Environmental Exposures: Evolving Evidence for Their Roles in Adult Allergic Disorders

Kaoru Harada; Rachel L. Miller


Curr Opin Allergy Clin Immunol. 2022;22(1):24-28. 

In This Article

Abstract and Introduction


Purpose of Review: Allergic disorders are the result of complex interactions between genetic predisposition and environmental exposures. Elucidating how specific environmental exposures contribute to allergic diseases in adults is crucial, especially as the world population ages in a rapidly changing environment.

Recent Findings: The effects of environmental exposures on allergic diseases remain understudied in adults. Although epidemiological studies suggest various environmental exposures are associated with the development and exacerbation of allergic diseases, further longitudinal studies are needed across various age groups in adults to pinpoint the exposures of concerns and the time windows of susceptibility. Mechanistic studies in adults are few. A multicomponent strategy targeting several allergens has been conditionally recommended for asthma, but recent findings on mitigation strategies remain limited.

Summary: Further research on how environmental exposures cause and exacerbate allergic disorders is needed in adults, particularly across disease phenotypes. The effects of mitigation strategies against environmentally induced adult allergic diseases remain large research gaps. A better understanding of how and which environmental exposures contribute to allergic disorders is necessary to identify patients who are at higher risk and would benefit from specific interventions.


The concept of the exposome, defined as the entire exposure from external and internal environments, has created a framework for considering how the totality of the environment contributes to the development and exacerbation of allergic disorders.[1] Studies in monozygotic twins have shown that genetic inheritance alone is an insufficient cause of many chronic diseases, including asthma.[2] Elsewhere, established genetic risk factors such as filaggrin mutations and effects of ancestry have been unable to explain the burden of atopic dermatitis past childhood.[3,4] These findings emphasize the importance of understanding how environmental exposures and other changing conditions interact with inherited genetic predisposition. Although great progress has been made on the importance of the prenatal and early childhood environment risk factors in childhood allergic disorders, the impact of environmental exposures remains understudied in adults. Evolving evidence will remain the focus of this review.[]