Contact allergy in children with and without atopic dermatitis: An Italian multicentre study

Background Contact allergy and atopic dermatitis (AD) are both common inflammatory T cell-mediated diseases and many factors may influence the prevalence of contact allergy in AD patients. In children, their possible correlation was debated with conflicting results. Objectives The present study aimed to assess the prevalence of contact sensitivity in children and to investigate the association with AD. Materials and methods A retrospective multicentre study on children aged from 0 to 14 years patch tested between January 2017 and December 2018 was performed. Children were consecutively patch tested with the SIDAPA (Societa Italiana Dermatologia Allergologica Professionale Ambientale) baseline series. Results Among the 432 children investigated for contact allergy, 125 (28.9%) showed a positive reaction to at least one of the allergens tested, with a higher prevalence of positive patch test reactions in girls (32.3%) than in boys (25.0%). The most frequent contact allergens were nickel sulphate (10.2%), cobalt chloride (6.7%), methylisothiazolinone (3.7%), fragrance mix-2 (3.2%), potassium dichromate (2.8%), fragrance mix-1 (2.1%) and methylchloroisothiazolinone/methylisothiazolinone (2.1%). One-hundred-three children (23.8%) suffered from AD showing a higher prevalence of positive patch test (36.9%) compared to children without AD (26.4%). Conclusions Despite the topic being still controversial, the present study suggests a consistent prevalence of contact allergy among children with higher sensitivity rate among children with AD than without AD.