Pediatric patch testing in a multi-ethnic Asian population: A retrospective review

Pediatric allergic contact dermatitis (ACD) is increasingly prevalent. Patch testing is the gold-standard diagnostic investigation. The aims of our study were to describe the clinical profile of pediatric patients with ACD in a multi-ethnic Asian population and identify the common contact allergens.

This was a retrospective study involving children and adolescents aged 16 years or younger with clinically suspected ACD who underwent patch testing between January 2007 and March 2020 at two institutions in Singapore. Information pertaining to their demographics, atopy history, clinical presentation, and patch test results was analyzed.

A total of 252 patients were included. The mean age was 10.9 years (1.0-16.7 years). The majority were Chinese (79.8%) and girls (57.5%). Many (66.3%) had atopic dermatitis (AD), which was mild. The most common presentation was an acral eczematous rash. The sensitization rate was 50.0%. The most frequent reactions were to nickel sulfate (49.2%) and fragrance mix (19.1%). The overall rate of relevant positive patch tests was 72.5%. Patients with AD were less likely to have a reaction to fragrance mix (p = .019) and more likely to have a reaction to disperse blue (p = .041). Compared to younger children, adolescents were less likely to have a positive patch test (p = .008). Indians were also less likely to have a positive reaction (p = .004).

Metals and fragrances were the most common allergens causing childhood ACD in Singapore. Patients with AD were less likely to be sensitized to fragrances and more likely to be sensitized to disperse blue dye.