Omalizumab and the World Health Organization. It is also used to treat people 12 years and above with chronic spontaneous urticaria (also called chronic idiopathic urticaria), which cannot be treated with elevated doses of H1-antihistamines. The main adverse effect is anaphylaxis (a life-threatening systemic allergic reaction), with a rate of occurrence of 1 to 2 patients per 1,000. Like other protein and antibody drugs, omalizumab also causes anaphylaxis, although at a relatively low frequency among antibody drugs. The allergic reaction is probably not due to the binding characteristics of the antibody drug, but to the protein nature of the antibody. The
Allergic transfusion reaction antihistamine and if the symptoms completely disappear and the patient feels well, the transfusion may be restarted. A mild transfusion reaction during infusion usually does not progress to a more severe anaphlyactic reaction after infusion of additional product from the same unit. If the symptoms are more than mild, the transfusion should not be restarted. There is no evidence that antihistamine premedication prevents allergic transfusion reactions, although these drugs can mitigate symptoms once they occur. Allergic transfusion reaction An allergic transfusion reaction is a blood transfusion that results in allergic reaction. It is among the most common transfusion reactions to