IGHE and chronic idiopathic urticaria: The secretion of preformed mediators (e.g. histamine) and de novo synthesis of lipid mediators (e.g. leukotriene C4, prostaglandin D2) and various cytokines following FcεRI cross-linkage plays key roles in diverse IgE-mediated allergic conditions, including atopic dermatitis (AD) (23), chronic spontaneous urticaria (CSU) (24, 25), asthma (5, 26, 27), allergic rhinitis (28), food allergies (29), and anaphylaxis (30–32).