Anaphylaxis epidemiology in patients with and patients without asthma: a United Kingdom database review

Patterns of anaphylaxis after diagnostic workup: A follow-up study of 226 patients with suspected anaphylaxis

BACKGROUND

Most published studies on anaphylaxis are retrospective or register based. Data on subsequent diagnostic workup are sparse. We aimed to characterize patients seen with suspected anaphylaxis at the emergency care setting (ECS), after subsequent diagnostic workup at our Allergy Center (AC).

METHODS

Prospective study including patients from the ECS, Odense University Hospital, during May 2013-April 2014. Possible anaphylaxis cases were daily identified based on a broad search profile including history and symptoms in patient records, diagnostic codes and pharmacological treatments. At the AC, all patients were evaluated according to international guidelines.

RESULTS

Among 226 patients with suspected anaphylaxis, the diagnosis was confirmed in 124 (54.9%) after diagnostic workup; 118 of the 124 fulfilled WAO/EAACI criteria of anaphylaxis at the ECS, while six were found among 46 patients with clinical suspicion but not fulfilling the WAO/EAACI criteria at the ECS. The estimated incidence rate of anaphylaxis was 26 cases per 100 000 person-years and the one-year period prevalence was 0.04%. The most common elicitor was drugs (41.1%) followed by venom (27.4%) and food (20.6%). In 13 patients (10.5%), no elicitor could be identified. Mastocytosis was diagnosed in 7.7% of adult patients and was significantly associated with severe anaphylaxis. Atopic diseases were significantly associated only with food-induced anaphylaxis. Cofactors were present in 58.1% and were significantly associated with severe anaphylaxis.

CONCLUSION

A broad search profile in the ECS and subsequent diagnostic workup is important for identification and classification of patients with anaphylaxis. Evaluation of comorbidities and cofactors is important.

The role of human rhinovirus (HRV) species on asthma exacerbation severity in children and adolescents

OBJECTIVE

It is recognized that human rhinovirus (HRV) infection is an important factor in asthma exacerbations requiring hospitalization in children. However, previous studies have disagreed on the differential impact of various HRV species. We sought to assess the impact of HRV species on the severity of asthma exacerbations in children and adolescents. We also examined whether the effect of HRV species on severity was modified by age and gender.

METHODS

Virus strain was determined for 113 children with HRV detectable at the time of admission for asthma exacerbation. Patient characteristics were collected on admission and exacerbation severity was scored using several validated scales.

RESULTS

HRV species by itself was not associated with moderate/severe vs. mild exacerbations. Boys with HRV-C infections were more likely (OR: 3.7, 95% CI: 1.2-13.4) to have a moderate/severe exacerbation than girls with HRV-C (p = 0.04 for interaction term). Higher odds were observed in younger boys (3 years old: OR: 9.1, 95% CI: 1.8-47.1 vs 5 years old: OR: 3.3, 95% CI: 0.9-11.8 vs 7 years old: OR: 1.2, 95% CI: 0.2-6.6). In contrast, children with HRV-C infection and sensitized to pollen during the pollen season were less likely to have moderate/severe exacerbations (p = 0.01 for the interaction term).

CONCLUSION

Acute asthma exacerbations are more likely to be moderate/severe in boys under 5 years of age who had HRV-C infection on admission. The opposite was found in children with sensitization to pollen during pollen season.

Epidemiology of drug-induced anaphylaxis in a tertiary hospital in Korea

BACKGROUND

Epidemiology and risk factors of drug-induced anaphylaxis are difficult to estimate due to lack of confirmative diagnosis and under reporting. Here we report the current state of drug-induced anaphylaxis in Korea based on an in-hospital pharmacovigilance database in a tertiary hospital.

METHODS

This study is a retrospective analysis of drug-induced anaphylaxis, reported to an in-hospital pharmacovigilance center in Seoul National University Hospital from June 2009 to May 2013. Anaphylaxis occurred in patients under 18 years of age or developed by medications administered from outside pharmacies or hospitals were excluded. We assessed causative drug, incidence per use of each drug and risk factors of fatal anaphylactic shock.

RESULTS

A total of 152 in-hospital drug-induced anaphylaxis cases were reported during the study period. The single most frequently reported drug was platinum compound and the incidence of anaphylaxis and anaphylactic shock in platinum compounds users was 2.84 and 1.39 per 1000 patients use. Risk factors of anaphylactic shock among total anaphylaxis cases were identified as older age ≥70 years [Odd's ratio (OR), 5.86; 95% confidence interval (CI), 1.70-20.14]. The use of iodinated contrast media (OR, 6.19; 95% CI, 1.87-20.53) and aminosteroid neuromuscular blocking agent (NMBA) (OR, 12.82; 95% CI, 1.50-109.92) were also a risk factor for the development of anaphylactic shock.

CONCLUSIONS

Platinum compounds are the most commonly reported causative agents of in-hospital drug-induced anaphylaxis. Older age ≥70 years and drugs such as iodinated contrast media and aminosteroid NMBA are related with high risk of anaphylactic shock.

Epidemiology, Mechanisms, and Diagnosis of Drug-Induced Anaphylaxis

Anaphylaxis is an acute, life-threatening, multisystem syndrome resulting from the sudden release of mediators by mast cells and basophils. Although anaphylaxis is often under-communicated and thus underestimated, its incidence appears to have risen over recent decades. Drugs are among the most common triggers in adults, being analgesics and antibiotics the most common causal agents. Anaphylaxis can be caused by immunologic or non-immunologic mechanisms. Immunologic anaphylaxis can be mediated by IgE-dependent or -independent pathways. The former involves activation of Th2 cells and the cross-linking of two or more specific IgE (sIgE) antibodies on the surface of mast cells or basophils. The IgE-independent mechanism can be mediated by IgG, involving the release of platelet-activating factor, and/or complement activation. Non-immunological anaphylaxis can occur through the direct stimulation of mast cell degranulation by some drugs, inducing histamine release and leading to anaphylactic symptoms. Work-up of a suspected drug-induced anaphylaxis should include clinical history; however, this can be unreliable, and skin tests should also be used if available and validated. Drug provocation testing is not recommended due to the risk of inducing a harmful reaction. In vitro testing can help to confirm anaphylaxis by analyzing the release of mediators such as tryptase or histamine by mast cells. When immunologic mechanisms are suspected, serum-sIgE quantification or the use of the basophil activation test can help confirm the culprit drug. In this review, we will discuss multiple aspects of drug-induced anaphylaxis, including epidemiology, mechanisms, and diagnosis.

