The most important contact sensitizers in Polish children and adolescents with atopy and chronic recurrent eczema as detected with the extended European Baseline Series.

The differential diagnostic work-up of children with chronic eczema should involve patch testing, also in cases with confirmed atopy. In our previous study, contact allergy was detected in every second child with chronic eczema. The aim of the present study was to identify the most important sensitizers in atopic children with eczema. During an allergy screening program, 103 consecutive children aged 7-8 and 93 adolescents aged 16-17 were enrolled. The inclusion criterion was chronic recurrent eczema as detected with the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire and atopy, defined as positive skin prick test to one or more common airborne or food allergens. The children were patch-tested with the newly extended European Baseline Series (EBS, 28 test substances) supplemented with propolis, thimerosal, benzalkonium chloride, and 2-phenoxyethanol. In total, 67.0% children and 58.1% adolescents were found patch test positive. Among children, 35.9% reacted to nickel, 16.5% propolis, 11.7% thimerosal, 9.7% cobalt, each 6.8% fragrance mix (FM) I and chromium, and 5.8% to FM II. Among adolescents, 37.6% reacted to thimerosal, 19.4% to nickel, 6.5% to cobalt, and 5.4% to propolis. We demonstrate the advantage of using FM II - a new addition to the EBS that detects a relatively high proportion of contact hypersensitivity among children. An important sensitizer from outside EBS is propolis, which according to the frequency of sensitization occupies rank 2 in children and rank 4 in adolescents. These data show that propolis should be included into routine patch testing in children.