Incidence of fatal food anaphylaxis in people with food allergy: a systematic review and meta-analysis

BACKGROUND: Food allergy is a common cause of anaphylaxis, but the incidence of fatal food anaphylaxis is not known. The aim of this study was to estimate the incidence of fatal food anaphylaxis for people with food allergy and relate this to other mortality risks in the general population. METHODS: We undertook a systematic review and meta-analysis, using the generic inverse variance method. Two authors selected studies by consensus, independently extracted data and assessed the quality of included studies using the Newcastle-Ottawa assessment scale. We searched Medline, Embase, PsychInfo, CINAHL, Web of Science, LILACS or AMED, between January 1946 and September 2012, and recent conference abstracts. We included registries, databases or cohort studies which described the number of fatal food anaphylaxis cases in a defined population and time period and applied an assumed population prevalence rate of food allergy. RESULTS: We included data from 13 studies describing 240 fatal food anaphylaxis episodes over an estimated 165 million food-allergic person-years. Study quality was mixed, and there was high heterogeneity between study results, possibly due to variation in food allergy prevalence and data collection methods. In food-allergic people, fatal food anaphylaxis has an incidence rate of 1.81 per million person-years (95%CI 0.94, 3.45; range 0.63, 6.68). In sensitivity analysis with different estimated food allergy prevalence, the incidence varied from 1.35 to 2.71 per million person-years. At age 0–19, the incidence rate is 3.25 (1.73, 6.10; range 0.94, 15.75; sensitivity analysis 1.18–6.13). The incidence of fatal food anaphylaxis in food-allergic people is lower than accidental death in the general European population. CONCLUSION: Fatal food anaphylaxis for a food-allergic person is rarer than accidental death in the general population

Patients’ ability to treat anaphylaxis using adrenaline autoinjectors: a randomized controlled trial

BACKGROUND: Previous work has shown patients commonly misuse adrenaline autoinjectors (AAI). It is unclear whether this is due to inadequate training, or poor device design. We undertook a prospective randomized controlled trial to evaluate ability to administer adrenaline using different AAI devices. METHODS: We allocated mothers of food‐allergic children prescribed an AAI for the first time to Anapen or EpiPen using a computer‐generated randomization list, with optimal training according to manufacturer's instructions. After one year, participants were randomly allocated a new device (EpiPen, Anapen, new EpiPen, JEXT or Auvi‐Q), without device‐specific training. We assessed ability to deliver adrenaline using their AAI in a simulated anaphylaxis scenario six weeks and one year after initial training, and following device switch. Primary outcome was successful adrenaline administration at six weeks, assessed by an independent expert. Secondary outcomes were success at one year, success after switching device, and adverse events. RESULTS: We randomized 158 participants. At six weeks, 30 of 71 (42%) participants allocated to Anapen and 31 of 73 (43%) participants allocated to EpiPen were successful – RR 1.00 (95% CI 0.68–1.46). Success rates at one year were also similar, but digital injection was more common at one year with EpiPen (8/59, 14%) than Anapen (0/51, 0%, P = 0.007). When switched to a new device without specific training, success rates were higher with Auvi‐Q (26/28, 93%) than other devices (39/80, 49%; P < 0.001). CONCLUSIONS: AAI device design is a major determinant of successful adrenaline administration. Success rates were low with several devices, but were high using the audio‐prompt device Auvi‐Q

Can we identify patients at risk of life-threatening allergic reactions to food?