4-Aminopyridine, A Blocker of Voltage-Dependent K+ Channels, Restores Blood Pressure and Improves Survival in the Wistar Rat Model of Anaphylactic Shock

OBJECTIVES

Anaphylactic shock is associated with severe hypotension. Potassium channel blockers, such as 4-aminopyridine, induce vasoconstriction. The objective of this study was to test the ability of 4-aminopyridine to restore blood pressure and increase survival in anaphylactic shock.

DESIGN

Experimental study.

SETTING

Physiology laboratory.

SUBJECTS

Adult male Wistar rats.

INTERVENTIONS

Rats were sensitized with ovalbumin (1 mg SC), and anaphylactic shock was induced by IV injection of ovalbumin (1 mg). Experimental groups included non-allergic rats (NA) (n = 6); allergic rats (Controls) (n = 6); allergic rats treated with 4-aminopyridine (4-aminopyridine) (1 mg/kg) (n = 6); and allergic rats treated with epinephrine (EPI) (10 µg/kg) (n = 6). Treatments were administered 1 minute after induction of anaphylactic shock.

MEASUREMENTS AND MAIN RESULTS

Mean arterial blood pressure, heart rate, and survival were measured for 60 minutes. Plasma levels of histamine, leukotriene B4, prostaglandin E2, prostaglandin F2, pH, and HCO3 were measured. Mean arterial blood pressure was normal in the NA group; severe hypotension and high mortality were observed in controls; normalization of mean arterial blood pressure, heart rate, and increased survival were observed in 4-aminopyridine and EPI groups. All allergic 4-aminopyridine-treated rats survived after the induction of anaphylactic shock. Histamine level was higher in controls and the 4-aminopyridine group but reduced in the EPI group. Prostaglandin E2 increased in controls and EPI group and decreased in 4-aminopyridine group; prostaglandin F2 increased in controls but decreased in 4-aminopyridine and EPI groups. Leukotriene B4 decreased in 4-aminopyridine and EPI groups. Metabolic acidosis was prevented in the 4-aminopyridine group.

CONCLUSIONS

Our data suggest that voltage-dependent K+ channel inhibition with 4-aminopyridine treatment restores blood pressure and increases survival in the Wistar rat model of anaphylactic shock. 4-aminopyridine or related voltage-dependent K channel blockers could be a useful additional therapeutic approach to treatment of refractory anaphylactic shock.

Food Allergy-Related Risk-Taking and Management Behaviors Among Adolescents and Young Adults

BACKGROUND

Food allergy (FA) affects 8% of children and adolescents in the United States. Nearly 40% of those affected have experienced severe reactions. Fatal food-induced anaphylaxis is most common among adolescents and young adults (AYA); however, FA-related risk behaviors persist in this population and factors associated with these behaviors remain unclear.

OBJECTIVE

To characterize FA-related risk-taking and self-management behaviors of AYA with FA.

METHODS

A cross-sectional survey was administered to 200 AYA with FA. Latent class analysis was used to identify distinct behavioral risk classes and predictors of risk class membership.

RESULTS

Two distinct FA behavioral risk classes were identified, representing less (N = 120) and more (N = 80) risky subpopulations. After adjusting for age, sex, and anaphylaxis history, odds of more risky class membership were significantly reduced for AYA with peanut allergy (odds ratio [OR], 0.27; 95% CI, 0.11-0.65), supportive female friends (OR, 0.27; 95% CI, 0.07-0.99), overprotective mothers (OR, 0.42; 95% CI, 0.18-0.97), teachers who are aware of their FA (OR, 0.39; 95% CI, 0.17-0.91), a history of being bullied (OR, 0.22; 95% CI, 0.09-0.51), and an established 504 education plan (OR, 0.35; 95% CI, 0.15-0.81). AYA also reported numerous positive outcomes of their FA, such as greater responsibility, empathy, and improved diet, which was significantly associated with reduced odds of risky class membership (OR, 0.38; 95% CI, 0.18-0.80).

CONCLUSIONS

Among AYA, increased FA-related risk-taking was associated with clinical, demographic, and social factors, including peanut allergy, greater age, as well as absence of social support and specific school FA policies. These associations may be used to inform future interventions designed to address FA-related risk and management behaviors.

Food Allergy Trends and Epinephrine Autoinjector Presence in Summer Camps

BACKGROUND

Pediatric campers with food allergies are at greater risk for exposure and anaphylaxis. A diagnosis of asthma increases risk for anaphylaxis. Epidemiological investigations of food-allergic children at high risk for allergic reactions requiring intervention in camp settings are lacking.

OBJECTIVE

The objectives of this study were to estimate the prevalence of food allergies among otherwise healthy campers in summer camps throughout the United States and Canada, and to assess asthma comorbidity and determine rates of epinephrine autoinjector prescriptions present in this population.

METHODS

We partnered with CampDoc.com, a web-based camp electronic health record system. Deidentified data were abstracted from 170 camps representing 122,424 campers. Only food allergies with a parental report of symptoms requiring intervention or with a camp prescription for an epinephrine autoinjector were included, whereas gluten, lactose intolerance, and food dyes were excluded. Asthma status and epinephrine presence on the camp medication list were assessed.

RESULTS

Overall, 2.5% of campers (n = 3055) had documented food allergies. Of these campers, 22% had multiple food allergies. Median age was 11 years; 52% were female. Nuts (81%), seafood (17.4%), egg (8.5%), fruit (8.1%), and seeds (7.2%) were the top 5 food allergies reported. Of food-allergic campers, 44.3% had concurrent asthma and 34.7% of those campers were taking multiple asthma medications. Less than half (39.7%) of food-allergic children brought an epinephrine autoinjector to the camp.

CONCLUSIONS

Life-saving epinephrine is not necessarily available for food-allergic children in camp settings. A substantial proportion of food-allergic campers are at higher risk for anaphylaxis based on concurrent asthma status.

