Atopy was not related to development of eczema or asthma in children under age 13 years, according to Ann-Marie Malby Schoos, Ph.D., and her associates at the University of Copenhagen.

Allergic sensitization increased with age in the 399 children tested, rising from 12% at 6 months to 54% at 13 years. The incidence of asthma was highest at age 4 years at 16%, but decreased afterward, falling to 12% at 13 years. The incidence of eczema peaked at 39% in children aged 1.5 years old, but decreased steadily to only 12% in 13-year-olds.

Asthma and allergic sensitization were related only in late childhood, with an odds ratio of 4.49 in 13-year-olds. This pattern was seen throughout allergic sensitization subgroups. There were strong associations between eczema and allergic sensitization at 6 months (OR, 6.02), 1.5 years (OR, 2.06), and 6 years (OR, 2.77), but no association at 13 years. The proportion of children with allergic sensitization who did not have asthma or eczema also increased with age.

“The tradition of using atopy as a particular endotype of asthma and eczema seems unfounded because it depends on the method of testing for sensitization, type of allergens, and age of the patient. This questions the relevance of the terms atopic asthma and atopic eczema as true endotypes,” the investigators concluded.

Find the full study in the Journal of Allergy and Clinical Immunology (doi: 10.1016/j.jaci.2015.10.004).