Contact hypersensitivity and allergic contact dermatitis among school children and teenagers with eczema.

BACKGROUND Patch testing is an essential procedure in the investigation of eczema in children. OBJECTIVES To analyse the frequency of contact hypersensitivity and allergic contact dermatitis among Polish children with eczema. PATIENTS/METHODS During an allergy screening programme involving 9320 children aged 7 and 16 years, 12.6% reported symptoms of chronic/recurrent eczema. From this group, a representative sample of 229 eczema children underwent patch testing: 96 children aged 7 years and 133 teenagers aged 16 years. Patch testing was with 10 allergens: methylchloroisothiazolinone/methylisothiazolinone (MCI/MI), nickel sulfate, mercury ammonium chloride, thimerosal, cobalt chloride, potassium dichromate, lanolin, fragrance mix I, Myroxylon pereirae (balsam of Peru), and colophonium. RESULTS 49.4% tested children were found patch test (PT) positive. 43.8% of 7 year olds with eczema were PT positive, with sensitization to nickel sulfate (30.2%), thimerosal (10.4%), cobalt chloride (8.3%), fragrance mix I (7.3%), MCI/MI (6.3%), potassium dichromate (6.3%), M. pereirae (3.1%), mercury ammonium chloride (2.3%), and colophonium (1.0%). 52.6% teenagers were PT positive, with sensitization to nickel sulfate (23.3%), thimerosal (27.8%), cobalt chloride (10.5%), potassium dichromate (6.0%), mercury ammonium chloride (2.3%), M. pereirae (1.5%), and MCI/MI (0.8%). The final diagnosis of allergic contact dermatitis was confirmed in 36% of 7 year olds and 26% of 16 year olds. CONCLUSIONS Every second child with eczema is PT positive, whereas every third child is finally diagnosed with allergic contact dermatitis.