CD18 Prevalence of allergic contact dermatitis in the paediatric population: a 6-year retrospective review of two patch testing centres

Abstract Allergic contact dermatitis (ACD) in children and adolescents is an important diagnosis that can cause significant morbidity. They are a distinct cohort from the adult population due to exposure to different allergens. In cases where a relevant result is identified, avoiding the allergen can be a simple and effective management. Children are patch tested in fewer numbers than adults and it is likely that the prevalence of ACD in this population is underestimated. Potential reasons for this may be perceived difficulties in children tolerating testing, and the high prevalence of atopic eczema in children, which has a similar presentation to ACD. All paediatric patients undergoing patch testing over a 6-year period (January 2019 to December 2024) in two specialist cutaneous allergy centres were included in this retrospective review. Relevant data were extracted from patch test departmental records and electronic notes. Patch test readings were performed on day 2 and day 4 in accordance with the International Contact Dermatitis Research Group and European Society of Contact Dermatitis guidelines. In total, 240 patients were included (70 male, 170 female), with an average age of 13 years at the time of patch testing (age range 3–17 years). Overall, 75% (179) had a personal history of atopy. The most common hobbies were the gym, swimming, football, gaming, netball, piano, and arts and crafts. One-quarter (25%, 61) of patients asked had been exposed to one or more potentially ‘risky behaviours’ (hair dye: 27, artificial nails: 41, black henna tattoo: 31), with the youngest exposed aged 10 years. In total, 47% (112) presented with facial dermatitis, most localized to periorbital or perioral areas or both. Overall, 18% (44) presented with hand dermatitis and 7% (17) were referred to investigate a specific trigger such as sunscreen. Patch testing was positive in 50% (120) of patients. Of those with a positive reaction 67% (79) had a history of atopy. In patients with multiple positive patch tests 93% (37 of 40) were atopic. Positive relevant allergens are categorized in the Table, with the most common allergens listed. Our results highlight the importance of patch testing in atopic and nonatopic children. The most common relevant causes of paediatric ACD in our cohort were fragrance, preservatives, metals and lanolin.TableThe most common currently relevant allergens in paediatric patients (n = 120)Fragrances38% (45)Linalool19% (18)Fragrance mix I7% (8)Balsam of Peru6% (7)Limonene5% (6)Preservatives31% (37)MI12% (14)MCI/MI10% (12)Metals10% (12)Nickel6% (7)Wool alcohols10% (12)Acrylates9% (10)Medicaments9% (10)Rubber7% (8)Carba mix 3%4% (5)Sunscreens4% (5)MCI, methylchloroisothiazolinone; MI, methylisothiazolinone.