Contact sensitization in children and adolescents: Trends from a multicentre European study (2011-2022)

Contact allergy is a clinically relevant condition already present in early childhood, yet longitudinal European data remain scarce. This updated ESSCA analysis (2011-2022) offers the most comprehensive pediatric patch test dataset to date, enabling comparison with the previous 2002-2010 ESSCA study.

Standardized patch test data from 6961 children and adolescents (1-16 years) across 11 European countries was analyzed retrospectively. Sensitization rates, age distribution, allergen patterns, and associations with atopic dermatitis were assessed.

Contact sensitization was identified in 29.3% of children and adolescents, similar to the 28.9% reported in 2015. The youngest children (1-5 years) showed an unexpectedly high sensitization rate (34.3%). Across age groups, sensitization to nickel sulfate and methylisothiazolinone (MI) was higher among children aged 1-5 years (19.7% and 4.2%, respectively) compared with adolescents aged 13-16 years (7.3% and 3.2%). Similarly, cobalt chloride sensitization was lower in the oldest group (4.3%) than in the youngest (13.1%). Sensitization to 2-hydroxyethyl methacrylate (HEMA) was 1.4% in children aged 1-5 years and 0.7% in adolescents aged 13-16 years. Moreover, adolescents (13-16 years) exhibited a threefold increase in sensitization to para-phenylenediamine (PPD) compared to the 6-12-year age group. Notably, nickel positivity was highest in the northeast (27.2%) and lowest in the western region (e.g., UK, 6.6%), reflecting regional differences in product exposure.

Contact allergy remains common in the pediatric population but reveals evolving sensitization profiles shaped by regulation and societal change. Sensitization to nickel and acrylates was higher in the youngest children compared to adolescents, whereas PPD sensitization was higher in adolescents. Younger children showed the highest overall prevalence, and regional differences persist. These findings highlight the need for ongoing surveillance and periodic updates to pediatric patch test series to inform prevention and public health strategies.