Introduction-The etiology of atopic dermatitis (AD) is multifactorial with interaction between genetics, immune and environmental factors.Areas covered-We review the role of prenatal exposures, irritants and pruritogens, pathogens, climate factors, including temperature, humidity, ultraviolet radiation, outdoor and indoor air pollutants, tobacco smoke exposure, water hardness, urban vs. rural living, diet, breastfeeding, probiotics and prebiotics on AD.Expert commentary-The increased global prevalence of AD cannot be attributed to genetics alone, suggesting that evolving environmental exposures may trigger and/or flare disease in predisposed individuals. There is a complex interplay between different environmental factors, including individual use of personal care products and exposure to climate, pollution, food and other exogenous factors. Understanding these complex risk factors is crucial to developing targeted interventions to prevent the disease in millions. Moreover, patients require counseling on optimal regimens for minimization of exposure to irritants and pruritogens and other harmful exposures.

We recommend using these strata for interpretation of their respective measures in clinical trials of AD. There are important differences between the five assessments, which profoundly impact the interpretation of their scores.

Active and passive exposure to smoke are associated with increased AD prevalence.

Skin pain is a common and burdensome symptom in AD. Skin pain severity should be assessed with itch severity in AD patients and may be an important end point for monitoring treatment response.

Self-reported adult-onset AD is common and has distinct phenotypes with lesional predilection for the hands and/or head/neck.