This review highlights advances in mechanisms of allergic disease, particularly type 2 innate lymphoid cells; TH2 lymphocytes; eicosanoid regulation of inflammation; extracellular vesicles in allergic responses; IL-33; microbiome properties, especially as they relate to mucosal barrier function; and a series of findings concerning the allergic inflammatory cells eosinophils, basophils, and mast cells. During the last year, mechanistic advances occurred in understanding type 2 innate lymphoid cells, particularly related to their response to ozone, involvement with experimental food allergy responses, and regulation by IL-33. Novel ways of regulating TH2 cells through epigenetic regulation of GATA-3 through sirtuin-1, a class III histone deacetylase, were published. The understanding of eicosanoid regulation of inflammation increased and focused on additional properties of phospholipase A2 and the role of prostaglandin D2 and its receptors and inhibitory prostaglandin E2 pathways. Mechanisms through which extracellular vesicles are released and contribute to allergic responses were reported. There was a deeper appreciation of mucosal barrier function, the epithelial alarmin IL-33, and the microbiome. Finally, there were advances concerning allergic inflammatory cells (mast cells, basophils, and eosinophils) that will undoubtedly have an effect on disease understanding and new therapeutic strategies.