Sexual dimorphism in the mast cell transcriptome and the pathophysiological responses to immunological and psychological stress

Background

Biological sex plays a prominent role in the prevalence and severity of a number of important stress-related gastrointestinal and immune-related diseases including IBS and allergy/anaphylaxis. Despite the establishment of sex differences in these diseases, the underlying mechanisms contributing to sex differences remain poorly understood. The objective of this study was to define the role of biological sex on mast cells (MCs), an innate immune cell central to the pathophysiology of many GI and allergic disorders.

Methods

Twelve-week-old C57BL/6 male and female mice were exposed to immunological stress (2 h of IgE-mediated passive systemic anaphylaxis (PSA)) or psychological stress (1 h of restraint stress (RS)) and temperature, clinical scores, serum histamine, and intestinal permeability (for RS) were measured. Primary bone marrow-derived MCs (BMMCs) were harvested from male and female mice and analyzed for MC degranulation, signaling pathways, mediator content, and RNA transcriptome analysis.

Results

Sexually dimorphic responses were observed in both models of PSA and RS and in primary MCs. Compared with male mice, female mice exhibited increased clinical scores, hypothermia, and serum histamine levels in response to PSA and had greater intestinal permeability and serum histamine responses to RS. Primary BMMCs from female mice exhibited increased release of β-hexosaminidase, histamine, tryptase, and TNF-α upon stimulation with IgE/DNP and A23187. Increased mediator release in female BMMCs was not associated with increased upstream phospho-tyrosine signaling pathways or downstream Ca²⁺ mobilization. Instead, increased mediator release in female MCs was associated with markedly increased capacity for synthesis and storage of MC granule-associated immune mediators as determined by MC mediator content and RNA transcriptome analysis.

Conclusions

These results provide a new understanding of sexual dimorphic responses in MCs and have direct implications for stress-related diseases associated with a female predominance and MC hyperactivity including irritable bowel syndrome, allergy, and anaphylaxis.

Electronic supplementary material

The online version of this article (doi:10.1186/s13293-016-0113-7) contains supplementary material, which is available to authorized users.

[Anaphylaxis in children: What pediatricians should know]

Anaphylaxis is a severe potentially life-threatening allergic emergency that has been increasing over the last two decades, especially in young children. Anaphylaxis deaths remain rare, in particular in children, and their frequency is stable during this period. Food is the main anaphylaxis trigger in children, notably to cow's milk, peanuts, and tree nuts. In infants, the recognition of anaphylaxis may be difficult. Vomiting, urticaria, and laryngeal edema are more frequent at this age. Cardiovascular involvement is rare, most often encountered in adolescence. A history of asthma or atopy, allergy to particular foods such as peanuts and tree nuts, and adolescence are some risk factors for anaphylaxis and more severe reactions. First-line treatment is intramuscular adrenaline for all patients experiencing anaphylaxis. There are no absolute contra-indications. Guidelines for the prescription of the adrenaline auto-injector and for establishing a personalized care project in allergic children at school have recently been updated. Recognition of anaphylaxis and treatment should also be improved.

Experimental food allergy to peanut enhances the immune response to house dust mite in the airways of mice

BACKGROUND

Food allergy has been associated with an increased risk for the development of allergic asthma. Asthma is a risk factor for the development of an anaphylactic response to food allergens. An immunological interplay between sensitization to different allergens in different compartments of the body might be involved.

OBJECTIVE

To evaluate the immunological interplay between intragastrical peanut (PE) sensitization and respiratory sensitization to house dust mite (HDM) allergens.

METHODS

BALB/c mice were intragastrically sensitized to peanut or sham-sensitized and challenged systemically to PE. Between sensitization and challenge, mice were intranasally exposed to HDM extract or PBS, as a control. The response to HDM (eosinophil recruitment, cytokine response, HDM-specific immunoglobulins and airway hyper-reactivity) and to PE (cytokine response, mast cells in gut, mMCP-1 in serum and body temperature) was assessed.

RESULTS

A preceding PE sensitization increased HDM-induced production of IL-4, IL-5, IL-13 and IFNγ in lung-draining lymph nodes and total IgE levels in HDM-sensitized mice. However, recruitment of inflammatory cells to the airways or airway hyper-reactivity was not aggravated in PE/HDM double-sensitized mice. Alternatively, HDM-induced airway inflammation did not significantly affect the immune response or the anaphylactic response to a systemic challenge with peanut.

CONCLUSION AND CLINICAL RELEVANCE

Our data show that a preceding peanut sensitization boosted IgE- and HDM-specific Th2 response in the airways in mice. It contributes to the understanding of the underlying immunological mechanism of polysensitization which often occurs in allergic individuals over time.

Cofactors in allergic reactions to food: physical exercise and alcohol are the most important

Introduction

Involvement of cofactors, like physical exercise, alcohol consumption and use of several types of medication, are associated with more severe food allergic symptoms. However, there is limited evidence on how often cofactors play a role in food allergic reactions. The study aimed to get more insight into the frequency of exposure to cofactors and how often cofactors are associated with more severe symptoms in food allergic patients.

Methods

A questionnaire was completed by patients visiting the Allergology outpatient clinic. Patients with food allergy were included. Outcome measures were the frequency of medication use of medication groups that might act as cofactor and the frequency that physical exercise, alcohol consumption and use of analgesics are associated with more severe food allergic symptoms.

Results

Four hundred ninety‐six patients were included in the study. The frequency with which patients used one or more types of medication that might act as cofactors was 7.7%: antacids/acid neutralizing medication (5%), NSAIDs (2%), beta blockers (0.6%), angiotensin‐converting enzyme inhibitors (0.6%), and angiotensin receptor blockers (0.2%). Of all patients, 13% reported more severe symptoms to food after involvement of one or more of the cofactors: physical exercise (10%), alcohol consumption (5%), and use of analgesics (0.6%). Sixty‐five percent did not know if these cofactors caused more severe symptoms; 22% reported that these cofactors had no effect.

Conclusions

Only a small percentage of patients (7.7%) used medication that might aggravate food allergic reactions. Physical exercise and alcohol consumption were the most frequently reported cofactors, but occurring still in only 10% or less.