Anaphylaxis has been defined as a “severe, life-threatening generalized or systemic hypersensitivity reaction”. However, data indicate that the vast majority of food-triggered anaphylactic reactions are not life-threatening. Nonetheless, severe life-threatening reactions do occur, and are unpredictable. We discuss the concepts surrounding perceptions of severe, life-threatening allergic reactions to food by different stakeholders, with particular reference to the inclusion of clinical severity as a factor in allergy and allergen risk management. We review the evidence regarding factors which might be used to identify those at most risk of severe allergic reactions to food, and the consequences of misinformation in this regard. For example, a significant proportion of food-allergic children also have asthma, yet almost none will experience a fatal food-allergic reaction; asthma is not, in itself, a strong predictor for fatal anaphylaxis. The relationship between dose of allergen exposure and symptom severity is unclear. While dose appears to be a risk factor in at least a subgroup of patients, studies report that individuals with prior anaphylaxis do not have a lower eliciting dose than those reporting previous mild reactions. It is therefore important to consider severity and sensitivity as separate factors, as a highly sensitive individual will not necessarily experience severe symptoms during an allergic reaction. We identify the knowledge gaps which need to be addressed to improve our ability to better identify those most at risk of severe foodinduced allergic reactions

World allergy organization anaphylaxis guidance 2020

Anaphylaxis is the most severe clinical presentation of acute systemic allergic reactions. The occurrence of anaphylaxis has increased in recent years, and subsequently, there is a need to continue disseminating knowledge on the diagnosis and management, so every healthcare professional is prepared to deal with such emergencies. The rationale of this updated position document is the need to keep guidance aligned with the current state of the art of knowledge in anaphylaxis management. The World Allergy Organization (WAO) anaphylaxis guidelines were published in 2011, and the current guidance adopts their major indications, incorporating some novel changes. Intramuscular epinephrine (adrenaline) continues to be the first-line treatment for anaphylaxis. Nevertheless, its use remains suboptimal. After an anaphylaxis occurrence, patients should be referred to a specialist to assess the potential cause and to be educated on prevention of recurrences and self-management. The limited availability of epinephrine auto-injectors remains a major problem in many countries, as well as their affordability for some patients

How does dose impact on the severity of food-induced allergic reactions, and can this improve risk assessment for allergenic foods?

Quantitative risk assessment for food allergens has made considerable progress in recent years, yet acceptability of its outcomes remains stymied because of the limited extent to which it has been possible to incorporate severity as a variable. Reaction severity, particularly following accidental exposure, depends on multiple factors, related to the allergen, the host and any treatments which might be administered. Some of these factors are plausibly still unknown. Quantitative risk assessment shows that limiting exposure through control of dose reduces the rates of reactions in allergic populations, but its impact on the relative frequency of severe reactions at different doses is unclear. Food challenge studies suggest that the relationship between dose of allergenic food and reaction severity is complex even under relatively controlled conditions. Because of these complexities, epidemiological studies provide very limited insight into this aspect of the dose-response relationship. Emerging data from single-dose challenges suggest that graded food challenges may overestimate the rate of severe reactions. It may be necessary to generate new data (such as those from single dose-challenges) to reliably identify the effect of dose on severity for use in quantitative risk assessment. Success will reduce uncertainty in the susceptible population and improve consumer choice

2015 update of the evidence base:World Allergy Organization anaphylaxis guidelines

The World Allergy Organization (WAO) Guidelines for the assessment and management of anaphylaxis provide a unique global perspective on this increasingly common, potentially life-threatening disease. Recommendations made in the original WAO Anaphylaxis Guidelines remain clinically valid and relevant, and are a widely accessed and frequently cited resource. In this 2015 update of the evidence supporting recommendations in the Guidelines, new information based on anaphylaxis publications from January 2014 through mid- 2015 is summarized. Advances in epidemiology, diagnosis, and management in healthcare and community settings are highlighted. Additionally, new information about patient factors that increase the risk of severe and/or fatal anaphylaxis and patient co-factors that amplify anaphylactic episodes is presented and new information about anaphylaxis triggers and confirmation of triggers to facilitate specific trigger avoidance and immunomodulation is reviewed. The update includes tables summarizing important advances in anaphylaxis research. Keywords: Anaphylaxis, Epinephrine, Auto-injector, Food allergy, Stinging insect venom allergy, Drug allergy, Latex allergy, Exercise-induced anaphylaxis, Systemic allergic reaction, Adrenalin

