Do nut-free zones on airplanes make sense to you?

Madely Health Headlines Commentary for January 11, 2010

Source:

Air Canada ordered to create nut-free buffer zones

A CFRA web poll asked this question and I discussed this with Steve Madely. This is a continuation of our discussion from last week.

The incidence of fatal anaphylaxis from all causes is outlined in this report from Uptodate.com.

INCIDENCE — The annual incidence of fatal anaphylaxis is not known precisely. Estimates of anaphylactic deaths (from drugs, foods, insect stings, and latex) in the US has been estimated at .002 percent annually [14-16]. The UK has reported one case of fatal anaphylaxis per three million individuals yearly, or approximately 20 deaths a year over the past decade [17]. A study from New Zealand estimated the rate to be approximately 1 per one million [10]. Studies have drawn conflicting conclusions about whether the incidence of fatal anaphylaxis is increasing [3,18-20].

Medline ® Abstracts for References 14-16 of ‘Fatal anaphylaxis’

14

TI Anaphylaxis in the United States: an investigation into its epidemiology.

AU Neugut AI; Ghatak AT; Miller RL

SO Arch Intern Med 2001 Jan 8;161(1):15-21.

BACKGROUND: Anaphylaxis is a severe, life-threatening allergic reaction that affects both children and adults in the United States. However, data regarding the incidence and prevalence of anaphylaxis and the number of deaths caused by it are limited. OBJECTIVE: To provide a better understanding of the magnitude of the problem of anaphylaxis in the United States. METHODS: A thorough review of the current medical literature was conducted to obtain prevalence estimates on each of the 4 major subtypes of anaphylaxis (food, drugs, latex, and insect stings). We calculated an overall estimate of the risk of anaphylaxis by using only estimates that are specifically derived from epidemiologic studies measuring anaphylaxis in the general population. RESULTS: Known rates or cases of anaphylaxis were 0.0004% for food, 0.7% to 10% for penicillin, 0. 22% to 1% for radiocontrast media, and 0.5% to 5% after insect stings. There were 220 cases after latex exposure. Considering the 1999 US population of 272 million, the population at risk for anaphylaxis from food is 1099, from penicillin is 1.9 million to 27. 2 million, from radiocontrast media is 22 000 to 100 000, from latex is 220, and from insect stings is 1.36 million to 13.6 million. These calculations yield a total of 3.29 million to 40.9 million individuals at risk of anaphylaxis. CONCLUSION: The occurrence of anaphylaxis in the US is not as rare as is generally believed. On the basis of our figures, the problem of anaphylaxis may, in fact, affect 1.21% to 15.04% of the US population.

AD Department of Medicine, College of Physicians and Surgeons, Columbia University, 630 W 168th St, Room PH18-127, New York, NY 10032, USA. ain1@columbia.edu

PMID 11146694

15

TI Assessment of patients who have experienced anaphylaxis: a 3-year survey.

AU Yocum MW; Khan DA

SO Mayo Clin Proc 1994 Jan;69(1):16-23.

DESIGN: A quality-control retrospective review of medical records was conducted for cases of anaphylaxis encountered at Mayo Clinic Rochester during a 3 1/2-year period. PATIENTS: For inclusion in the study, all patients had to manifest general symptoms of mediator release such as generalized pruritus, urticaria, angioedema, and flushing. Of the 179 patients with anaphylaxis (mean age, 36 years), 66% were female, 49% had atopy, and 37% had a previous history of immediate reactions to allergens. Of these study patients, 11 were receiving medications capable of exacerbating anaphylaxis (beta-blockers in 7 of them). RESULTS: Consultation with an allergist was obtained in 142 cases, and a probable diagnosis was made after review of the medical records. Causes of anaphylaxis included foods in 59 patients, idiopathic in 34, Hymenoptera in 25, medications in 23, and exercise in 12; false-positive diagnoses were recorded in 18. Allergy prick tests were done in 104 patients, 71 of whom had positive results; allergen-specific IgE tests were done in 44 patients, 23 of whom had positive results. In 19 patients, only allergen-specific IgE testing was done, and results were positive in 12. Normal test results included C1 esterase inhibitor in 33 patients, metabisulfite challenge in 15, and dye or preservative challenge in 10. Food skin tests were graded on a relative value scale and revealed 15 highly allergic, 24 moderately allergic, and 39 weakly allergic food groups. CONCLUSION: A standard protocol should be used for assessment of patients with anaphylaxis, and fresh food extracts should be used for prick skin testing. A national incidence study of anaphylaxis is needed. The publicand school personnel should be educated about food anaphylaxis, and emergency treatment for anaphylaxis should be readily available for patients.