Particularities of allergy in the Tropics

Allergic diseases are distributed worldwide and their risk factors and triggers vary according to geographical and socioeconomic conditions. Allergies are frequent in the Tropics but aspects of their prevalence, natural history, risk factors, sensitizers and triggers are not well defined and some are expected to be different from those in temperate zone countries. The aim of this review is to investigate if allergic diseases in the Tropics have particularities that deserve special attention for research and clinical practice. Such information will help to form a better understanding of the pathogenesis, diagnosis and management of allergic diseases in the Tropics. As expected, we found particularities in the Tropics that merit further study because they strongly affect the natural history of common allergic diseases; most of them related to climate conditions that favor permanent exposure to mite allergens, helminth infections and stinging insects. In addition, we detected several unmet needs in important areas which should be investigated and solved by collaborative efforts led by the emergent research groups on allergy from tropical countries.

Anaphylaxis in an urban Belgian emergency department: epidemiology and aetiology

OBJECTIVES

Anaphylaxis is an emergency condition of which reliable epidemiological data are lacking. This study focusses on epidemiology and aetiology of anaphylactic reactions in an urban Belgian emergency department (ED).

METHODS

Patient data were collected from 04/2009 to 04/2013.During this period, emergency doctors completed a questionnaire for adult patients (>15 years) with anaphylaxis presenting at the ED. Inclusion criteria were based on the Sampson criteria of anaphylaxis. Data were analysed using a Microsoft Excel database.

RESULTS

Anaphylaxis accounted for 0.04% of all emergency visits in this 4-year period. In both women and men, dyspnoea and urticaria were noted most frequently. 51.7% of cases were possibly elicited by foods, 46.1% by drugs and 3.4% by hymenoptera stings. Women more often reported allergic diseases in their personal history. 55.7% of patients, who had a history of allergy, reported a suspected food-related allergy, 24.6% a drug-related allergy and 8.2% a hymenoptera venom-related allergy. In 76.5% of patients who reported a history of food allergy, food was the presumed elicitor of anaphylaxis. For patients with history of drug allergy, 88.2% had a presumed drug anaphylaxis at the time of presentation at the ED. 81% of cases presented with grade 4 or 5 anaphylaxis. With increasing age, the severity of anaphylaxis increased. Higher tryptase levels correlated with a higher grade of anaphylaxis.

CONCLUSION

In this Belgian urban population, foods and drugs were by far the most common suspected elicitors of anaphylaxis. Personal history of allergic diseases was present in more than half of the cases.

Risk of anaphylaxis after vaccination in children and adults

BACKGROUND

Anaphylaxis is a potentially life-threatening allergic reaction. The risk of anaphylaxis after vaccination has not been well described in adults or with newer vaccines in children.

OBJECTIVE

We sought to estimate the incidence of anaphylaxis after vaccines and describe the demographic and clinical characteristics of confirmed cases of anaphylaxis.

METHODS

Using health care data from the Vaccine Safety Datalink, we determined rates of anaphylaxis after vaccination in children and adults. We first identified all patients with a vaccination record from January 2009 through December 2011 and used diagnostic and procedure codes to identify potential anaphylaxis cases. Medical records of potential cases were reviewed. Confirmed cases met the Brighton Collaboration definition for anaphylaxis and had to be determined to be vaccine triggered. We calculated the incidence of anaphylaxis after all vaccines combined and for selected individual vaccines.

RESULTS

We identified 33 confirmed vaccine-triggered anaphylaxis cases that occurred after 25,173,965 vaccine doses. The rate of anaphylaxis was 1.31 (95% CI, 0.90-1.84) per million vaccine doses. The incidence did not vary significantly by age, and there was a nonsignificant female predominance. Vaccine-specific rates included 1.35 (95% CI, 0.65-2.47) per million doses for inactivated trivalent influenza vaccine (10 cases, 7,434,628 doses given alone) and 1.83 (95% CI, 0.22-6.63) per million doses for inactivated monovalent influenza vaccine (2 cases, 1,090,279 doses given alone). The onset of symptoms among cases was within 30 minutes (8 cases), 30 to less than 120 minutes (8 cases), 2 to less than 4 hours (10 cases), 4 to 8 hours (2 cases), the next day (1 case), and not documented (4 cases).

CONCLUSION

Anaphylaxis after vaccination is rare in all age groups. Despite its rarity, anaphylaxis is a potentially life-threatening medical emergency that vaccine providers need to be prepared to treat.

Epidemiology of anaphylaxis

Knowledge about the epidemiology of anaphylaxis is based on data from various sources: clinical practice, large secondary clinical and administrative databases of primary care or hospitalized patients, and recent surveys with representative samples of the general population. As several similar results are often reported in several publications and populations, such findings are highly like to be robust. One such finding is that the incidence and prevalence of anaphylaxis are higher than previously thought. Publications from the last 5 years reveal an incidence of between 50 and 112 episodes per 100 000 person-years; estimated prevalence is 0.3-5.1% depending on the rigour of the definitions used. Figures are higher in children, especially those aged 0-4 years. Publications from various geographical areas based on clinical and administrative data on hospitalized patients suggest that the frequency of admissions due to anaphylaxis has increased (5-7-fold in the last 10-15 years). Other publications point to a geographic gradient in the incidence of anaphylaxis, with higher frequencies recorded in areas with few hours of sunlight. However, these trends could be the result of factors other than a real change in the incidence of anaphylaxis, such as changes in disease coding and in the care provided. Based on data from the records of voluntary declarations of death by physicians and from large national databases, death from anaphylaxis remains very infrequent and stands at 0.35-1.06 deaths per million people per year, with no increases observed in the last 10-15 years. Although anaphylaxis can be fatal, recurrence of anaphylaxis--especially that associated with atopic diseases and hymenoptera stings--affects 26.5-54% of patients.

Anaphylaxis in the community: a questionnaire survey of members of the UK Anaphylaxis Campaign

Objectives

To examine the circumstances, features and management of anaphylaxis in children and adults.

Design

Self-completed questionnaire.

Participants

The age of participants ranged from 0 to 72 years.

Setting

We analysed data from self-completed questionnaires collected over a 12-year period, i.e. 2001–2013, available to people by phone and, since 2012, for online completion through the Anaphylaxis Campaign.

