Patch Testing in Allergic Contact Dermatitis.

BACKGROUND: Allergic contact dermatitis is one of the most common forms of skin diseases that require medical intervention. Appropriate detection of allergens by patch test and accurate avoidance of them is the key to management. The objective of this study is to determine the types and frequency of allergens responsible for Allergic contact dermatitis in a tertiary hospital of Nepal. METHODS: Altogether 120 patients with Allergic contact dermatitis were enrolled in the study. Patch test was performed to find out the most common inciting allergen, utilizing the Indian Standard Series of allergens approved by The Contact and Occupational Dermatoses Forum of India. Results were read at 48 and 96 hours. Grading of the reactions was done based on the criteria of the International Contact Dermatitis Research Group. Pattern of reactivity of different allergens was assessed. RESULTS: Of all the patients, 63 (53%) showed positivity to at least one allergen. Nickel sulfate was the most frequent sensitizing agent in 22 (18%) cases, followed by Fragrance mix in 11(9%) and Paraphenylenediamine in 7 (6%) cases. Out of all positive results, Grade 1 positivity was seen in 44 (51%), Grade 2 positivity in 41(47%) and only 2 (2%) cases showed Grade 3 positivity. Mercaptobenzothiazole, Balsam of Peru, Nitrofurazone and Wool Alcohol did not show positive results in any of our patients. CONCLUSIONS: Patch testing helps in the treatment, long term remission, and patient counseling for prevention. Larger scale studies are required to know the sensitivity to allergens in Nepalese population.

Axillary Contact Dermatitis: An Update on Potential Allergens and Management.

The differential diagnosis of dermatoses in the axillae is broad. Contact dermatitis-both irritant and allergic-represents common etiologies. Axillary contact dermatitis can develop following exposure to a variety of irritants and/or allergens. Frequently implicated sources include deodorants, antiperspirants, detergents, soaps, and clothing. Fragrance, a ubiquitous ingredient within these products, as well as metals and dyes, are common causes of contact dermatitis. Clinical assessment, bedside diagnostic techniques, histopathology, and patch testing can aid in the diagnosis and help inform management directions.

Botanical Briefs: Contact Dermatitis Induced by Western Poison Ivy (Toxicodendron rydbergii).

"Leaves of three, leave it be" serves as an apt caution for avoiding poison ivy (Toxicodendron species) and its dermatitis-inducing sap. Toxicodendron contact dermatitis (TCD) poses a notable burden to the American health care system by accounting for half a million reported cases of allergic contact dermatitis (ACD) annually. Identifying and avoiding physical contact with the western poison ivy (Toxicodendron rydbergii) plant prevails as the chief method of preventing TCD. This article discusses common features of T rydbergii as well as clinical manifestations and treatment options following exposure to this allergenic plant.

Contact Allergy to Allergens in the Swedish Baseline Series Overrepresented in Diabetes Patients with Skin Reactions to Medical Devices - A Retrospective Study from Southern Sweden.

Allergic contact dermatitis is reported among individuals using continuous glucose monitoring systems and insulin pumps. The aim of this study was to describe contact allergy patterns for allergens in the Swedish baseline series and medical device-related allergens among users. Contact allergy to baseline series allergens and isobornyl acrylate was compared between diabetes patients and dermatitis patients patch-tested at the Department of Occupational and Environmental Dermatology during 2017 to 2020. Fifty- four diabetes patients and 2,567 dermatitis patients were included. The prevalence of contact allergy to fragrance mix II and sesquiterpene lactone mix was significantly higher in diabetes patients compared with dermatitis patients. Of the diabetes patients 13.0% and of the dermatitis patients 0.5% tested positive to sesquiterpene lactone mix (p < 0.001). Of the diabetes patients 7.4% and of the dermatitis patients 2.3% tested positive to fragrance mix II (p = 0.041). Of the diabetes patients 70.4% tested positive to medical device-related allergens. Of the diabetes patients 63.0% and of the dermatitis patients 0.2% were allergic to isobornyl acrylate (p < 0.001). In conclusion, not only medical device-related contact allergies, but also contact allergy to baseline series allergens (fragrance mix II and sesquiterpene lactone mix), is overrepresented in diabetes patients who use medical devices.

