An Overview of Adherence-What It Is and Why It Is Important.

Asthma, allergic rhinitis, and food allergy are common allergic diseases, yet adherence to many management options remains poor, leading to worse health outcomes and financial implications for society and health systems. The underlying causes of nonadherence are numerous, ranging from patient-specific factors to broader socioeconomic and systems-based factors. In this review, we aim to discuss the definition of adherence, which can be divided into 3 components: initiation, implementation, and persistence, as well as to review various methods of measuring adherence. Subsequently, we will review the epidemiology of adherence to asthma and allergic rhinitis medications, allergen immunotherapy, and oral immunotherapy. Finally, we will discuss the multifaceted etiology of poor adherence and its subsequent impact on patients and society.