Main outcome measure

We analysed data from self-completed questionnaires collected over a 12- year period, i.e. 2001-2013, available to people by phone and, since 2012, for online completion through the Anaphylaxis Campaign

Results

In total, 356 questionnaires were submitted, of which 54 did not meet the criteria for anaphylaxis. The remaining 302 anaphylactic reactions originated from 243 individuals; 193 (64%) of these reactions were in children. Approximately half of all reactions occurred at home (n = 148; 49%); 61% (n = 193) of reactions occurred in those reporting a history of asthma, and many (n = 76; 41%) of these individuals had asthma that they classified as being severe. In 57% (n = 173) cases, the respondent reacted to a known allergen. Self-injectable adrenaline (epinephrine) was available in 79% of the cases, and it was only used in 38% of episodes. The usage of self-injected adrenaline was lower in children (30%) than in adults (54%), even though 82% of children had adrenaline available at the time of the reaction compared to 74% of adults.

Conclusions

These data suggest that the majority of anaphylaxis reactions are triggered by exposure to known food allergens and that approximately half of these reactions occur at home. Access to self-injectable adrenaline was sub-optimal and when available it was only used in a minority of cases. Avoiding triggers, access to self-injectable adrenaline and its prompt use in the context of reactions need to be reinforced.

Drug-Induced Anaphylaxis in Latin American Countries

BACKGROUND

Information regarding the clinical features and management of drug-induced anaphylaxis (DIA) in Latin America is lacking.

OBJECTIVE

The objective of this study was to assess implicated medications, demographics, and treatments received for DIA in Latin American patients referred to national specialty centers for evaluation.

METHOD

A database previously used to compile information on drug-induced allergic reactions in 11 Latin American countries was used to identify and characterize patients presenting specifically with a clinical diagnosis of DIA. Information regarding clinical presentation, causative agent(s), diagnostic studies performed, treatment, and contributing factors associated with increased reaction severity was analyzed.

RESULTS

There were 1005 patients evaluated for possible drug hypersensitivity reactions during the study interval, and 264 (26.3%) met criteria for DIA. DIA was more frequent in adults and in elderly females (N = 129 [76.6%] and N = 30 [75%], respectively) compared with children and/or adolescents (N = 21 [42.9%], P < .01). Severe DIA was less frequent with underlying asthma (N = 22 vs 35 [38.6% vs 61.4%], P < .05) or atopy (N = 62 vs 71 [43% vs 59% ], P < .01). Nonsteroidal anti-inflammatory drugs (NSAIDs) (N = 178 [57.8%]), beta-lactam antibiotics (N = 44 [14.3%]), and other antibiotics (N = 16 [5.2%]) were the most frequently implicated drug classes. Anaphylaxis was rated as severe in N = 133 (50.4%) and anaphylactic shock (AS) was present in N = 90 (34.1%). Epinephrine was only used in N = 73 (27.6%) overall, but in N = 70 (77.8%) of patients with AS.

CONCLUSION

In Latin American patients referred for evaluation of DIA, NSAIDs and antibiotics were implicated in approximately 80% of cases. Most of these reactions were treated in the emergency department. Epinephrine was administered in only 27.6% of all cases, although more frequently for anaphylactic shock. Dissemination of anaphylaxis guidelines among emergency department physicians should be encouraged to improve management of DIA.

[Immediate drug hypersensitivity. Epidemiology, clinical features, triggers and management]

Drug hypersensitivity reactions affect more than seven percent of the population and are a concern for patients and doctors alike. In a substantial part of such reactions, IgE-mediated mechanisms have been documented. Clinical manifestations of immediate reactions, which occur directly after drug intake (mostly ≤ 1 h), are acute urticaria, angioedema, dyspnea and other symptoms of anaphylaxis in the skin, gastrointestinal tract, respiratory tract or cardiovascular system. Although normally leading to milder reactions, drugs are also the most frequent elicitors of fatal anaphylaxis. The median time interval between systemic drug application and clinical death is 5 min. The most common elicitors of immediate reactions are analgesics, antibiotics, radiocontrast media and muscle relaxants. The aim of history and experience guided skin tests ± laboratory tests is to document a sensitization, which depends on the eliciting drug and is only successful in less than half of the patients. Else a drug provocation test under controlled conditions is necessary to clarify the diagnosis and to confirm or exclude a drug hypersensitivity reaction. Therapy consists in drug avoidance or in pressing indications in tolerance induction by a "drug desensitization".

Anaphylactic bronchospasm during general anesthesia is not related to asthma

In the general population, a history of asthma (HA) is associated with a higher risk of mortality of anaphylactic shock (AS), but it is unknown whether this association remains valid for intra-operative AS. The goal of this retrospective study was to investigate whether a HA was associated with a higher risk of bronchospasm during intra-operative AS. We analyzed 106 patients (January 2009-December 2012) with intra-operative AS: 57% of them had a confirmed IgE-mediated reaction and 27% had a HA. On logistic regression, the only factor statistically associated with bronchospasm was a neuromuscular blocking drug, with both IgE- or non-IgE-mediated reactions. These results suggest that the mechanisms of bronchospasm in AS may be different from those of asthma and that, in the presence of bronchospasm during anesthesia, AS should be considered to be the most likely cause.

Anaphylaxis to drugs

Drug-induced anaphylaxis is a common cause of anaphylaxis and a leading cause of fatal anaphylaxis. Antibiotics, radiocontrast, and nonsteroidal anti-inflammatory drugs are commonly implicated drugs. Vocal cord dysfunction can mimic anaphylaxis and is often overlooked. β-Lactams are a common cause of anaphylaxis; however, skin testing and drug challenge can usually determine tolerability of other classes of β-lactams. Nonionic contrast agents cause anaphylaxis less frequently than ionic contrast, and immunoglobulin E-mediated mechanisms may have a role in some of these reactions. Skin testing with radiocontrast may have a role in evaluating patients with anaphylaxis to nonionic contrast.

Estrogen increases the severity of anaphylaxis in female mice through enhanced endothelial nitric oxide synthase expression and nitric oxide production

BACKGROUND

Clinical observations suggest that anaphylaxis is more common in adult women compared with adult men, although the mechanistic basis for this sex bias is not well understood.

OBJECTIVES

We sought to document sex-dependent differences in a mouse model of anaphylaxis and explore the role of female sex hormones and the mechanisms responsible.

