Perspectives on anaphylaxis epidemiology in the United States with new data and analyses

Active surveillance and clinical analysis of anaphylaxis based on the China Hospital Pharmacovigilance System

Objective: This study aimed to develop active surveillance programs (ASPs) for anaphylaxis using the China Hospital Pharmacovigilance System (CHPS) and analyze the characteristics, allergens, and management strategies for anaphylaxis within a tertiary hospital setting in China. Methods: We retrospectively analyzed the anaphylaxis cases reported to the National Adverse Drug Reaction Monitoring System in our hospital from 2014 to 2021. Characteristic medical orders, progress notes, and diagnoses in these cases were recorded to identify initial anaphylaxis trigger entries. Based on these initial entries, the questionnaire was developed, and the Delphi method was used to establish consensus entries for anaphylaxis triggers. The CHPS was used to program these trigger entries and construct ASPs, which were then tested on the 238,194 discharged patients to evaluate their performance and analyze the related clinical data. Results: Ten anaphylaxis triggers and three ASPs were ultimately identified. The ASPs captured 309 cases, out of which 94 cases were confirmed as anaphylaxis following manual screening. After removing duplicates, we noted 76 patients who experienced anaphylaxis 79 times. The positive rate of triggers and the positive predictive value of the programs were 0.13% and 30.42%, respectively. The incidence of anaphylaxis in our study was 0.03%, and the number of anaphylaxis cases detected by the ASPs was 5.64 times higher than those detected by the spontaneous reporting system. Anaphylaxis was more common among female patients. Antibacterial drugs, antineoplastic drugs, and contrast media were the most prevalent allergens in clinical practice. Anaphylaxis to antineoplastic drugs had the highest incidence (0.6%) when compared with patients admitted during the same period. Our study revealed a significant underuse of epinephrine and overuse of second-line therapy (glucocorticoids and antihistamines) in the management of anaphylaxis. Furthermore, we found the use and dosage of epinephrine to be inappropriate. Conclusion: The CHPS can effectively utilize both structured and unstructured data to construct anaphylaxis ASPs, and this could counteract the under-reporting by the spontaneous reporting system, the primary adverse reaction monitoring method in China. The treatment and management of anaphylaxis are currently inadequate and require improvement to reduce mortality risk.

Improving Methods of Identifying Anaphylaxis for Medical Product Safety Surveillance Using Natural Language Processing and Machine Learning

We sought to determine whether machine learning and natural language processing (NLP) applied to electronic medical records could improve performance of automated health-care claims-based algorithms to identify anaphylaxis events using data on 516 patients with outpatient, emergency department, or inpatient anaphylaxis diagnosis codes during 2015-2019 in 2 integrated health-care institutions in the Northwest United States. We used one site's manually reviewed gold-standard outcomes data for model development and the other's for external validation based on cross-validated area under the receiver operating characteristic curve (AUC), positive predictive value (PPV), and sensitivity. In the development site 154 (64%) of 239 potential events met adjudication criteria for anaphylaxis compared with 180 (65%) of 277 in the validation site. Logistic regression models using only structured claims data achieved a cross-validated AUC of 0.58 (95% CI: 0.54, 0.63). Machine learning improved cross-validated AUC to 0.62 (0.58, 0.66); incorporating NLP-derived covariates further increased cross-validated AUCs to 0.70 (0.66, 0.75) in development and 0.67 (0.63, 0.71) in external validation data. A classification threshold with cross-validated PPV of 79% and cross-validated sensitivity of 66% in development data had cross-validated PPV of 78% and cross-validated sensitivity of 56% in external data. Machine learning and NLP-derived data improved identification of validated anaphylaxis events.

Anaphylaxis among elderly emergency department patients in a large health system in New York

BACKGROUND

Anaphylaxis in the elderly is poorly understood.

OBJECTIVE

To elucidate demographic, clinical, and management characteristics of older adults presenting to emergency departments (EDs) with National Institute of Allergy and Infectious Diseases (NIAID) criteria-confirmed anaphylaxis vs milder, non-anaphylactic acute allergic reactions (AARs).

