IGHE and respiratory depression: Opioids may provoke respiratory depression [222] and ST [14] (Section 2) but are rarely involved in type I IgE antibody/FcεRI-mediated allergic responses although cutaneous wheal and flare reactions and some hemodynamic effects of histamine-releasing opioids such as morphine, codeine, and meperidine may lead to an anaphylactoid response and false diagnoses of an IgE-mediated reaction [8, 223–225].