METHODS

Passive systemic anaphylaxis was induced in female and male mice by using histamine, as well as IgE or IgG receptor aggregation. Anaphylaxis was assessed by monitoring body temperature, release of mast cell mediators and/or hematocrit, and lung weight as a measure of vascular permeability. A combination of ovariectomy, estrogen receptor antagonism, and estrogen administration techniques were used to establish estrogen involvement.

RESULTS

Anaphylactic responses were more pronounced in female than male mice. The enhanced severity of anaphylaxis in female mice was eliminated after pretreatment with an estrogen receptor antagonist or ovariectomy but restored after administration of estradiol in ovariectomized mice, demonstrating that the sex-specific differences are due to the female steroid estradiol. Estrogen did not affect mast cell responsiveness or anaphylaxis onset. Instead, it increased tissue expression of endothelial nitric oxide synthase (eNOS). Blockage of NOS activity with the inhibitor L-NG-nitroarginine methyl ester or genetic eNOS deficiency abolished the sex-related differences.

CONCLUSION

Our study defines a contribution of estrogen through its regulation of eNOS expression and nitric oxide production to vascular hyperpermeability and intensified anaphylactic responses in female mice, providing additional mechanistic insights into risk factors and possible implications for clinical management in the further exploration of human anaphylaxis.

Current immunological and molecular biological perspectives on seafood allergy: a comprehensive review

Seafood is an important component in human diet and nutrition worldwide. However, seafood also constitutes one of the most important groups of foods in the induction of immediate (type I) food hypersensitivity, which significantly impacts the quality of life and healthcare cost. Extensive efforts within the past two decades have revealed the molecular identities and immunological properties of the major fish and shellfish allergens. The major allergen involved in allergy and cross-reactivity among different fish species was identified as parvalbumin while that responsible for shellfish (crustaceans and mollusks) allergy was identified as tropomyosin. The cloning and expression of the recombinant forms of these seafood allergens facilitate the investigation on the detailed mechanisms leading to seafood allergies, mapping of IgE-binding epitopes, and assessment of their allergenicity and stability. Future research focusing on the immunological cross-reactivity and discovery of novel allergens will greatly facilitate the management of seafood allergies and the design of effective and life-long allergen-specific immunotherapies.

Diagnosis and management of food allergies: new and emerging options: a systematic review

It is reported that 6% of children and 3% of adults have food allergies, with studies suggesting increased prevalence worldwide over the last few decades. Despite this, our diagnostic capabilities and techniques for managing patients with food allergies remain limited. We have conducted a systematic review of literature published within the last 5 years on the diagnosis and management of food allergies. While the gold standard for diagnosis remains the double-blind, placebo-controlled food challenge, this assessment is resource intensive and impractical in most clinical situations. In an effort to reduce the need for the double-blind, placebo-controlled food challenge, several risk-stratifying tests are employed, namely skin prick testing, measurement of serum-specific immunoglobulin E levels, component testing, and open food challenges. Management of food allergies typically involves allergen avoidance and carrying an epinephrine autoinjector. Clinical research trials of oral immunotherapy for some foods, including peanut, milk, egg, and peach, are under way. While oral immunotherapy is promising, its readiness for clinical application is controversial. In this review, we assess the latest studies published on the above diagnostic and management modalities, as well as novel strategies in the diagnosis and management of food allergy.

Anaphylaxis: guidelines from the European Academy of Allergy and Clinical Immunology

Anaphylaxis is a clinical emergency, and all healthcare professionals should be familiar with its recognition and acute and ongoing management. These guidelines have been prepared by the European Academy of Allergy and Clinical Immunology (EAACI) Taskforce on Anaphylaxis. They aim to provide evidence-based recommendations for the recognition, risk factor assessment, and the management of patients who are at risk of, are experiencing, or have experienced anaphylaxis. While the primary audience is allergists, these guidelines are also relevant to all other healthcare professionals. The development of these guidelines has been underpinned by two systematic reviews of the literature, both on the epidemiology and on clinical management of anaphylaxis. Anaphylaxis is a potentially life-threatening condition whose clinical diagnosis is based on recognition of a constellation of presenting features. First-line treatment for anaphylaxis is intramuscular adrenaline. Useful second-line interventions may include removing the trigger where possible, calling for help, correct positioning of the patient, high-flow oxygen, intravenous fluids, inhaled short-acting bronchodilators, and nebulized adrenaline. Discharge arrangements should involve an assessment of the risk of further reactions, a management plan with an anaphylaxis emergency action plan, and, where appropriate, prescribing an adrenaline auto-injector. If an adrenaline auto-injector is prescribed, education on when and how to use the device should be provided. Specialist follow-up is essential to investigate possible triggers, to perform a comprehensive risk assessment, and to prevent future episodes by developing personalized risk reduction strategies including, where possible, commencing allergen immunotherapy. Training for the patient and all caregivers is essential. There are still many gaps in the evidence base for anaphylaxis.

International consensus on (ICON) anaphylaxis

ICON: Anaphylaxis provides a unique perspective on the principal evidence-based anaphylaxis guidelines developed and published independently from 2010 through 2014 by four allergy/immunology organizations. These guidelines concur with regard to the clinical features that indicate a likely diagnosis of anaphylaxis -- a life-threatening generalized or systemic allergic or hypersensitivity reaction. They also concur about prompt initial treatment with intramuscular injection of epinephrine (adrenaline) in the mid-outer thigh, positioning the patient supine (semi-reclining if dyspneic or vomiting), calling for help, and when indicated, providing supplemental oxygen, intravenous fluid resuscitation and cardiopulmonary resuscitation, along with concomitant monitoring of vital signs and oxygenation. Additionally, they concur that H1-antihistamines, H2-antihistamines, and glucocorticoids are not initial medications of choice. For self-management of patients at risk of anaphylaxis in community settings, they recommend carrying epinephrine auto-injectors and personalized emergency action plans, as well as follow-up with a physician (ideally an allergy/immunology specialist) to help prevent anaphylaxis recurrences. ICON: Anaphylaxis describes unmet needs in anaphylaxis, noting that although epinephrine in 1 mg/mL ampules is available worldwide, other essentials, including supplemental oxygen, intravenous fluid resuscitation, and epinephrine auto-injectors are not universally available. ICON: Anaphylaxis proposes a comprehensive international research agenda that calls for additional prospective studies of anaphylaxis epidemiology, patient risk factors and co-factors, triggers, clinical criteria for diagnosis, randomized controlled trials of therapeutic interventions, and measures to prevent anaphylaxis recurrences. It also calls for facilitation of global collaborations in anaphylaxis research. IN ADDITION TO CONFIRMING THE ALIGNMENT OF MAJOR ANAPHYLAXIS GUIDELINES, ICON: Anaphylaxis adds value by including summary tables and citing 130 key references. It is published as an information resource about anaphylaxis for worldwide use by healthcare professionals, academics, policy-makers, patients, caregivers, and the public.