METHODS

A retrospective analysis of ED patients more than or equal to 65 years was conducted, using anaphylaxis International Classification of Diseases, Ninth Revision (ICD-9) codes or ICD-9-based algorithms incorporating the NIAID diagnostic criteria. Descriptive statistics were generated, and the abovementioned characteristics were compared between cohorts.

RESULTS

Of 164 eligible visits, 71 (43.3%), 90 (54.9%), and 3 (1.8%) cases were identified by ICD-9 codes, the algorithms, or both, respectively. Only half fulfilled NIAID diagnostic criteria. Compared with the non-anaphylactic AAR group, criteria-confirmed anaphylaxis group had lower drug allergy rates (43.9% vs 61.0%, P = .03) but higher food allergy rates (26.8% vs 12.2%, P = .02). For the criteria-confirmed anaphylaxis group, presenting signs and symptoms in descending frequency were mucocutaneous, respiratory, cardiovascular, and gastrointestinal. Criteria-confirmed anaphylaxis group had higher rates of prior anaphylaxis (13.4% vs 2.4%, P = .009), pre-ED (12.2% vs 0.0%, P = .001) or ED (72.0% vs 4.9%, P < .001) epinephrine administration, and allergy referral (17.1% vs 2.4%, P = .002). Tryptase levels were rarely ordered, occurring once in the criteria-confirmed anaphylaxis group and never in the non-anaphylactic AAR group. Despite low mortality (n = 1), 64.6% of the criteria-confirmed anaphylaxis cohort required hospitalization, with 23.2% admitted to intensive care unit.

CONCLUSION

Diagnosis of elderly ED patients with anaphylaxis remains suboptimal. Identifying NIAID criteria-confirmed cases remain challenging, using the existing methods. Management of these patients poorly adheres to current guidelines.

Incidence and trends of limb amputation in first nations and general population in Saskatchewan, 2006-2019

BACKGROUND

There is conflicting evidence whether limb amputation (LA) disproportionately affects indigenous populations. To better understand this disparity, we compared the LA incidence rate between First Nations persons registered under the Indian Act of Canada (RI) and the general population (GP) in Saskatchewan.

METHODS

We used Saskatchewan's retrospective administrative data containing hospital discharge LA cases, demographic characteristics (age and sex), and residents population reported in the database stratified by RI and GP from 2006-2019. The LA cases for each stratified group were first disaggregated into three broad categories: overall LA (all reported LA), primary LA (first reported LA), and subsequent LA (revision or contralateral LA), with each category further split into the level of amputation defined as major amputation (through/above the ankle/wrist joint) and minor amputation (below the ankle/wrist joint). LA rates were calculated using LA cases as the numerator and resident population as the denominator. Joinpoint and negative binomial regressions were performed to explore the trends further.

RESULTS

Overall, there were 1347 RI and 4520 GP LA cases reported in Saskatchewan from 2006-2019. Primary LA made up approximately 64.5% (869) of RI and 74.5% (3369) of GP cases, while subsequent LA constituted 35.5% (478) of RI and 25.5% (1151) of GP cases. The average age-adjusted LA rate was 153.9 ± 17.3 per 100,000 in the RI cohort and 31.1 ± 2.3 per 100,000 in the GP cohort. Overall and primary LA rates for the GP Group declined 0.7% and 1.0%, while subsequent LA increased 0.1%. An increased LA rate for all categories (overall 4.9%, primary 5.1%, and subsequent 4.6%) was identified in the RI group. Overall, minor and major LA increased by 6.2% and 3.3%, respectively, in the RI group compared to a 0.8% rise in minor LA and a 6.3% decline in major LA in the GP group. RI females and males were 1.98-1.66 times higher risk of LA than their GP counterparts likewise, RI aged 0-49 years and 50+ years were 2.04-5.33 times higher risk of LA than their GP cohort. Diabetes mellitus (DM) was the most prevalent amputation predisposing factor in both groups with 81.5% of RI and 54.1% of GP diagnosed with DM. Also, the highest proportion of LA was found in the lowest income quintile for both groups (68.7% for RI and 45.3% for GP).

