Latest news on contact allergies

In recent years, there have been important new developments in the diagnosis and research of contact allergies. An updated European guideline clarifies the performance and interpretation of patch testing and emphasizes the importance of testing based on medical history and exposure. At the same time, new exposures from nail cosmetics, three-dimensional (3D) printing resins, medical adhesives, medical devices, and new cosmetic active ingredients are leading to changes in the spectrum of relevant contact allergens. Our understanding of allergic contact dermatitis (ACD) has also expanded. Molecular and single-cell analyses show that ACD cannot be viewed solely as a classic type IV reaction, but rather that barrier alterations, innate immune responses, different T‑cell programs, and tissue-resident memory T‑cells interact. This minireview summarizes the clinically relevant new developments and discusses their significance for diagnosis and clinical practice.