A 49-year-old woman was diagnosed with c-kit-positive ISM with tryptase 11.4 ng/ml (). Symptoms of SM included daily headaches, sporadic flushing, itchy throat, mild coughing, loose stools, lightheadedness, and palpitations. No cutaneous manifestations of mastocytosis were observed. She was markedly intolerant to exercise, heat, and strong emotion, all of which triggered the symptoms in spite of medications, which included ranitidine, loratadine, cetirizine, ketotifen, and montelukast. In early 2017, she experienced 5 anaphylactic reactions, requiring emergency department visits and treatment with epinephrine as well as 5 milder reactions managed at home (). Omalizumab was started at 300 mg at 4-week intervals (). On omalizumab, multisystem reactions were entirely suppressed, with only breakthrough flushing once per week, loose stools roughly twice per month, and occasional lightheadedness. A follow-up one year later revealed complete resolution of symptoms with no adverse reactions to her medications and reduced tryptase to 8.3 ng/ml ().
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.