D2.74 - Patterns of Contact Allergen Co-sensitization and polysensitization in children with suspected Allergic Contact Dermatitis

Allergic contact dermatitis is increasingly recognized in the pediatric population, yet data on patterns of allergen co-sensitization and polysensitization remain limited. Patch testing using the European Standard Battery (ESB) is a key diagnostic tool for identifying relevant allergens and understanding sensitization profiles in children. This study aimed to describe the frequency and patterns of co-sensitization and polysensitization to ESB allergens in children evaluated for suspected contact dermatitis.

This is a retrospective descriptive epidemiological study including all records of children aged 1 to 18 years who underwent patch testing with the European Standard Battery (ESB) in a Dermato-Allergology unit over a 10-year period.

A total of 120 medical records of children aged 1 to 18 years were reviewed. The mean age of the study population was 11.69 ± 4.53 years, ranging from 2 to 18 years, with a clear female predominance (63%). The prevalence of contact sensitization among the children was 42.5%. Co-sensitization to two ESB allergens was observed in 12 children, accounting for 23.5% of positive patch tests. The most frequent associations involved potassium dichromate and cobalt in 4 cases (7.84%), followed by chloro-methyl-isothiazolinone and methyl-isothiazolinone in 2 cases (3.92%). Polysensitization, defined as sensitization to three or more ESB allergens, was identified in 18 children (35.3% of positive tests). The most commonly observed allergen combinations included potassium dichromate, cobalt and nickel (2 cases; 3.92%), chloro-methyl-isothiazolinone, methyl-isothiazolinone and fragrance mix (2 cases; 3.92%), potassium dichromate, mercapto mix and mercaptobenzothiazole (2 cases; 3.92%), and colophony, fragrance mix and chloro-methyl-isothiazolinone (2 cases; 3.92%).

Our findings highlight a high rate of co-sensitization and polysensitization to ESB allergens in children with suspected allergic contact dermatitis. These results underscore the importance of comprehensive patch testing in the pediatric population to ensure accurate diagnosis, guide avoidance strategies, and improve long-term disease management.