Montreal—Patients diagnosed with anaphylaxis of an unknown cause tend to be treated inconsistently and suboptimally compared with those with an established diagnosis, according to a new study.
The study, published in The Journal of Allergy and Clinical Immunology: In Practice, followed nearly 4,000 cases of anaphylaxis seen in Canadian emergency departments from 2011 to 2018. McGill University–led researchers point out that surprising little is known about anaphylaxis due to an unknown trigger (AUT), even though it is an unpredictable and potentially fatal allergic reaction that is almost impossible to prevent through avoidance.
“In our study, 7.5 percent of the anaphylaxis cases were due to an unknown cause, and we found that the treatment and follow-up of AUT were suboptimal and inconsistent both inside and outside of the hospital,” explained lead researcher Moshe Ben-Shoshan, MD, MSc, a pediatric allergist and immunologist at the Research Institute of the McGill University Health Centre (RI-MUHC), and the Montreal Children’s Hospital of the MUHC.
“Specifically, epinephrine was underused and antihistamines were the primary treatment drug for AUT: 46 percent of patients in our study received antihistamines before arriving at the hospital and 55 percent of patients received antihistamines in the hospital emergency department,” Ben-Shoshan said.
The study is part of a larger national project and database, the Cross-Canada Anaphylaxis Registry (C-CARE), which tracks the rates, triggers, and management of anaphylaxis in different provinces and settings throughout Canada.
An unexpected finding of the research was that nearly one-fifth of patients with AUT were not prescribed an epinephrine autoinjector and that adults were even less likely to receive such a prescription than children.
Furthermore, the study team notes, just more than half of the patients, 56%, were referred to an allergist, although that was rare in the case of adults. Allergists were able to identify the cause of the severe allergy attack in 38% of those cases, according to the report.
The study recruited 295 AUT cases (7.5%) among 3,922 cases of anaphylaxis. In the prehospital setting. More likely to receive treatment with epinephrine were children (adjusted odds ratio [aOR], 1.20; 95% CI, 1.05-1.37) and those with a known food allergy (aOR, 1.14; 95% CI, 1.02-1.28.).
The study found that children were also more likely to be assessed by an allergist after their reaction (aOR, 1.43; 95% CI, 1.13-1.81) and were more likely to have an identified trigger for their reaction (aOR, 1.35; 95% CI, 1.07-1.70).
Among patients contacted for follow-up, food was identified as the cause of a reaction in 11 of 76 patients, while a new food allergy was diagnosed in four patients—two children and two adults.
“The underuse of epinephrine and the low rates of referral to an allergist, mainly in adults with AUT, highlight the need for clear guidelines and educational programs for diagnosis and management,” noted first author Michelle Le, a medical student at McGill University. “The important takeaway from this study is that there are significant discrepancies in treatment and follow up of patients with AUT that must be addressed in order to ensure prompt and appropriate management of anaphylaxis.”
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The study, published in The Journal of Allergy and Clinical Immunology: In Practice, followed nearly 4,000 cases of anaphylaxis seen in Canadian emergency departments from 2011 to 2018. McGill University–led researchers point out that surprising little is known about anaphylaxis due to an unknown trigger (AUT), even though it is an unpredictable and potentially fatal allergic reaction that is almost impossible to prevent through avoidance.
“In our study, 7.5 percent of the anaphylaxis cases were due to an unknown cause, and we found that the treatment and follow-up of AUT were suboptimal and inconsistent both inside and outside of the hospital,” explained lead researcher Moshe Ben-Shoshan, MD, MSc, a pediatric allergist and immunologist at the Research Institute of the McGill University Health Centre (RI-MUHC), and the Montreal Children’s Hospital of the MUHC.
“Specifically, epinephrine was underused and antihistamines were the primary treatment drug for AUT: 46 percent of patients in our study received antihistamines before arriving at the hospital and 55 percent of patients received antihistamines in the hospital emergency department,” Ben-Shoshan said.
The study is part of a larger national project and database, the Cross-Canada Anaphylaxis Registry (C-CARE), which tracks the rates, triggers, and management of anaphylaxis in different provinces and settings throughout Canada.
An unexpected finding of the research was that nearly one-fifth of patients with AUT were not prescribed an epinephrine autoinjector and that adults were even less likely to receive such a prescription than children.
Furthermore, the study team notes, just more than half of the patients, 56%, were referred to an allergist, although that was rare in the case of adults. Allergists were able to identify the cause of the severe allergy attack in 38% of those cases, according to the report.
The study recruited 295 AUT cases (7.5%) among 3,922 cases of anaphylaxis. In the prehospital setting. More likely to receive treatment with epinephrine were children (adjusted odds ratio [aOR], 1.20; 95% CI, 1.05-1.37) and those with a known food allergy (aOR, 1.14; 95% CI, 1.02-1.28.).
The study found that children were also more likely to be assessed by an allergist after their reaction (aOR, 1.43; 95% CI, 1.13-1.81) and were more likely to have an identified trigger for their reaction (aOR, 1.35; 95% CI, 1.07-1.70).
Among patients contacted for follow-up, food was identified as the cause of a reaction in 11 of 76 patients, while a new food allergy was diagnosed in four patients—two children and two adults.
“The underuse of epinephrine and the low rates of referral to an allergist, mainly in adults with AUT, highlight the need for clear guidelines and educational programs for diagnosis and management,” noted first author Michelle Le, a medical student at McGill University. “The important takeaway from this study is that there are significant discrepancies in treatment and follow up of patients with AUT that must be addressed in order to ensure prompt and appropriate management of anaphylaxis.”
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