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.