AD Division of Allergic Diseases and Internal Medicine, Mayo Clinic, Rochester, MN 55905.

PMID 7903730

16

TI Epidemiology of anaphylaxis in Olmsted County: A population-based study.

AU Yocum MW; Butterfield JH; Klein JS; Volcheck GW; Schroeder DR; Silverstein MD

SO J Allergy Clin Immunol 1999 Aug;104(2 Pt 1):452-6.

BACKGROUND: Awareness of the clinical features of anaphylaxis and its causative triggers is important if recurrent episodes are to be avoided. The incidence of anaphylaxis in the general population is often underreported, and epidemiologic studies are few. Because an accurate profile of anaphylaxis could heighten awareness of this problem, we investigated the epidemiology of anaphylaxis in the general population of Olmsted County, Minn. OBJECTIVE: The purpose of this study was to describe the epidemiology of anaphylaxis in Olmsted County residents from 1983 through 1987. METHODS: This was a retrospective population-based cohort study. The medical records of 1255 Olmsted County residents identified by computer-linked, medical diagnostic indices (the Rochester Epidemiology Study) were reviewed retrospectively to identify residents whose clinical episodes met the criteria for anaphylaxis. We determined the incidence and rate of occurrence of anaphylaxis, rate of recurrence, prevalence of atopy, cause of anaphylaxis, frequency of referral to an allergy specialist, hospital admission rate, and case-fatality rate. RESULTS: There were 133 residents who experienced 154 anaphylactic episodes during the 5-year period: 116 residents had 1 episode of anaphylaxis, 13 residents had 2 episodes, and 4 residents had 3 episodes. The anaphylaxis occurrence rate was 30 per 100,000 person-years (95% confidence interval, 25-35). There were 110 residents who had a first lifetime episode of anaphylaxis (that was medically evaluated) during the years 1983 to 1987. The average annual incidence rate of anaphylaxis was 21 per100,000 person-years (95% confidence interval, 17-25). Atopy was present in 53% of the cohort, and allergy consultation was obtained in 52%. A suspect allergen was identified in 68% of the cohort, most frequently a food, medication, or insect sting. The hospitalization rate was 7%, and 1 patient died. CONCLUSION: The incidence of anaphylaxis is less than 1%, and death rarely occurs. People with atopy experience anaphylaxis more frequently than people without atopy. Anaphylaxis frequently is not recognized by patients and physicians.

10452770

Medline ® Abstract for Reference 17 of ‘Fatal anaphylaxis’

17

TI Anaphylaxis: can we tell who is at risk of a fatal reaction?

AU Pumphrey R

SO Curr Opin Allergy Clin Immunol 2004 Aug;4(4):285-90.

PURPOSE OF REVIEW: Anaphylaxis is frightening and patients commonly fear their next reaction will be fatal. This review looks at the characteristics of fatal reactions to find if a fatal recurrence is predictable. RECENT FINDINGS: Most publications on fatal anaphylaxis are case reports that do not help predict risks. Most epidemiological studies focus on non-fatal reactions. The UK fatal anaphylaxis register demonstrates that over two-thirds of those dying from sting reactions and over four-fifths dying from drug anaphylaxis had no previous indication of their allergy, whereas those dying from food allergy had usually had previous reactions but these were typically not severe. Recent reports of anaphylaxis epidemiology based on diagnostic coding or attendance for treatment may be biased by differences in health service resource utilization according to the cause and course of the reaction. SUMMARY: Most fatal anaphylactic reactions are unpredictable. The appropriate management after recovery from a severe reaction may be protective against a fatal recurrence. An accurate identification of the cause and effective avoidance is a crucial part of this management, together with effective treatment of asthma for those with food allergy, immunotherapy for sting allergy, the avoidance of drugs that potentiate anaphylaxis, and effective training in self-treatment.

