Risk Of Fatal Anaphylaxis Research Articles

Peanut Allergy: New Advances and Ongoing Controversies.

Peanut allergy is one of the most common food allergies in children, with increasing prevalence over time. The dual-allergen exposure hypothesis now supports transcutaneous sensitization to peanut as a likely pathophysiologic mechanism for peanut allergy development. As a result, there is emerging evidence that early peanut introduction has a role in peanut allergy prevention. Current first-line diagnostic tests for peanut allergy have limited specificity, which may be enhanced with emerging tools such as component-resolved diagnostics. Although management of peanut allergy includes avoidance and carrying an epinephrine autoinjector, risk of fatal anaphylaxis is extremely low, and there is minimal risk related to cutaneous or inhalational exposure. Quality of life in children with peanut allergy requires significant focus. Moving forward, oral and epicutaneous immunotherapy are emerging and exciting tools that may have a role to play in desensitization to peanut.

Oral immunotherapy for food allergy: mechanisms and role in management.

With the emergence of food allergy as an important public health problem, it has become clear that there is an unmet need in regard to treatment. In particular, IgE-mediated food allergy that is associated with risk of fatal anaphylaxis has been the subject of multiple studies in the past decade. The growing body of evidence derived from multiple centres and various study designs indicates that for IgE-mediated food allergy, immunomodulation through food immunotherapy is possible; however, the extent of protection afforded by such treatment is highly variable. At this time, the capacity for food immunotherapy to restore permanent tolerance to food has not been demonstrated conclusively. This review will discuss these topics as they apply to the most important studies of food oral immunotherapy.

Food allergy education: teen learning preferences

Background Food allergic teens are at increased risk for fatal anaphylaxis [1]. Food allergy education is needed to address the transition of care from their parents to the teens. Teen input into education approaches is essential in order to effectively develop programs that will modify behavior. Allergy educators will need to be familiar with effective approaches to education for this important population.

Risky business? Whether a more accurate picture of risk assessment in food allergic children and young people affects behaviours in school nurses and school first aiders

Background The risk of fatal anaphylaxis in a food allergic person is very low, yet the possibility of this catastrophic event is a major focus for both patients and healthcare professionals. It is unclear how healthcare professionals perceive risk of fatal or non-fatal anaphylaxis in the context of food allergy, and whether their perception of risk influences their management of food allergy. We investigated whether school nurses/first aiders could accurately estimate fatal anaphylaxis risk in children/young people with food allergy, and whether their assessment of risk correlated with their knowledge and management of food allergy in children/young people. Methods Interview-based surveys completed in 30 schools over 6 months included assessment of risk perception in relation to childhood food allergy using a novel risk assessment tool, an assessment of their knowledge of when to administer adrenaline and assessment of their practical ability to use an adrenaline autoinjector. Results Risk perception varied widely but all participants overestimated fatal food anaphylaxis risk more than they overestimated all-cause mortality risk in young people [median log-fold overestimate for all-cause mortality 0.51 (IQR 0.00, 1.48); food anaphylaxis death 1.20 (IQR 0.06, 2.10) p=0.018]. We did not find any association between estimation of anaphylaxis/fatal anaphylaxis risk in a food allergic child, and practical ability to use an adrenaline autoinjector in a simulated scenario. We did however find that participants who state that they would (unnecessarily) dial emergency services for a non-anaphylactic reaction, also significantly overestimated risk of anaphylaxis in a food allergic person (median log-fold overestimate 1.76 (IQR 0.92, 2.33) vs. 0.72 (IQR -1.51, 1.59) for those who would not dial emergency services for a non-anaphylactic reaction (p=0.009). Multivariate analyses showed weak evidence that personal or previous medical experience of allergic disease correlates with increased overestimation of fatal food anaphylaxis risk. Conclusion School nurses/first aiders overestimate fatal food anaphylaxis risk more than overestimating other fatality risks in children. The data suggests that this overestimation of risk is not associated with improved ability to recognise/manage anaphylaxis. These data suggest that correcting any risk misperception among healthcare providers, in relation to risk of anaphylaxis in food allergy, is unlikely to be harmful.