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.

New device, 'old' allergens. Allergic contact dermatitis caused by the Dexcom G7 glucose sensor.

BACKGROUND: Allergic contact dermatitis (ACD) has been reported as an adverse effect from the use of several glucose sensors and insulin pumps from different manufacturers. Isobornyl acrylate (IBOA) has been identified as a major culprit sensitizer, but also other acrylates and (modified) colophonium have been reported as causes of ACD. OBJECTIVES: To report the two first cases diagnosed with ACD caused by the Dexcom G7 (DG7) glucose sensor. PATIENTS AND METHODS: Two children with suspected ACD from DG7 were patch tested with our medical device series with an addition of selected test preparations including two variants of modified colophonium - methyl hydrogenated rosinate (MHR) and glyceryl hydrogenated rosinate (GHR). Both patients were also tested with acetone extracts made from different parts of the DG7 sensor. The extracts were analysed by gas chromatography-mass spectrometry (GC-MS). RESULTS: Both patients tested positive to IBOA, hydroabietyl alcohol and GHR. In addition, patient 1 had a positive reaction to MHR and patient 2 had a positive reaction to colophonium. The GC-MS analyses showed the presence of IBOA and colophonium-related substances in the DG7 extracts. CONCLUSIONS: Both patients were diagnosed with contact allergy to well-known medical device-related sensitizers. The presence of IBOA and (modified) colophonium in a newly introduced (on the Swedish market in 2023) glucose sensor is remarkable and indicates an inadequate toxicological assessment of the materials used in the sensor.

Allergic contact dermatitis due to 1,6-hexanediol diacrylate in ostomy patients.

BACKGROUND: Many people live with ostomies after life-saving surgery. Ostomy patients often suffer from peristomal dermatitis. Allergic contact dermatitis (ACD) has been reported, mostly due to contact allergy (CA) to topical agents. OBJECTIVES: We present three patients with therapy resistant peristomal dermatitis, suggesting ACD caused by different stoma products. METHODS: Patch testing was performed with baseline series, additional series, and selected allergens. They were also tested with their own ostomy products as is and separate extracts of the products. Extracts were analysed using Gas Chromatography-Mass Spectrometry (GC-MS). RESULTS: In all three patients we diagnosed CA to 1,6-hexanediol diacrylate (HDDA), +++ in case (C) 1 and 3, ++ in C 2. HDDA was detected in C 2's ostomy pouch adhesive and in C 1's and 3's flange extenders used to improve the adhesion of the ostomy pouches. CONCLUSION: Therapy resistant peristomal dermatitis should always be suspected of ACD and patch testing, especially with the patient's own products, should be performed.

[Translated article] Four-year Epidemiological Surveillance of the Spanish Registry of Research in Contact Dermatitis and Cutaneous Allergy: Current Situation and Trends.

BACKGROUND: The epidemiological surveillance of contact dermatitis is one of the objectives of the Spanish Registry of Research in Contact Dermatitis and Cutaneous Allergy. Knowing whether the prevalence of positive tests to the different allergens changes over time is important for this monitoring process. OBJECTIVES: To describe the various temporary trends in allergen positivity in the GEIDAC standard series from 2018 through December 31, 2022. METHODS: This was a multicenter, observational trial of consecutive patients analyzed via patch tests as part of the study of possible allergic contact dermatitises collected prospectively within the Spanish Registry of Research in Contact Dermatitis and Cutaneous Allergy. The data was analyzed using 2 statistical tests: one homogeneity test (to describe the changes seen over time) and one trend test (to see whether the changes described followed a linear trend). RESULTS: A total of 11327 patients were included in the study. Overall, the allergens associated with a highest sensitization were nickel sulfate, methylisothiazolinone, cobalt chloride, methylchloroisothiazolinone/methylisothiazolinone, and fragrance mix i. A statistically significant decrease was found in the percentage of methylisothiazolinone positive tests across the study years with an orderly trend. CONCLUSIONS: Although various changes were seen in the sensitizations trends to several allergens of the standard testing, it became obvious that a high sensitization to nickel, methylchloroisothiazolinone/methylisothiazolinone and fragrances mix i remained. Only a significant downward trend was seen for methylisothiazolinone.