Recognition and first-line treatment of anaphylaxis

The International Classification of Diseases (ICD)-9 included a code only for anaphylactic shock. The improved ICD-10 coding defines the different symptoms and types of anaphylaxis and includes coding for anaphylaxis without shock. This new coding is consistent with the efforts of the National Institute of Allergy and Infectious Diseases (NIAID) and the Food Allergy and Anaphylaxis Network (FAAN), who convened a panel to formulate a definition of and the diagnostic criteria for anaphylaxis. Anaphylaxis is a serious reaction that has a rapid onset and may cause death. It is a systemic immunoglobulin E-mediated reaction resulting from the sudden release of multiple mediators from mast cells and basophils. Foods are the most common triggers for anaphylactic reactions, followed by drugs, insect stings, and idiopathic anaphylaxis (anaphylaxis of unknown cause). If the NIAID/FAAN criteria are met and anaphylaxis is diagnosed, epinephrine administration is mandatory. Delays in epinephrine administration have been associated with fatalities. Patients should have ready access to >1 epinephrine autoinjector in the outpatient setting. An individualized emergency action plan should be developed for each patient at risk for anaphylaxis.

The epidemiology of anaphylaxis in Europe: a systematic review

BACKGROUND

Anaphylaxis is an acute, potentially fatal, multi-organ system, allergic reaction caused by the release of chemical mediators from mast cells and basophils. Uncertainty exists around epidemiological measures of incidence and prevalence, risk factors, risk of recurrence, and death due to anaphylaxis. This systematic review aimed to (1) understand and describe the epidemiology of anaphylaxis and (2) describe how these characteristics vary by person, place, and time.

METHODS

Using a highly sensitive search strategy, we identified systematic reviews of epidemiological studies, descriptive and analytical epidemiological investigations, and studies involving analysis of routine data.

RESULTS

Our searches identified a total of 5,843 potentially eligible studies, of which 49 satisfied our inclusion criteria. Of these, three were suitable for pooled estimates of prevalence. The incidence rates for all-cause anaphylaxis ranged from 1.5 to 7.9 per 100,000 person-years. These data indicated that an estimated 0.3% (95% CI 0.1-0.5) of the population experience anaphylaxis at some point in their lives. Food, drugs, stinging insects, and latex were the most commonly identified triggers.

CONCLUSIONS

Anaphylaxis is a common problem, affecting an estimated 1 in 300 of the European population at some time in their lives. Future research needs to focus on better understanding of the trends across Europe and identifying those most likely to experience fatal reactions.

Retrospective study of drug-induced anaphylaxis treated in the emergency department or hospital: patient characteristics, management, and 1-year follow-up

BACKGROUND

Drugs are a common cause of anaphylaxis, which is potentially life threatening.

OBJECTIVE

We sought to describe US patients with an emergency department (ED) visit or hospitalization for drug-induced anaphylaxis (DIA), including postdischarge follow-up care.

METHODS

By using International Classification of Diseases, Ninth Revision codes in the MarketScan Database, we identified all patients with an ED visit and/or hospitalization for DIA between 2002 and 2008 (index date = initial ED visit and/or hospitalization). Inclusion required continuous full insurance coverage ≥1 year in the pre- and postindex period. We examined patient factors during the preindex period, characteristics of the index event, and outcomes during the postindex period.

RESULTS

The cohort included 716 patients with an ED visit and/or hospitalization for DIA (mean age, 48 years; 71% women). Most patients (71%) were managed in the ED, and only 8% of the patients with DIA treated in the ED received epinephrine. For those admitted, patients were hospitalized for a median of 3 days, and 41% spent time in the intensive care unit. Cardiorespiratory failure occurred in 5% of the patients in the ED and 23% of the patients who were hospitalized. The patients with a concomitant allergic condition were more likely to see an allergist/immunologist than those without a concomitant allergic condition, but 82% did not receive any subsequent care with an allergist/immunologist in the 1 year after the ED visit and/or hospitalization for DIA.

CONCLUSION

Drugs are a common, yet under-recognized, cause of anaphylaxis. Only a small number of patients with DIA received epinephrine in the ED or had subsequent care with an allergist/immunologist. These findings are novel and identify areas for improvement in the care of individuals with DIA.

Oxytocin: an unexpected risk for cardiologic and broncho-obstructive effects, and allergic reactions in susceptible delivering women

Oxytocin (Sintocynon) is considered an uncommon cause of severe allergic reactions during delivery. We have recently shown that allergic sensitization to latex might constitute an important predisposing risk factor for anaphylaxis after the first infusion of oxytocin during delivery.Some oxytocin cardiovascular activities such as lowering blood pressure, negative cardiac inotropy and cronotropy, parasympathetic neuromodulation, vasodilatation etc. can induce significant side effects mimicking cardiac anaphylaxis, and constitute an additional differential diagnostic problem in delivering women with suspected or real allergic background. Finally, some ex vivo models have shown that oxytocin, under pro-inflammatory cytokines stimulation, such as those occurring in asthma, may induce contraction of smooth muscle and airway narrowing.This background suggests that allergic sensitization to latex allergens constitutes a significant but underestimated risk factor for triggering severe systemic reactions after the infusion of oxytocin and, consequently, there is a need of particular attention in managing delivering women suffering from latex allergy and bronchial asthma. An accurate anamnestic, clinical and diagnostic evaluation, latex-free anesthesiological setting, use of oxytocin-alternative agents and, if necessary, a drug premedication are likely to reduce the risk of anaphylactic/broncho-obstructive reactions in these women.

