Contact Sensitization and Polysensitization in a Tertiary Referral Cohort of Children With Moderate-To-Severe Atopic...

Children with atopic dermatitis (AD) demonstrate increased susceptibility to contact sensitization (CS) due to epidermal barrier dysfunction and chronic cutaneous inflammation. However, the frequency and patterns of contact sensitization in paediatric AD remain incompletely defined.

To evaluate the frequency of CS in a selected tertiary referral cohort of children with AD, and to assess associations with age, disease severity, and topographic phenotypes.

In this cross-sectional study, 54 children (≤ 18 years) with AD underwent standardized patch testing using a modified paediatric baseline series. Reactions graded +, ++, or +++ were considered positive, whereas doubtful and irritant reactions were excluded. Polysensitization was defined as positivity to ≥ 3 allergens. Associations between sensitization status, topographic distribution (head and neck, trunk, palmo-plantar), and disease severity were analysed using Fisher's exact test and Mann-Whitney U test, as appropriate.

CS was identified in 49/54 patients (90.7%), while polysensitization was observed in 27/54 children (50.0%). The most frequent allergens were nickel sulphate and cobalt chloride, each detected in 17 patients (31.5%), followed by potassium dichromate in 15 patients (27.8%) and propolis in 13 patients (24.1%). Among polysensitized patients, propolis sensitization was identified in 40.7%, with propolis and cobalt representing the most frequent co-sensitization pattern. Exploratory analysis of the five most frequent allergens showed no statistically significant associations with topographic phenotypes. Furthermore, neither contact sensitization nor polysensitization burden demonstrated significant associations with age and disease severity.

Our findings support consideration of patch testing in children with moderate-to-severe AD, regardless of their age, disease severity, and topographic phenotype.