Highlights in allergic contact dermatitis 2018/2019.

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.