Atopic dermatitis is a multifactorial chronic disease that poses a great burden for patients and society. In recent
decades the prevalence has increased substantially in many countries, notably in Western societies, and the causes for this
increase are not completely understood. There are still many unanswered questions regarding atopic dermatitis with respect
to aetiology, pathophysiology, co-morbidity as well as subgrouping and treatment of the disease. Establishment of
the Danish Atopy Database (DAD), a cohort with ongoing inclusion of outpatients with atopic dermatitis from a tertiary
referral centre, allows the study of these aspects of the disease. Herein we present our methodological considerations in
regards to establishment of this cohort.