Anxiety, stress and risk perception in mothers of food allergic children

Background: Food allergy is a common chronic condition, affecting up to 10% of infants. Food allergy can occasionally cause anaphylaxis which is sometimes fatal. The risks of fatal or non-fatal anaphylactic reactions in childhood food allergy have not been quantified previously. Anxiety in the mothers of children with food allergy is increased, and it is unclear whether this is associated with misperception of risk of fatal and non-fatal anaphylaxis. Methods: I undertook a systematic review of published data to quantify the risk of fatal and non-fatal anaphylactic reactions to food, in children and adults with food allergy. Secondly a cross sectional survey of mothers of children attending an inner city hospital was carried out, to assess anxiety in the mothers and children, recruited from three groups: those with food allergy, asthma and hospital attendees without chronic illness. Results: The risk of fatal food anaphylaxis was low at one every 100 000 person years for food allergic adults and children. The risk of non-fatal anaphylaxis was higher and varied between 1 every 10 person years for self-reported anaphylaxis and 1 episode every 1000 person years reactions that required hospital admissions. In the cross-sectional survey we assessed 40, 18 and 38 mothers of food allergic, asthmatic, and no chronic illness (controls) children respectively. Mothers of food allergic children showed increased state anxiety and stress than controls. In regression analysis previous anaphylaxis (p=0.008) and poorly controlled asthma (p=0.004) as well as maternal social class were associated with increased maternal anxiety. Child anxiety and adjustment did not differ between food allergic and control groups. Mothers of food allergic children estimated the risk of fatal food anaphylaxis as greater than reality but estimated risk of death from any cause as less than reality. There was no correlation between risk estimation for fatal food anaphylaxis and measures of maternal anxiety/stress Conclusion: The risk of fatal food anaphylactic reactions for food allergic people is very low. In this study mothers of children with food allergy over-estimated this risk and displayed significantly increased anxiety and stress compared with mothers of children with no chronic illness, but risk estimation was not associated with anxiety. The theoretical and clinical implications are discussed.Open Acces

A brief psychological intervention for mothers of children with food allergy can change risk perception and reduce anxiety: Outcomes of a randomized controlled trial.

BACKGROUND: Mothers of children with food allergy have increased anxiety, which may be influenced by healthcare professionals' communication of risk. OBJECTIVE: To evaluate a brief psychological intervention for reducing anxiety in mothers of children with food allergy. METHODS: Two hundred mothers of children with food allergy were recruited from allergy clinics. A computer-generated randomization list was used to allocate participants to a single-session cognitive behavioural therapy intervention including a risk communication module, or standard care. Anxiety and risk perception were assessed at 6 weeks and 1 year. Primary outcome was state anxiety at 6 weeks. Secondary outcomes included state anxiety at 1 year, risk perception at 6 weeks and 1 year, and salivary cortisol response to a simulated anaphylaxis scenario at 1 year. RESULTS: We found no significant difference in the primary outcome state anxiety at 6 weeks, with mean 31.9 (SD 10.2) intervention, 34.0 (10.2) control; mean difference 2.1 (95% CI -0.9, 5.0; P=.17). There was significantly reduced state anxiety at 6 weeks in the intervention group, in the subgroup of participants with moderate/high anxiety at enrolment (103/200, 52%), with mean 33.0 (SD 9.3) intervention, 37.8 (SD 10.0) control; mean difference 4.8 (95% CI 0.9, 8.7; P=.016; Cohen's d effect size 0.50). The psychological intervention also reduced risk perception and salivary cortisol response (P=.032; effect size 0.36). CONCLUSION: We found evidence that a brief psychological intervention which incorporates accurate risk information may impact on anxiety, risk perception and physiological stress response in mothers of children with food allergy