CONCLUSION

Saskatchewan's indigenous individuals, specifically First Nations persons registered under the Indian Act of Canada, experience LA at a higher rate than the general population. This disparity exists for all variables examined, including overall, primary, and subsequent LA rates, level of amputation, sex, and age. Amplification of the disparities will continue if the rates of change maintain their current trajectories. These results underscore the need for a better understanding of underlying causes to develop a targeted intervention in these groups.

Hymenoptera allergy and anaphylaxis: are warmer temperatures changing the impact?

PURPOSE OF REVIEW

Climate change has brought about many changes in our ecosystem. Prolongation of pollen seasons has been reported, related to earlier frost off in the spring and later onset of frost on in the fall. This review considers recent global evidence that stinging insects are redistributing toward the poles, thereby potentially increasing human exposure and risk of sting events.

RECENT FINDINGS

With changing climate, particularly climate warming, range expansion of insects is occurring in both the Northern and Southern Hemispheres. Likewise, stinging insects, such as Hymenoptera and Lepidoptera, are also expanding range. Though there is scant data on associated increase of insect-related anaphylaxis, increased insect-human interaction is certain.

SUMMARY

It is likely that climate change will continue to alter the distribution and population of Hymenoptera and other insects. As temperatures warm and regions become suitable for nesting and establishment of colonies, many insects will expand their territory. As already reported in Alaska, one would anticipate expansion of range, especially toward the poles, thereby increasing the probability of human encounters and likewise anaphylaxis.

New York State cases of anaphylaxis in elderly patients from 2000 to 2010

BACKGROUND

Limited information is available on the effect of anaphylaxis, a severe, potentially life-threatening allergic reaction, in the elderly population.

OBJECTIVE

To elucidate the frequency of anaphylaxis and the demographic characteristics of elderly patients admitted to New York hospitals from 2000 to 2010.

METHODS

A retrospective analysis of hospitalized patients aged 65 years and older in New York from 2000 to 2010 was conducted using the Statewide Planning and Research Cooperative System, a statewide administrative database. Cases were identified using anaphylaxis International Classification of Diseases, Ninth Revision (ICD-9) codes or an ICD-9-based diagnostic algorithm incorporating the National Institutes of Allergy and Infectious Disease diagnostic criteria. The χ² test was used to measure the association between demographic characteristics and group membership. Regression was used to model group and age as a function of hospital rates.

RESULTS

A total of 3673 hospitalizations were analyzed. Anaphylaxis ICD-9 codes identified 1790 cases (48.7%), the algorithms identified 1701 cases (46.3.%), and 182 cases (5.0%) were identified by both. Hospitalization rates increased significantly during this period (P < .001). Women comprised 61.5% and people of white race comprised 69.8% of the sample. Distribution by age differed by ascertainment method (ICD-9 vs algorithm) among the early-old group (65-74 years of age; 53.8% vs 41.8%) and among the late-old group (≥85 years of age; 11.2% vs 19.3%).

CONCLUSION

Hospitalization rates and anaphylaxis cases increased during the study period among the hospitalized elderly population of New York. Relying on anaphylaxis ICD-9 codes alone missed approximately half of possible cases. The identification and possibly the effect of anaphylaxis among the elderly population may differ, depending on age, race, payer, New York County, and disposition.

Capturing anaphylaxis through medical records: Are ICD and CPT codes sufficient?

OBJECTIVE

The identification of anaphylaxis cases is imperative for optimal clinicalprovider knowledge deficiencies in diagnosis and treatment and the efficacy of reimbursement codes, such as International Classification of Diseases (ICD) and current procedural terminology (CPT) codes, in detecting anaphylaxis.

DATA SOURCES

Pubmed.

STUDY SELECTIONS

Recent and clinically relevant literature on anaphylaxis and provider knowledge, ICD, CPT, Healthcare Common Procedural Coding System (HCPCS), and E-codes were selected and reviewed.

