A Retrospective Review and Analysis of Systemic Reactions among Subcutaneous Aeroallergen Immunotherapy Patients

Abstract

RATIONALE: To ascertain the frequency of systemic reactions to immunotherapy and identify potential risk factors in our patient population.METHODS: We reviewed patient records from 1994-1997, characterized our patient population, and analyzed any reactions based on demographic, clinical, immunotherapy, and treatment parameters.RESULTS: Of the 201 patients receiving aeroallergen subcutaneous immunotherapy, 118 complete chart records involving 6,830 injections were reviewed. Eighty patients (68%) were female; 77 (65%) experienced a total of 630 reactions. There were no fatalities. Twenty one patients (18%) experienced a total of 34 systemic reactions for a systemic reaction rate of 0.49%. Of these, 16 (47%) occurred in the first year and 27 (79%) within the first two years; 7 reactions (20%) occurred during the buildup phase. Eleven reactions (32%) occurred with no prior reactions, while 15 reactions (44%) occurred within 3 months of a prior large local or systemic reaction. Systemic reactions were associated with higher number of injections received (P = 0.0001). Systemic reactors were less likely to be allergic to house dust mite (P = 0.01) and more likely to have a family history of asthma or angioedema. Asthma was almost twice as common among local reactors as compared with systemic reactors (P < 0.05).CONCLUSIONS: Nonfatal systemic reactions among our patient population occurred at a rate commensurate with published reports (0.05-3.2%, mean 0.5%). The only factor significantly associated with systemic reactions was the number of injections received. Prior local reactions were not predictive of systemic reactions. Aeroallergen immunotherapy remains a safe and effective means of treating allergic rhinitis in appropriately selected patients. RATIONALE: To ascertain the frequency of systemic reactions to immunotherapy and identify potential risk factors in our patient population. METHODS: We reviewed patient records from 1994-1997, characterized our patient population, and analyzed any reactions based on demographic, clinical, immunotherapy, and treatment parameters. RESULTS: Of the 201 patients receiving aeroallergen subcutaneous immunotherapy, 118 complete chart records involving 6,830 injections were reviewed. Eighty patients (68%) were female; 77 (65%) experienced a total of 630 reactions. There were no fatalities. Twenty one patients (18%) experienced a total of 34 systemic reactions for a systemic reaction rate of 0.49%. Of these, 16 (47%) occurred in the first year and 27 (79%) within the first two years; 7 reactions (20%) occurred during the buildup phase. Eleven reactions (32%) occurred with no prior reactions, while 15 reactions (44%) occurred within 3 months of a prior large local or systemic reaction. Systemic reactions were associated with higher number of injections received (P = 0.0001). Systemic reactors were less likely to be allergic to house dust mite (P = 0.01) and more likely to have a family history of asthma or angioedema. Asthma was almost twice as common among local reactors as compared with systemic reactors (P < 0.05). CONCLUSIONS: Nonfatal systemic reactions among our patient population occurred at a rate commensurate with published reports (0.05-3.2%, mean 0.5%). The only factor significantly associated with systemic reactions was the number of injections received. Prior local reactions were not predictive of systemic reactions. Aeroallergen immunotherapy remains a safe and effective means of treating allergic rhinitis in appropriately selected patients.