Published Online: July 27, 2014
Anaphylaxis is a severe, potentially life-threatening systemic allergic reaction, which occurs suddenly after a person comes in contact with an allergy-causing substance, such as food, insect venom, or medication. Past studies have suggested that older age, the use of multiple medications, and the presence of comorbid medical conditions are the main risk factors for severe anaphylaxis. These previous studies, however, were small, used varying definitions of anaphylaxis, and often compared individuals that experienced severe anaphylaxis to those who experienced only mild allergic reactions.
In an article recently published in The Journal of Allergy & Clinical Immunology (JACI), Clark and colleagues analyze data from 11,972 commercially insured US patients who visited the Emergency department (ED) or were hospitalized for anaphylaxis. The authors identified anaphylactic events using the Harduar-Morano algorithm. They further focused their study on individuals in the sample who experienced severe anaphylaxis, which the authors define as a reaction that required hospital admission. Their primary aim was to examine demographic and clinical characteristics and healthcare utilization in the year before the index event to identify risk factors for a severe anaphylaxis event.
Consistent with previous studies, the authors found older age and presence of comorbidities to be significant risk factors for severe anaphylaxis. Furthermore, they found that individuals who had a severe anaphylactic reaction were less likely to have filled a prescription for an epinephrine auto-injector (EAI) or to have visited an allergist or immunologist in the year before the index event. Interestingly, these individuals were more likely to have had an earlier ED visit or hospitalization. Even after experiencing a severe anaphylactic reaction, these individuals were less likely to fill an EAI prescription or to see an allergist/immunologist. The authors also report that concomitant medication use was significantly associated with severe anaphylaxis independent of age.
This study highlights the importance of preventive anaphylaxis care for avoiding severe anaphylactic reactions. The patients who were being monitored by an allergist/immunologist and who had access to an EAI may have been better able to recognize their symptoms and to use their EAI before seeking medical attention and before the reaction progressed. Improvement in discharge instructions may also be warranted to encourage patients to see an allergist after severe anaphylaxis.
The Journal of Allergy and Clinical Immunology (JACI) is an official scientific journal of the AAAAI, and is the most-cited journal in the field of allergy and clinical immunology.