RESULTS

Reimbursement codes are used to detect anaphylaxis in administrative claims databases. Inaccurate recognition of the diagnosis by providers, underreporting, and cause identification are challenges faced by health researchers using reimbursement codes for anaphylaxis case identification. Anaphylactic shock-specific ICD codes were noted to have a positive predictive value (PPV) of 52% to 53% of anaphylaxis events compared with physician chart review, which was improved to 63% to 67.3% when used in conjunction with anaphylaxis symptom-specific ICD, CPT, HCPCS, and E-codes 31, 34, and 35.

CONCLUSION

Education of providers to properly diagnose and treat anaphylaxis requires systematic and educational investments. The ICD codes specific to anaphylactic shock have suboptimal PPV to identify anaphylaxis in administrative claims databases. Use of algorithms incorporating other reimbursement codes improve the PPV, but they are limited by inaccurate diagnoses and underreporting of anaphylaxis. Future ICD-11 reclassification may improve anaphylaxis detection by reimbursement codes.

The Epidemiology of Anaphylaxis

Anaphylaxis is a dramatic expression of systemic allergy. The lifetime prevalence of anaphylaxis is currently estimated at 0.05-2 % in the USA and ~3 % in Europe. Several population-specific studies have noted a rise in the incidence, particularly in the hospitalizations and ER visits due to anaphylaxis. The variable signs and symptoms that constitute the diagnostic criteria for anaphylaxis, the differences in diagnostic algorithms, and the limitations in the current coding systems have made summarizing epidemiologic data and comparing study results challenging. Nevertheless, across all studies, the most common triggers continue to be medications, food, and venom. Various risk factors for more severe reactions generally include older age, history of asthma, and having more comorbid diseases. Interesting seasonal, geographic, and latitude differences have been observed in anaphylaxis prevalence and incidence rates, suggesting a possible role of vitamin D and sun exposure in modifying anaphylaxis risk. While the incidence and prevalence of anaphylaxis appear to be increasing in certain populations, the overall fatality rate remains relatively low.

Association Between Use of Acid-Suppressive Medications and Antibiotics During Infancy and Allergic Diseases in Early Childhood

IMPORTANCE

Allergic diseases are prevalent in childhood. Early exposure to medications that can alter the microbiome, including acid-suppressive medications and antibiotics, may influence the likelihood of allergy.

OBJECTIVE

To determine whether there is an association between the use of acid-suppressive medications or antibiotics in the first 6 months of infancy and development of allergic diseases in early childhood.

DESIGN, SETTING, AND PARTICIPANTS

A retrospective cohort study was conducted in 792 130 children who were Department of Defense TRICARE beneficiaries with a birth medical record in the Military Health System database between October 1, 2001, and September 30, 2013, with continued enrollment from within 35 days of birth until at least age 1 year. Children who had an initial birth stay of greater than 7 days or were diagnosed with any of the outcome allergic conditions within the first 6 months of life were excluded from the study. Data analysis was performed from April 15, 2015, to January 4, 2018.

EXPOSURES

Exposures were defined as having any dispensed prescription for a histamine-2 receptor antagonist (H2RA), proton pump inhibitor (PPI), or antibiotic.

MAIN OUTCOMES AND MEASURES

The main outcome was allergic disease, defined as the presence of food allergy, anaphylaxis, asthma, atopic dermatitis, allergic rhinitis, allergic conjunctivitis, urticaria, contact dermatitis, medication allergy, or other allergy.

