Atopic dermatitis (AD) and psoriasis affect a substantial percentage of the population. The mechanisms of disease, endotypes, co-morbidities of these diseases remain poorly understood. There is need to define the heterogeneous and homogeneous aspects of AD and psoriasis and identify the impact of environmental factors, genetic factors and molecular pathways. This will give rise to more precise targeted treatments. The BIOMAP project will bring together existing resources from European cohorts and industry to meet this challenge. ALSPAC, with it's rich longitudinal phenotyping and molecular data is well suited to contribute to this project.