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[Display omitted] The contribution of Staphylococcus aureus to the exacerbation of atopic dermatitis (AD) is widely documented, but its role as a primary trigger of AD skin symptoms remains poorly explored. This study sought to reappraise the main bacterial factors and underlying immune mechanisms by which S aureus triggers AD-like inflammation. This study capitalized on a preclinical model, in which different clinical isolates were applied in the absence of any prior experimental skin injury. The development of S aureus– induced dermatitis depended on the nature of the S aureus strain, its viability, the concentration of the applied bacterial suspension, the production of secreted and nonsecreted factors, as well as the activation of accessory gene regulatory quorum sensing system. In addition, the rising dermatitis, which exhibited the well-documented AD cytokine signature, was significantly inhibited in inflammasome adaptor apoptosis-associated speck-like protein containing a CARD domain– and monocyte/macrophage-deficient animals, but not in T- and B-cell–deficient mice, suggesting a major role for the innate response in the induction of skin inflammation. However, bacterial exposure generated a robust adaptive immune response against S aureus , and an accumulation of S aureus– specific γδ and CD4+ tissue resident memory T cells at the site of previous dermatitis. The latter both contributed to worsen the flares of AD-like dermatitis on new bacteria exposures, but also, protected the mice from persistent bacterial colonization. These data highlight the induction of unique AD-like inflammation, with the generation of proinflammatory but protective tissue resident memory T cells in a context of natural exposure to pathogenic S aureus strains. [ABSTRACT FROM AUTHOR]

Introduction La méthylisothiazolinone (MI) est un conservateur utilisé depuis 2005 dans notre quotidien. Peu après son introduction, de nombreux cas d’allergie ont été répertoriés. Il existe un véritable problème concernant l’éviction de cet allergène ubiquitaire pour les populations sensibilisées. Peu d’études se sont intéressées au devenir des patients. L’objectif de cette étude est d’évaluer l’évolution à long terme des patients après le diagnostic d’allergie à la MI. Méthodes Notre étude reprend rétrospectivement l’ensemble des patients sensibilisés à la MCI/MI et MI entre 2010 et 2015, au CHU de Clermont-Ferrand. Les caractéristiques de l’eczéma étaient répertoriées pour chaque patient. À travers un questionnaire téléphonique, nous avons interrogé ces mêmes patients sur le nombre de rechutes et leur gestion depuis le diagnostic d’eczéma de contact. Nous avons discuté les difficultés d’éviction, l’information retenue et les améliorations à apporter à nos pratiques professionnelles. Résultats Au total, 98 patients d’âge moyen de 40 ans avaient des tests positifs pour la MI, 73 % étaient des femmes, 31 % étaient atopiques et 58 % poly sensibilisés. Un total de 46 patients ont répondu au questionnaire. Parmi les rechutes, 8 étaient sévères et 23 non sévères ou chroniques. Au total, 6/8 avaient une atteinte des mains, 5/8 patients avaient identifié un produit responsable, tous les patients avaient un terrain atopique. Et, 4/8 patients jugeaient leur attitude d’éviction bonne, les 4 autres plutôt moyenne ou faible. Discussion Les caractéristiques démographiques des patients, les localisations cliniques, les produits sources retrouvés sont en accord avec les données de la littérature. Des plaques d’eczéma persistent chez la moitié des patients malgré une attitude d’éviction correcte, cependant, on ne peut exclure le rôle d’effets confondants (atopie, dermite d’irritation, autres sensibilisations allergiques). Les rechutes sévères sont néanmoins peu fréquentes. Les patients semblent satisfaits de la prise en charge. Les perspectives d’amélioration résident dans un suivi dermatologique, un projet d’éducation personnalisé ou collectif, et des rappels d’information. [ABSTRACT FROM AUTHOR]

Background: Methylisothiazolinone (MI) is a preservative that is responsible for an epidemic of allergic contact dermatitis (ACD). Few studies have been published on the prognosis of patients with MI-induced ACD., Objectives: To evaluate relapses of MI-induced ACD and difficulties in avoiding MI in patients who had received avoidance advice., Methods: A retrospective study of patients with MI-induced ACD diagnosed in two specialized dermato-allergology units between 2010 and 2015 was performed. The median follow-up was 3 years., Results: Relapses were observed in 64% of 139 included patients, and were severe in 18%. Rinse-off cosmetics were responsible for the largest proportion of relapses (27%). The median time to relapse was 5 months. Sixty-nine per cent of relapses were on the hands, and 29% were on the face. Risk factors for relapsing were hand eczema and a personal history of atopy. The main difficulties encountered in the avoidance strategy were hidden sources of MI, the lack of labelling on industrial products, the complexity of cosmetic labelling, and remembering the name of the allergen., Conclusion: MI-induced ACD has a poor prognosis. Its high rate of relapse is mainly attributable to the difficulties of avoidance. Management needs to be improved. Specialized follow-up in the year following diagnosis is essential to educate patients., (© 2019 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: Hair bleaching is increasingly being carried out in hairdressing salons. The products used are a mixture of hydrogen peroxide and persulfates, both active chemical agents. Scalp burns secondary to hair bleaching are a traumatic adverse effect rarely discussed in publications that continue to be little known among healthcare professionals., Patients and Methods: We report the case of a 15-year-old girl with a plaque of scarring alopecia on the vertex. This lesion resulted from a deep burn following a hair-bleaching procedure. Healing took around 4 months, resulting in discomfort for our patient., Discussion: This is a rare case of scarring alopecia following a basic chemical burn to the scalp. The oxidation reaction induced by the mixture of hydrogen peroxide and persulfates, prepared in a basic medium, causes bleaching of the melanin pigments in hair. The clinical presentation of a single, well limited, painful, oozing ulceration located at the vertex was similar to the other cases published in the literature. Although a chemical burning mechanism is most often incriminated, the procedure is always coupled with use of a heat source and associated thermal burn may occur. The delayed appearance of the lesion appears to be caused by the forming of surfactants by the hydrogen peroxide/persulfate mixture, resulting in slow dissolution of the oxidizing compounds within the stratum corneum., (Copyright © 2018 Elsevier Masson SAS. All rights reserved.)