RESULTS

Of 792 130 children (395 215 [49.9%] girls) included for analysis, 60 209 (7.6%) were prescribed an H2RA, 13 687 (1.7%) were prescribed a PPI, and 131 708 (16.6%) were prescribed an antibiotic during the first 6 months of life. Data for each child were available for a median of 4.6 years. Adjusted hazard ratios (aHRs) in children prescribed H2RAs and PPIs, respectively, were 2.18 (95% CI, 2.04-2.33) and 2.59 (95% CI, 2.25-3.00) for food allergy, 1.70 (95% CI, 1.60-1.80) and 1.84 (95% CI, 1.56-2.17) for medication allergy, 1.51 (95% CI, 1.38-1.66) and 1.45 (95% CI, 1.22-1.73) for anaphylaxis, 1.50 (95% CI, 1.46-1.54) and 1.44 (95% CI, 1.36-1.52) for allergic rhinitis, and 1.25 (95% CI, 1.21-1.29) and 1.41 (95% CI, 1.31-1.52) for asthma. The aHRs after antibiotic prescription in the first 6 months of life were 2.09 (95% CI, 2.05-2.13) for asthma, 1.75 (95% CI, 1.72-1.78) for allergic rhinitis, 1.51 (95% CI, 1.38-1.66) for anaphylaxis, and 1.42 (95% CI, 1.34-1.50) for allergic conjunctivitis.

CONCLUSIONS AND RELEVANCE

This study found associations between the use of acid-suppressive medications and antibiotics during the first 6 months of infancy and subsequent development of allergic disease. Acid-suppressive medications and antibiotics should be used during infancy only in situations of clear clinical benefit.

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.

Outpatient Emergencies: Anaphylaxis

Anaphylactic fatalities are rare; however, mild reactions can rapidly progress to cardiovascular and respiratory arrest. The clinical course of anaphylaxis can be unpredictable. Prompt and early use of epinephrine should be considered. Most anaphylaxis episodes have an immunologic mechanism involving immunoglobulin E (IgE). Foods are the most common cause in children; medications and insect stings are more common in adults. When the cause is not completely avoidable or cannot be determined, a patient should be supplied with autoinjectable epinephrine and be instructed its use. They should keep the device with them at all times and taught the signs and symptoms of anaphylaxis.

Differences in hospital attendance for anaphylaxis between immigrants and non-immigrants: a cohort study

BACKGROUND

The impact of migration on the risk of anaphylaxis remains unknown. We hypothesized that non-Western immigrants have a lower incidence of anaphylaxis compared to Danish-born. We investigated variations in hospital attendance for anaphylaxis between immigrants and Danish-born including time- and age- trends.

METHODS

A register-based, historical prospective cohort design. Refugees or family reunified immigrants (n = 127 250) who, between January 1, 1994 and December 31, 2010, obtained residency permits in Denmark were included and matched in a 1 : 6 ratio on age and sex with Danish-born individuals (n = 740 600). Personal identification numbers were cross-linked to the Danish National Patient Registry identifying all first-time hospital attendances for anaphylaxis from January 1, 1994 and December 31, 2010. Incidence rate ratios were estimated, stratified for sex and region of birth, adjusting for age using a Cox regression model including the influence of duration of residence and age when residence was obtained.

RESULTS

In total 1053 hospital attendances for anaphylaxis were identified: 89 among non-Western immigrants, 9 among Western immigrants and 955 among Danish-born patients. Both male (RR = 0.65; 95%CI: 0.46;0.90) and female (RR = 0.64; 95%CI: 0.48;0.85) non-Western immigrants had a significantly lower risk ratio of hospital attendance for anaphylaxis compared to Danish-born. Compared to Danish-born, non-Western immigrants living in Denmark during the entire follow-up period also showed a decreased risk (RR = 0.65; 95%CI: 0.34;1.25). Compared to Danish-born, non-Western immigrants who obtained residence permission as children had a decreased risk of hospital attendance for anaphylaxis (RR = 0.48; 95%CI: 0.25;0.91).

CONCLUSION

This Danish register-based study using nationwide data revealed fewer hospital attendances for anaphylaxis among non-Western immigrants compared to Danish-born; however this protection was lost over time.

Variation and Trends in Anaphylaxis Care in United States Children's Hospitals

OBJECTIVES

We sought to determine the extent of variation in treatment of children with anaphylaxis.