AD Department of Immunology, St Mary’s Hospital, Manchester, UK. richard.pumphrey@cmmc.nhs.uk

PMID 15238794

10

TI Anaphylactic deaths in Auckland, New Zealand: a review of coronial autopsies from 1985 to 2005.

AU Low I; Stables S

SO Pathology. 2006 Aug;38(4):328-32.

AIMS: To determine the frequency of anaphylactic deaths amongst coronial autopsy cases performed in the greater Auckland region from 1985 to 2005, and review the circumstances of death and autopsy findings. METHODS: A computerised search for anaphylactic deaths was performed using the Forensic Pathology Department database at Auckland City Hospital. Postmortem reports and police reports were reviewed to determine the circumstances of death. Details recorded included basic demographic data, medical history, agent responsible for the allergic reaction, and pathologic findings at autopsy. RESULTS: A total of 18 cases of anaphylactic deaths were identified for the study period, including nine males and nine females, age range 33-76 years, mean 51.9 years. There were 10 reactions to drugs or contrast media (4 anaesthetic agents, 3 antibiotic, 2 IV contrast media, 1 streptokinase), four to bee/wasp venom, two to seafood, and two undetermined. Death occurred within 1 hour of onset of anaphylaxis in 12 cases. Findings at autopsy included non-specific pulmonary oedema and congestion (n = 13), laryngeal oedema (n = 5), cerebral hypoxia (n = 4) and cutaneous oedema (n = 1). Serum tryptase levels were measured in 15 cases, and were significantly elevated (>20 microg/L) in eight cases. CONCLUSION: Anaphylactic reaction is an uncommon cause of sudden death. In many cases, no specific macroscopic or microscopic findings were detected at autopsy. In the presence of a typical clinical history, postmortem measurement of serum tryptase levels can be a useful diagnostic aid.

AD Department of Forensic Pathology, Auckland Hospital, New Zealand. irenel@adhb.govt.nz

PMID 16916722

Medline ® Abstracts for References 3,18-20 of ‘Fatal anaphylaxis’

3

TI Lessons for management of anaphylaxis from a study of fatal reactions.

AU Pumphrey RS

SO Clin Exp Allergy 2000 Aug;30(8):1144-50.

BACKGROUND: The unpredictability of anaphylactic reactions and the need for immediate, often improvised treatment will make controlled trials impracticable; other means must therefore be used to determine optimal management. OBJECTIVES: This study aimed to investigate the circumstances leading to fatal anaphylaxis. METHODS: A register was established including all fatal anaphylactic reactions in the UK since 1992 that could be traced from the certified cause of death. Data obtained from other sources suggested that deaths certified as due to anaphylaxis underestimate the true incidence. Details of the previous medical history, the reaction and necropsy were sought for all cases. RESULTS: Approximately half the 20 fatal reactions recorded each year in the UK were iatrogenic, and a quarter each due to food or insect venom. All fatal reactions thought to have been due to food caused difficulty breathing that in 86% led to respiratory arrest; shock was more common in iatrogenic and venom reactions. The median time to respiratory or cardiac arrest was 30 min for foods, 15 min for venom and 5 min for iatrogenic reactions. Twenty-eight per cent of fatal cases were resuscitated but died 3 h-30 days later, mostly from hypoxic brain damage. Adrenaline (epinephrine) was used in treatment of 62% of fatal reactions but before arrest in only 14%. CONCLUSIONS: Immediate recognition of anaphylaxis, early use of adrenaline, inhaled beta agonists and other measures are crucial for successful treatment. Nevertheless, a few reactions will be fatal whatever treatment is given; optimal management of anaphylaxis is therefore avoidance of the cause whenever this is possible. Predictable cross-reactivity between the cause of the fatal reaction and that of previous reactions had been overlooked. Adrenaline overdose caused at least three deaths and must be avoided. Kit for self-treatment had proved unhelpful for a variety of reasons; its success depends on selection of appropriate medication, ease of use and good training.

AD Immunology Unit, Central Manchester Healthcare NHS Trust Hospitals, St Mary’s Hospital, Hathersage Road, Manchester M13 0JH, UK.

PMID 10931122

18

Sheikh, A, Alves, B. Hospital admissions for acute anaphylaxis: time trend study. BMJ 2000; 320:1441.

no abstract available

19

TI Age, sex, geographical and socio-economic variations in admissions for anaphylaxis: analysis of four years of English hospital data.

