ABSTRACT
Allergic diseases are common worldwide and have widespread implications in global health issues affecting children and adults. Allergic diseases, such as asthma, allergic rhinitis (hay fever), food allergies, and life-threatening insect sting reactions, are mediated by IgE antibodies directed against airborne, food, and insect venom allergens. In severe instances, life-threatening respiratory compromise or anaphylaxis can result in fatal outcomes. As the IgE-mediated response can be mounted almost instantaneously, the phenomenon is often referred to as “immediate hypersensitivity.” In this chapter, we discuss the mechanisms and clinical consequences of IgE-mediated hypersensitivity providing a mechanistic understanding and facilitating the translation of the immune process into its clinical manifestations. The discussion of laboratory diagnostic testing for IgE-mediated allergic processes provides the interface between the pathophysiology and the clinical expression of this immune process. The prototypical diseases—anaphylaxis, asthma, and food allergy—that arise from IgE-mediated responses will be discussed to exemplify how this immune mechanism results in common health issues. Finally, an overview of various approaches to treatment is included, with an emphasis on mechanisms of action that result in desired therapeutic outcomes.