Can we predict severe reactions during peanut challenges in children?

BACKGROUND

Limited and contrasting data are available about risk factors for severe reactions during double-blind, placebo-controlled food challenge (DBPCFC). Knowing these risk factors would help to improve safety precautions and choosing the best setting for challenge. We assessed whether we could determine predictors for positive and severe food challenge outcome (FCO) with regular available patient data in children suspected for peanut allergy.

METHODS

A retrospective study in children referred for DBPCFC with peanut was performed during a 3-year period. Reactions during challenge were classified as mild/moderate (Sampson's grade 1-3) and severe (Sampson's grade 4-5). We performed uni- and multivariable logistic regression to determine predictors for positive and severe FCO.

RESULTS

A group of 225 children with a median age of 6.7 (IQR 5.0-9.5) years were studied. In 109 (48%) children, food challenge outcome was positive and 24 (11%) children developed a severe reaction. The level of sIgE for peanut OR 1.14 (1.08-1.20), male gender OR 0.40 (0.20-0.81), having another food allergy OR 0.43 (0.20-0.88), were independently related to positive FCO. No significant differences were found between children with severe and non-severe FCO with respect to age, gender, asthma, sIgE, or previous reaction to peanut.

CONCLUSIONS

Although predictors of positive FCO could be identified, none of the studied risk factors could predict a severe reaction during peanut challenge. When challenging a child sensitized to peanut, clinicians should be prepared and equipped to handle any reaction in all cases.

[Epidemiology of anaphylaxis]

Anaphylaxis is the most severe manifestation of a mast cell dependent hypersensitivity reaction. Recent data on epidemiology indicate that food and drug induced anaphylaxis has increased within the last years. The epidemiological data on anaphylaxis vary throughout the world as the overall incidence and also relevant elicitors depend on different endogenous, but also exogenous factors (e.g. ICD-code, life style, comorbidities). Data from the anaphylaxis registry has shown that venom, drugs and foods are the most frequent elicitors for anaphylaxis within German-speaking countries, while the ranking of the elicitors is age-dependent. Risk factors for anaphylaxis are comorbidities like asthma or mastocytosis or other circumstances, which can increase either the relative risk or the severity. Further risk factors are age, gender and the concomitant intake of drugs like ACE inhibitors or acetylsalicylic acid but also exercise. Data on the clinical epidemiology of anaphylaxis are essential to follow up the most frequent elicitors and risk factors over time and accumulate data about diagnostic and therapeutic procedures in patients suffering from a potential fatal manifestation of an IgE-dependent disease. The anaphylaxis registry within the German-speaking area achieved to provide data of the most frequent elicitors, risk factors and the medical treatment from affected individuals to optimize the management of patients with anaphylaxis.

Concomitant chronic pulmonary diseases and their association with hospital outcomes in patients with anaphylaxis and other allergic conditions: a cohort study

OBJECTIVES

To determine if chronic pulmonary diseases adversely impact selected outcomes in hospitalised patients who have various allergic conditions including anaphylaxis.

DESIGN

A population-based cohort study.

PARTICIPANTS

A statewide hospital inpatient discharge database from Texas, USA, covering the years 2004-2007 was analysed. Patients with anaphylaxis and other allergic conditions were identified using the International Classification of Diseases, Ninth Revision, Clinical Modification codes. Within each group of patients (the overall group with various selected allergic conditions and the subgroup with anaphylaxis), the exposure variables were 11 chronic pulmonary diseases including asthma, chronic obstructive pulmonary disease (COPD) and cystic fibrosis.

PRIMARY OUTCOME MEASURES

Admission to an intensive care unit, a prolonged (>3 days) hospital stay, receipt of mechanical ventilation and death in hospital. Logistic regression was used to calculate adjusted OR and 95% CI for these four outcomes.

RESULTS

30 390 patients with allergic conditions were identified, of whom 2410 had anaphylaxis. The following results pertain to the subcohort of patients with anaphylaxis. Median age was 50 years (range 0-95 years) and 1470 (61%) were female. The hospital mortality was 2.7%. Although asthma was not associated with hospital mortality (OR=1.27, 95% CI 0.55 to 2.90), asthmatics had more than twice the odds of non-asthmatics of receiving mechanical ventilation (OR=2.45, 95% CI 1.81 to 3.33). Chronic bronchitis, COPD, emphysema and interstitial lung diseases (ILDs) were also associated with an increased risk of requiring mechanical ventilation. Chronic bronchitis and COPD were associated with a prolonged length of stay: OR=2.69 (95% CI 1.45 to 4.98) and OR=1.86 (95% CI 1.30 to 2.66), respectively. ILD was the only chronic pulmonary disease associated with an elevated risk of hospital mortality: OR=8.71 (95% CI 1.48 to 51.20).

CONCLUSIONS

In this unique analysis of a large database, we found that asthma, COPD and other chronic pulmonary diseases increased the risk of adverse outcomes among hospitalised patients with anaphylaxis.

Common features of anaphylaxis in children

OBJECTIVE

We aimed to establish the characteristics of anaphylaxis in childhood.

METHODS

Forty-four patients who had experienced anaphylaxis in a period of 10 years (from 1999 to 2009), were included in the study. Parameters analysed were age, gender, concomitant allergic disease, trigger, setting, clinical symptoms, treatment, prognosis and prophylaxis.

RESULTS

The total numbers of anaphylaxis cases were 44 in a ten-year period. The ages of patients ranged from 3 to 14 years (11.50 ± 3.87 years) and the majority were male. 33 of the patients (75%) had a concomitant allergic disease. The trigger was determined in 93.2% of the cases, being most frequent: food (27.3%), and SIT (25%), followed by bee sting, medications and others. Respiratory (95.5%), dermatological (90.9%), cardiovascular (20.5%), neuropsychiatric (25%), and gastrointestinal (11.4%) symptoms were seen most frequently. For anaphylaxis triggered by food, the duration of anaphylactic episode was significantly longer (p<0.05). No biphasic reaction was observed during these attacks. Of our patients, only one developed respiratory failure and cardiac arrest due to SIT, and intensive care support was required.

DISCUSSION

As a trigger for anaphylaxis, the frequency of SIT is so high that it cannot be described by the study group including patients who were followed up in an outpatient allergy clinic.