2-Hydroxyethyl methacrylate (2-HEMA) sensitization, a global epidemic at its peak in Spain?

BACKGROUND: A global epidemic of allergic contact dermatitis to (meth)acrylates has been described in relation to the widespread use of manicure products. OBJECTIVES: To evaluate the frequency of sensitization to 2-hydroxyethyl methacrylate (2-HEMA) among consecutively patch tested patients with eczema in Spain; the percentage of current relevance; the MOAHLFA index; and, the potential sources of exposure to (meth)acrylates. METHODS: From January 2019 to December 2022, 2-HEMA 2% pet. was prospectively patch tested in 24 REIDAC (Spanish Allergic Contact Dermatitis Registry) centres. RESULTS: Six thousand one hundred thirty-four patients were consecutively patch tested with 2-HEMA 2% pet. 265/6134 (4.3%) were positive. Positive reactions of current relevance were identified to involve 184/265 (69%). The efficiency (number of patch tests needed to detect relevant positive patch test reactions) was 34 (6134/184). The variable 'occupational' was found to be significantly associated with a higher risk for relevant positive reactions to 2-HEMA (OR: 10.9; 95% CI: 8.1-14.9). CONCLUSION: (Meth)acrylate sensitization is a prevalent health issue in Spain. 2-HEMA 2% pet. has been identified to be a highly effective (meth)acrylate allergy marker in the GEIDAC baseline series. The responsible authorities should implement policies guaranteeing accurate labelling of industrial, medical, and consumer materials while ensuring the enforcement of said labelling through appropriate legal means.

Gene profiling in active dermatitis lesions strengthens the diagnosis of allergic contact dermatitis.

BACKGROUND: Distinguishing between allergic and nonallergic forms of Contact Dermatitis (CD) is challenging and requires investigations based on patch-testing. Early detection of allergy biomarkers in active CD lesions could refine and simplify the management of CD patients. OBJECTIVE: To characterize the molecular signatures of active CD lesions. METHODS: We studied the expression of 12 allergy biomarkers by qRT-PCR in active lesions of 38 CD patients. Allergic CD (ACD) was diagnosed based on patch test (PT) results and exposure assessment. Molecular signatures of active lesions, as well as positive PT reactions, were compared with those of reference chemical allergens and irritants. RESULTS: Nineteen of the 38 CD patients reacted positively upon patch-testing and exposure assessment confirmed ACD diagnosis for 17 of them. Gene profiling of active CD lesions revealed 2 distinct molecular patterns: patients harboring signatures similar to reference allergens (n = 23) or irritants (n = 15). Among the 23 patients with an "allergy signature," we found the 17 patients with confirmed ACD, while no culprit allergen was identified for the 6 other patients. Interestingly, the 15 patients without biomarker induction had negative PT, suggesting that they developed nonallergic CD reactions. CONCLUSION: Molecular signatures from active skin lesions may help to stratify CD patients and predict those suffering from ACD.

Tattoo-induced allergic contact dermatitis presents diagnostic challenge as a cellulitis mimic.

Allergic contact dermatitis (ACD) is a prevalent condition associated with numerous potential allergen exposures. Tattoo ink is variable and may contain allergens that can be overlooked in patient education and diagnosis. We present a 27-year-old female with ACD following a new tattoo. The patient was repeatedly misdiagnosed with cellulitis by three different clinicians and treated with multiple antibiotics without improvement. The correct diagnosis was eventually made in the emergency department (ED). Although the patient was aware of her allergies to nickel and cobalt from patch testing, she was not aware of the potential for tattoo ink to contain these allergens because prior tattoos had not provoked an allergic reaction. Consequently, the appropriate care was delayed by a month, resulting in significant morbidity. This case demonstrates the potential for ACD to present similarly to cellulitis in an ED setting and the need for clinical vigilance in diagnosis of ACD. It also highlights the importance of detailed patient education on potential allergen sources particularly in the context of tattooing, which is performed with unregulated and variable ink products.