AU Sheikh A; Alves B

SO Clin Exp Allergy. 2001 Oct;31(10):1571-6.

BACKGROUND: Although the most severe of the allergic disorders, the epidemiology of anaphylaxis remains poorly described. Hospital admissions for anaphylaxis in England more than doubled during the 1990s. OBJECTIVE: To provide baseline data for assessing future trends, and to assess whether there is sufficient regional variation in incidence to allow efficient testing of aetiological hypotheses, we sought to identify any age, sex, geographical and socio-economic variations in hospital inpatient admissions for anaphylaxis. METHODS: We studied all emergency admissions for anaphylaxis to English NHS hospitals between 1991 and 1995. Poisson regression modelling was used to calculate rates of anaphylaxis admission per 100 000 emergency admissions by age, sex, deprivation and by residence in urban/rural, North/South and East/West England. RESULTS: Of the 13.5 million emergency inpatient admissions, 2323 patients had a primary diagnosis of anaphylaxis. Poisson regression analyses showed significant age, gender, geographical and socio-economic variations in emergency admissions for anaphylaxis: adjusted Female rate ratio 1.19 (95% CI 1.09-1.29), South rate ratio 1.35 (95% CI 1.25-1.47), Rural rate ratio 1.35 (95% CI 1.17, 1.59), and Non-deprived rate ratio 1.32 (95% CI 1.19, 1.46). CONCLUSION: This study identifies striking national age, sex, geographical and socio-economic variations in the incidence of inpatient admissions for anaphylaxis in England, affording important opportunities to generate and test aetiological hypotheses. Risk of anaphylaxis admission is considerably increased in females of child-bearing age and those residing in southern, rural, and affluent areas are independent risk factors for anaphylaxis admission.

AD Department of Primary Health Care and General Practice, Division of Primary Care and Population Health Sciences Imperial College School of Medicine, London, UK. aziz.sheikh@ic.ac.uk

PMID 11678857

20

TI Severe food-allergic reactions in children across the UK and Ireland, 1998-2000.

AU Colver AF; Nevantaus H; Macdougall CF; Cant AJ

SO Acta Paediatr. 2005 Jun;94(6):689-95.

AIM: Medical and lay concerns about food allergy are increasing. Whilst food allergy may be becoming more common, fatal reactions to food in childhood are very rare and their rate is not changing. We sought to establish how common severe reactions are. METHODS: Prospective survey, 1998 to 2000, of hospital admissions for food-allergic reactions-conducted primarily through the British Paediatric Surveillance Unit, covering the 13 million children in the United Kingdom and Ireland. RESULTS: 229 cases reported by 176 physicians in 133 departments, yielding a rate of 0.89 hospital admissions per 100,000 children per year. Sixty-five per cent were male, 41% were under 4 y and 60% started at home. Main allergens were peanut (21%), tree nuts (16%), cow’s milk (10%) and egg (7%). Main symptoms were facial swelling (76%), urticaria (69%), respiratory (66%), shock (13%), gastrointestinal (4%). Fifty-eight cases were severe. Three were fatal, six near fatal, and 8 of these 9 had asthma with wheeze being the life-threatening symptom. Three near-fatal cases received excess intravenous epinephrine. None of the non-fatal reactions resulted in mental or physical impairment. Seven of 171 non-severe and 6/58 severe cases might have had a worse outcome if epinephrine auto-injectors had been unavailable. Six of the severe cases might have benefited if auto-injectors had been more widely prescribed. CONCLUSION: In the United Kingdom and Ireland, the incidence of severe reactions is low. The study highlights that: asthma is a strongly significant risk factor for a severe reaction and therefore warrants optimal management; severe wheeze is a prominent feature of severe reactions and warrants optimal management; intravenous epinephrine should be used with great care if needed. Epinephrine auto-injectors do not always prevent death, but our study design and data do not allow a definite statement about whether overall they are beneficial.

AD Sir James Spence Institute, Royal Victoria Infirmary, Northumbria Healthcare NHS Trust and University of Newcastle upon Tyne, Newcastle upon Tyne, UK. allan.colver@ncl.ac.uk

PMID 16188770

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