METHODS

We identified children 1 month to 18 years of age presenting with a primary diagnosis of anaphylaxis to one of the 35 pediatric hospitals included in the Pediatric Health Information System between January 1, 2009, and September 30, 2013. We evaluated the variation in use of β2 agonists, glucocorticoids, histamine-1 (H1) antagonists, histamine-2 (H2) antagonists, inhaled epinephrine, intravenous fluids, and oxygen. We assessed whether variation exists in the rates of hospitalization and 3-day emergency department (ED) revisits and whether a temporal trend exists in the ED visit rate for anaphylaxis.

RESULTS

Among 10,351 children with anaphylaxis, the hospital-level median use of common anaphylaxis therapies varied for β2 agonists (22%, interquartile range [IQR] = 16%-26%), glucocorticoids (71%, IQR = 65%-76%), H1 blockers (60%, IQR = 57%-65%), H2 blockers (53%, IQR = 36%-64%), inhaled epinephrine (2.2%, IQR = 1.3%-3.5%), intravenous fluids (26%, IQR = 13%-41%), and oxygen (2.6%, IQR = 0.8%-4.1%). Hospitalization rates ranged from 12% to 95%, with a median rate of 41%. Anaphylaxis diagnoses rose from 5.7 to 11.7 patients per 10,000 ED visits between 2009 and 2013 (p < 0.001 for trend).

CONCLUSIONS

There is substantial variability in the use of common therapies and hospitalization rates for children cared for in U.S. children's hospitals. Additionally, ED visits for children with anaphylaxis are increasing at U.S. children's hospitals. These findings highlight the need for research defining optimal care for anaphylaxis.

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.

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.

Management and treatment of anaphylaxis in children: still too low the rate of prescription and administration of intramuscular epinephrine

Despite it being well known that anaphylaxis is a severe life-threatening reaction requiring prompt management and treatment, this entity is still under-recognized and not correctly managed, above all in children. The aim of this study was to analyze the most frequent features of anaphylaxis in a pediatric population (n=65 patients) and to identify factors predicting more severe reactions. Among the 70 recorded episodes, food was the main culprit of anaphylaxis, and patients with a positive history for allergic asthma had more severe episodes (P=0.008). A self-injectable adrenaline was used only in 2 of the 70 episodes and none of the 50 episodes managed in the Emergency Department was treated with intramuscular adrenaline. Only 10/65 patients (15&#x0025;) had a prescription for an auto-injector prior to the first episode of anaphylaxis. The retrospective analysis of the risk factors potentially requiring an epinephrine auto-injector prescription before the first anaphylactic episode, showed that of the 55 patients without prescription, at least 10 (18&#x0025;) should have been provided with a device, according to the most recent guidelines. In conclusion, notwithstanding intramuscular adrenaline being the first-line treatment of anaphylaxis, many episodes are still undertreated and the risk of anaphylaxis is still under-estimated. More efforts should be made to promote the correct management of anaphylaxis among both healthcare-providers and patients.

Anaphylaxis and urticaria

Anaphylaxis and urticaria are common presenting allergic complaints. Affecting up to 2% of the population, anaphylaxis is a serious, life-threatening allergic reaction. Although not life-threatening, urticaria is a rash of transient, erythematous, pruritic wheals that can be bothersome and affects up to 25% of the population. All cases of anaphylaxis warrant thorough clinical evaluation by the allergist-immunologist, although most cases of urticaria are self-limited and do not require specialist referral. This article offers an overview of our current knowledge on the epidemiology, pathogenesis, triggers, diagnosis, and treatment of anaphylaxis and urticaria.

