China
Africa
Explore chapters and articles related to this topic
Extraction and Chemistry of Rubber Allergens
Published in Robert N. Phalen, Howard I. Maibach, Protective Gloves for Occupational Use, 2023
Standardized analytical assays are available for measurement of latex protein, antigens, and allergens from gloves and their use contributed to the reduction of cases of Type I glove-associated allergic reactions. Chemical analyses to extract, identify, and quantify residual chemical additives from rubber gloves are both complex and instrument intensive and while accelerator-free rubber gloves are available, Type IV rubber glove allergy remains a problem. Contact allergen patch testing of rubber glove allergens suggests that residual thiuram allergy is still prevalent, although chemical analyses of gloves for thiurams are usually negative. This in part can be explained by reduction of thiurams to ZDTCs and formation of other mixed disulfides during the vulcanization process, cross-reactivity with ZDTCs, and potential for oxidation of ZDTCs back to thiurams during glove use.
Topical Contact Immunotherapy in Alopecia Areata
Published in Rubina Alves, Ramon Grimalt, Techniques in the Evaluation and Management of Hair Diseases, 2021
Andrea Combalia, Juan Ferrando
Moreover, the therapeutic effect of topical immunotherapy is independent from a specific substance. Any potent contact allergen could be used, but for obvious reasons common allergens have to be excluded. Therefore, when choosing a sensitizer, it should not be present in the natural or industrial environment of humans.
Monographs of fragrance chemicals and extracts that have caused contact allergy / allergic contact dermatitis
Published in Anton C. de Groot, Monographs in Contact Allergy, 2021
The SCCS (Scientific Committee on Consumer Safety), in a 2012 Opinion on Fragrance allergens in cosmetic products, has marked 3-methyl-5-(2,2,3-trimethyl-3-cyclopentenyl)pent-4-en-2-ol as ‘established contact allergen in humans’ (1,4).
Framework for sensitization assessment of extractables and leachables in pharmaceuticals
Published in Critical Reviews in Toxicology, 2022
Patricia Parris, Geraldine Whelan, Anders Burild, Jessica Whritenour, Uma Bruen, Joel Bercu, Courtney Callis, Jessica Graham, Esther Johann, Troy Griffin, Martin Kohan, Elizabeth A. Martin, Melisa Masuda-Herrera, Brad Stanard, Eric Tien, Maureen Cruz, Lee Nagao
The mechanism of skin (Type IV) sensitization is fundamental to the ELSIE Sensitization Assessment Framework. It has been well-described and is shown in Figure 1. A contact allergen has initial exposure to the skin and may be metabolized, covalently binding to proteins present. Allergens or haptens may then pass through the epidermis and induce a localized immune response, through activation of keratinocytes resulting in cytokine secretion. Antigen presenting cells (APC, for example Langerhans cells or dendritic cells in the skin) then take up the allergen and process it into small peptides, which can be displayed on the cell surface. Next, the APCs migrate to lymph nodes, draining from the site of exposure. In the lymph node, they interact and activate T cells which specifically recognize the peptides displayed. The activated antigen-specific T cells then proliferate, resulting in sensitization of an individual. Upon repeat exposure to the allergen, the expanded antigen-specific T cell population are recruited to the site of exposure and elicit an inflammation/immune response and allergic contact dermatitis.
Undeclared formaldehyde levels in patient consumer products: formaldehyde test kit utility
Published in Cutaneous and Ocular Toxicology, 2019
Jason E. Ham, Paul D. Siegel, Howard Maibach
Formaldehyde, the American Contact Dermatitis Society (ACDS) 2015 allergen of the year, can be found as a preservative/antimicrobial in many consumer and industrial products. Formaldehyde may be added directly to the product, or released through addition of formaldehyde-releasing agents. Many chemicals are capable of releasing formaldehyde. Some common releasers include 1,3-dimethylol-5,5-dimethylhydantoin (DMDM hydantoin), imidazolidinyl urea, diazolidinyl urea and Quaternium-15. Groot et al.1 identified 42 different formaldehyde releasers from the literature, but noted that for 7 in that list “the data are inadequate to label them as such beyond doubt”. In a recent study examining the prevalence of preservatives and reported rates of contact allergy using data derived from the Contact Allergen Management Program (CAMP) most of the formaldehyde releasers included in the search were among the top 20 preservatives found across all products2.
Best practices, new perspectives and the perfect emollient: optimizing the management of contact dermatitis
Published in Journal of Dermatological Treatment, 2018
Jean-Marie Lachapelle, Ana Gimenez-Arnau, Martin Metz, Jill Peters, Ehrhardt Proksch
Of note, the onset of ACD is also characterized by two distinct phases: sensitization and elicitation. Sensitization is observed following first exposure to a contact allergen, which nonspecifically activates keratinocytes to release inflammatory cytokines, leading to an influx of activated LCs to the site of allergen contact. Some antigen-presenting LCs move to the lymph nodes, where they active antigen-specific T cells. The activated T cells proliferate to form Th1 and Th17, which are subsequently released into the circulation and migrate to the dermis. Elicitation is observed if the same contact allergen penetrates the skin for a second time, stimulating antigen-specific memory T cells, leading to the recruitment of inflammatory cytokines and an allergic reaction (16). The reaction observed in ACD contrasts significantly with the modulatory response thought to be elicited when healthy skin with an intact barrier is exposed to a contact allergen. The immune-mediated reaction in ACD also contrasts to ICD, which can occur in any individual without prior sensitization.