not consistent with structural groups.