At this point, a rapid release of pre-formed mediators occurs within minutes and newly synthesized ones within 15 min, resulting in the well-known effects of vasodilation, bronchoconstriction, and allergic inflammation, which characterize allergic rhinitis and asthma, food allergies, allergic reactions to venoms or medications, and more generally, IgE-mediated forms of urticaria-angioedema and anaphylaxis. This evidence concerns the gene IGHE and urticaria.