SKIN ALLERGY: Edited by Thomas Werfel and Torsten ZuberbierHighlights in allergic contact dermatitis 2018/2019Johansen, Jeanne D.a; Werfel, Thomasb Author Information aDepartment of Dermatology and Allergy, National Allergy Research Centre, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark bKlinik für Dermatologie, Allergologie und Venerologie und Forschungsabteilung Immundermatologie und exp. Allergologie, Medizinische Hochschule Hannover, Hannover, Germany Correspondence to Jeanne D. Johansen, DMSc, Professor, Consultant, Department of Dermatology and Allergy, National Allergy Research Centre, Gentofte Hospital, University of Copenhagen, 2900 Hellerup, Denmark. Tel: +45 38677301; e-mail: [email protected] Current Opinion in Allergy and Clinical Immunology: August 2019 - Volume 19 - Issue 4 - p 334-340 doi: 10.1097/ACI.0000000000000552 Buy Metrics Abstract Purpose of review The purpose was to highlight recent findings especially concerning new and old allergens, trends, diagnosis and causes of contact allergy. Recent findings Nickel is still the most frequent cause of contact allergy in women and piercings remain an important risk factor. Countries with a long history of regulation of contact allergens have the lowest level of contact allergy to nickel and chromium in Europe. Among the most frequent causes of fragrance contact allergy is terpenes, which are oxidized such as limonene, linalool and in some countries: geraniol. Methylisothiazolinone is still causing considerable problems due to hidden exposures. Acrylates are emerging allergens and 2-hydroxyethyl methacrylate has been included in the 2019 update of the baseline series, as many new cases are seen due to long-lasting nail polish based on acrylates and glue (isobornyl acrylate) in insulin pumps. More than 10 new allergens have been described, which need to be considered in diagnosing contact allergy. Summary Allergic contact dermatitis is a frequent problem, it also constitutes a challenge to diagnose due to many potential contact allergens. The main culprit allergens remain the same, new significant causes are found especially within acrylates. Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.