Platelet-Activating Factor, PAF Acetylhydrolase, and Severe Anaphylaxis

Vadas P, Gold M, Perelman B, et al. N Engl J Med. 2008;358(1):28–35 PURPOSE OF THE STUDY. To characterize the roles of platelet-activating factor (PAF) and PAF acetylhydrolase, the enzyme that inactivates PAF, in humans. STUDY POPULATION. The population was a variety of pediatric and adult patients with different levels of allergic disease along with nonallergic controls. METHODS. Serum PAF levels and activity of PAF acetylhydrolase were measured in 41 patients with anaphylaxis and in 23 control patients. Serum PAF acetylhydrolase activity was also measured in 9 patients with peanut allergy who had fatal anaphylaxis and compared with that in 26 nonallergic pediatric control patients, 49 nonallergic adult control patients, 63 children with mild peanut allergy, 24 patients with nonfatal anaphylaxis, 10 children who died of nonanaphylactic causes, 15 children with life-threatening asthma, and 19 children with non–life-threatening asthma. RESULTS. Mean serum PAF levels were significantly higher in patients with anaphylaxis than in patients in the control groups and were correlated with the severity of anaphylaxis. The proportion of subjects with elevated PAF levels increased from 4% in the control groups to 20% in the group with grade 1 anaphylaxis, 71% in the group with grade 2 anaphylaxis, and 100% in the group with grade 3 anaphylaxis. There was an inverse correlation between PAF levels and serum PAF acetylhydrolase activity. The proportion of patients with low PAF acetylhydrolase activity increased with the severity of anaphylaxis. Serum PAF acetylhydrolase activity was significantly lower in patients with fatal peanut anaphylaxis than in control patients. CONCLUSIONS. Serum PAF levels were directly correlated and serum PAF acetylhydrolase activity was inversely correlated with the severity of anaphylaxis. PAF acetylhydrolase activity was significantly lower in patients with fatal anaphylactic reactions to peanuts than in patients in any of the control groups. Failure of PAF acetylhydrolase to inactivate PAF may contribute to the severity of anaphylaxis. REVIEWER COMMENTS. PAF is 1 of the proinflammatory mediators that are released systemically by the degranulation of mast cells and basophils. Although PAF is not the only mediator that plays a role in anaphylaxis, these results suggest that PAF is very important. Therefore, it may be useful to develop new pharmaceutical agents that block its actions. Additional research is also needed to determine if PAF and PAF acetylhydrolase measurements may be used as a screening tool to select patients at highest risk for fatal anaphylaxis.

Épidémiologie de l’anaphylaxie pré-létale et létale

Anaphylaxis, a systemic reaction affecting two or more organs or systems, is due to the release of active mediators from mast cells and basophils. Anaphylactic reactions are usually classified on a four-grade scale, severe reactions corresponding to grades 3 (prelethal) and 4 (lethal). Here we present some recent fatal cases and then consider epidemiological studies reported during the past six years. Allergic emergencies account for from 0.2 to 1% of patients coming to Emergency Services. Severe anaphylaxis is estimated to be present in from 0.01 to 0.09% of these cases, with the highest rates being reported from the USA and Australia. The risk of fatal anaphylaxis is estimated to be from 0.65 to 2% of all cases of anaphylaxis, except in the case of children, where it is reported to be 0.0002% at most. These data are open to debate for several reasons. For example, individual programs for children at risk for food-induced anaphylaxis were registered in 0.065% of French school children. Thirty-one percent of the cases of severe anaphylaxis reported to the Allergo-Vigilance network in 2002 occurred in children. As regards peri-anesthesia anaphylaxis, 65% of the 518 proven cases of anaphylaxis reported over the past two years were grade 3 or 4. Nevertheless, the incidence of fatal anaphylaxis during general anesthesia is not documented. Moreover, the risk of severe anaphylaxis cannot be predicted by the past history of immediate reactions. However, based on the number of prescriptions of injectable epinephrine written for up to 0.95% of Canadians, the incidence of fatal anaphylaxis may be overestimated. On the other hand, it might be underestimated, since the diagnosis of food allergy, drug allergy, hymenoptera allergy and latex allergy is rarely carried out in such cases. Prospective, multicenter studies should be organized. Classification of the cases of anaphylaxis based on the four grades, and the CIM 10 code (ICD), should be used more widely to improve the precision of the data. Collaboration between Emergency Service personnel and allergists should be encouraged, with the aim of reducing the high level (30%) of undiagnosed anaphylaxis.