Incidence of allergic contact dermatitis in Finland 1998–2021: A nationwide registry‐based study

Abstract Background Allergic contact dermatitis (ACD) may be chronic and can cause distress, disability, and absence from work. Nationwide epidemiological studies of ACD are sparse. Objectives To use national registry data to study the incidence and aetiology of ACD in the working age population of Finland. Methods Patient records from the years 1998–2021 were obtained from the Finnish Care Register for Health Care. Study subjects aged 18–65 years were selected on the basis of a diagnosis of ACD. Results Total number of study subjects was 26 701. The incidence of ACD increased until 2016 after which it started to decrease. The increase was more marked in females and ACD was particularly common in women reporting reactions to cosmetics and other chemical products and in people of both sexes reacting to adhesives. The incidence ‘ACD of unspecific cause’ has decreased since 2016. The most commonly reported allergens were metals, followed by cosmetics. One fourth of subjects had ≥2 ACD diagnoses. Conclusions The incidence of ACD in working age subjects rose from 1998 to 2016, especially in females. However, the incidence has been decreasing since 2016. Our findings highlight the ongoing and even increasing burden of ACD among the working age population.