A 49-year-old male patient was referred to our clinic with a history of severe anaphylaxis (urticaria, angioedema, dyspnea, and hypotension) after a honeybee sting. Sensitization to apis mellifera was confirmed with both skin prick test and serum specific IgE and conventional IT for apis mellifera (Alutard SQ, ALK-Abelló, Hørsholm, Denmark) was initiated. Five minutes after the injection of 0.4-mL dose of the 4th vial (100,000 SQ units/mL) in the buildup phase, he developed anaphylaxis (flushing, itching, shortness of breath, and nausea). One week later, IT was continued with 0.1 mL of the 4th vial. An anaphylaxis episode similar to the previous one developed 5 minutes after the dose of 0.4 mL of the 4th vial in the patient whose IT dose was being increased 0.1 mL every week. This time the 3rd vial was started 1 week later by decreasing it by 0.6 mL. A systemic reaction similar to the previous one developed again at a dose of 0.4 mL of the 4th vial in our case who was continued IT at doses increased by 0.1 mL every week. We decided to combine IT with omalizumab 150 mg/2-week treatment due to these reactions. The omalizumab dosing scheme with b-VIT is not standardized and various dosing schedules have been used []. The scheme administered to our case is shown in . With IT + omalizumab combination, he was able to tolerate the buildup doses with which he had experienced anaphylaxis previously, and the maintenance dose (1 mL of the 4th vial) was reached. Omalizumab was discontinued and no reaction was observed with the maintenance dose administered 1 month later. However, after the maintenance dose of the 2nd month symptoms of itching, urticaria, cough, and dyspnea developed within 15 minutes. Adrenaline 0.5 mg intramuscular (IM) twice with an interval of 5 minutes, diphenhydramine 45.5 mg (Avil, Sandoz Ilac Sanayii A.S., Istanbul, Turkey) IM and methylprednisolone 40 mg (Prednol, Mustafa Nevzat Ilac Sanayii A.S., Istanbul, Turkey) intravenous were administered. Two weeks later, 150 mg of omalizumab was administered first and IT was administered 4 hours later by decreasing the dose to 0.4 mL of 4th vial. A reaction similar to the previous one occurred about half an hour after this dose. Patients who experienced significant bee anaphylaxis and have recurrent anaphylaxis episodes with b-VIT, must be evaluated regarding basal serum tryptase levels and mastocytosis []. The basal serum tryptase level was 63 ng/mL in our case (reference range < 11.5 ng/mL). The case had no mastocytosis skin findings and no history of chronic itching or urticaria. He did not describe a history of anaphylaxis with another allergen. The patient refused to be undergone bone marrow biopsy. Both IT and omalizumab treatments were terminated. Protection measures and how to use an epinephrine auto-injector were explained again.
A 51-year-old female with c-kit-positive ISM and tryptase 31.8 ng/ml () reported intermittent episodes of shortness of breath, chest tightness, abdominal pain, and diarrhea. She had generalized lesions of urticaria pigmentosa involving her entire body, although numerous on her lower extremities. Ketotifen and ranitidine failed to control the symptoms. Omalizumab injections were started at 300 mg every two weeks (). At follow-up, her shortness of breath and chest tightness were controlled and GI symptoms had improved. Furthermore, her urticaria pigmentosa had improved and was now only observed on the lower abdomen and upper thighs. After the fourth cycle of omalizumab, she experienced an immediate multisystem reaction with respiratory distress and tongue swelling. A fifth cycle was attempted but again resulted in a similar reaction, leading to discontinuation of omalizumab therapy. At follow-up, she reported a worsening respiratory and functional status as well as 3-4 loose bowel movements per day. Basal tryptase levels had increased up to 41.2 ng/ml ().