[Severe anaphylaxis following administration of omalizumab].

A patient with chronic spontaneous urticaria (CSU) received treatment with the monoclonal antibody omalizumab, which resulted in significant clinical improvement but repeatedly triggered severe anaphylactic reactions. These occurred both after administration of the medication and during a prick test. The exact mechanisms behind the reactions are unclear; possible causes could include additives such as polysorbate 20 or specific antibodies. The case highlights the rare but serious risk of anaphylaxis with omalizumab and emphasizes the need for close monitoring and emergency preparedness.