Background2‐Hydroxyethyl methacrylate (HEMA) was added to the European baseline series (EBS) in 2019. Few recent data are available on the frequency and relevance of positive reactions to this hapten.ObjectivesTo investigate the frequency and relevance of positive patch tests to HEMA in the EBS in a university hospital in Amsterdam, The Netherlands.Patients and MethodsRetrospective study in patients with positive patch tests to HEMA investigated between June 2019 and August 2023.ResultsOf 2927 consecutive patients, 88 (79 women and 9 men; 3.0%) had a positive reaction to HEMA. The prevalence in women was 3.9%, in men 1.0%. Forty‐three (49%) reactions were judged to be of current clinical relevance and 21 (24%) of past relevance. In this group of 64 patients with relevant reactions, 18 (28%) had occupational contact with (meth)acrylate‐containing products, of who 11 (61%) were nail stylists. In 46 patients with non‐occupational allergic contact dermatitis, 31 (67%) had allergic reactions to nail cosmetics. Glues and glue‐containing products accounted for 22% of the materials causing allergic contact dermatitis and dental products for 8%.ConclusionsAllergic reactions to HEMA are very frequent in women investigated in Amsterdam. Nearly two thirds of cases were caused by nail cosmetics.