Introduction
Non-steroidal anti-inflammatory drugs (NSAIDs) and other eicosanoid pathway modifiers are one of the most frequently used anti-inflammatory medications worldwide against infections, other acute and chronic inflammatory diseases and pain. Eicosanoids, including prostaglandins (PGs), leukotrienes (LTs), thromboxanes (TXs), hydroxyeicosatetraenoic acids (HETEs), lipoxins (LXs), and many recently proposed pro-resolving mediators constitute a wide range of active lipid mediators possessing pro- and anti-inflammatory, as well as pro-resolution properties.1 They are products of the major unsaturated fatty acids: arachidonic acid (AA), dihomo-γ-linolenic acid (DHGLA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA), metabolized in three main pathways: cyclooxygenase (COX), lipoxygenase (LO or LOX) and cytochrome P450 (Fig. 1) . Those active lipid mediators play substantial roles in the development and resolution of inflammation, including allergic and viral inflammation, which we have reviewed extensively in the previous report.1 Even though NSAIDs and other eicosanoid pathway modifiers are so commonly consumed and are relatively safe for the majority of people, the current pandemic of the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) revealed substantial knowledge gaps in understanding their modes of action, benefits and risks related to their use in patients with respiratory and allergic diseases. Unfortunately, this resulted in the conflicting messages sent to the public from the scientific community. Therefore, we, the European Academy of Allergy and Clinical Immunology Task Force (EAACI TF) on Eicosanoids, here critically review the most recent findings on the roles of NSAIDs, leukotriene antagonists (LTRAs), prostaglandin D2 (PGD2) receptor antagonists and cannabinoids, as well as we summarize their selectivity, and additional modes of actions in allergic airway diseases, drug allergy and respiratory virus infections. In addition, we also describe here the effects of novel T2 biologicals used in allergic diseases on eicosanoid pathways.