Anaphylaxis: underdiagnosed, underreported, and undertreated

Diagnostic criteria and administrative codes for anaphylaxis have evolved in recent years, partly reflecting the challenges in recognizing anaphylaxis and understanding its symptoms. Before the diagnostic criteria were disseminated by the National Institute of Allergy and Infectious Diseases and the Food Allergy and Anaphylaxis Network, several studies showed that a substantial proportion of anaphylaxis cases presenting to the emergency department (ED) were not recognized as such. Furthermore, epinephrine, the first-line treatment, was used in fewer than half of cases, especially if anaphylaxis was not diagnosed at the time. Although management practices may have improved since that time, anaphylaxis continues to be underrecognized and undertreated in the US. Of particular concern are findings that the majority of patients who visited the ED for an acute allergic reaction or anaphylaxis were not given a prescription for an epinephrine autoinjector, educated about avoiding the offending allergen, or advised to consult with an allergist. Improvements in the recognition and management of anaphylaxis have the potential to reduce the substantial burden that it currently places on the health care system. The articles in this supplement cover a wide range of issues surrounding anaphylaxis and seek to disseminate information helpful to health care professionals in general and primary care providers in particular.

Case fatality and population mortality associated with anaphylaxis in the United States

BACKGROUND

Anaphylaxis is a serious allergic reaction that can cause death; however, the actual risk of death is unclear.

OBJECTIVE

We sought to estimate the case fatality rate among hospitalizations or emergency department (ED) presentations for anaphylaxis and the mortality rate associated with anaphylaxis for the general population.

METHODS

This was a population-based epidemiologic study using 3 national databases: the Nationwide Inpatient Sample (NIS; 1999-2009), the Nationwide Emergency Department Sample (NEDS; 2006-2009), and Multiple Cause of Death Data (MCDD; 1999-2009). Sources for these databases are hospital and ED discharge records and death certificates, respectively.

RESULTS

Case fatality rates were between 0.25% and 0.33% among hospitalizations or ED presentations with anaphylaxis as the principal diagnosis (NIS+NEDS, 2006-2009). These rates represent 63 to 99 deaths per year in the United States, approximately 77% of which occurred in hospitalized patients. The rate of anaphylaxis-related hospitalizations increased from 21.0 to 25.1 per million population between 1999 and 2009 (annual percentage change, 2.23%; 95% CI, 1.52% to 2.94%), contrasting with a decreasing case fatality rate among hospitalizations (annual percentage change, -2.35%; 95% CI, -4.98% to 0.34%). Overall mortality rates ranged from 0.63 to 0.76 per million population (186-225 deaths per year, MCDD) and appeared stable in the last decade (annual percentage change, -0.31%; 95% CI, -1.54% to 0.93%).

CONCLUSION

From 2006 to 2009, the overwhelming majority of hospitalizations or ED presentations for anaphylaxis did not result in death, with an average case fatality rate of 0.3%. Anaphylaxis-related hospitalizations increased steadily in the last decade (1999-2009), but this increase was offset by the decreasing case fatality rate among those hospitalized; both inpatient and overall mortality rates associated with anaphylaxis appeared stable and were well under 1 per million population. Although anaphylactic reactions are potentially life-threatening, the probability of dying is actually very low. With the prevalence of anaphylaxis on the increase, practitioners need to stay vigilant and follow the treatment guidelines to further reduce anaphylaxis-related deaths.

Recognition and treatment of anaphylaxis in the school setting: the essential role of the school nurse

Since anaphylaxis is unpredictable, rapid in onset, and potentially life threatening, it is critical for school staff to recognize and respond to its symptoms quickly. The symptoms of anaphylaxis can be challenging to differentiate, particularly in school-age children who may have trouble explaining what they are experiencing. School staff must understand the distinctive ways in which children describe and manifest anaphylactic symptoms, and the school nurse has a key leadership role in providing this training. The school nurse should create and coordinate individualized emergency care/action plans for students with known allergies, as well as a comprehensive care plan for all students, to ensure a safe environment and a rapid response to any life-threatening allergic reaction. This should include having epinephrine stocked and readily accessible so that it can be given promptly in the case of an anaphylactic emergency.

Food allergy knowledge of parents - is ignorance bliss?

BACKGROUND

Food allergic children are at least partially dependent on their parents to care for their food allergy. In addition, parents are often responsible for the education of others regarding food allergy, including the family, school, neighbors, and friends. The aim of this study was to investigate food allergy knowledge, attitudes, and beliefs of parents with food allergic children in the Netherlands. In addition, a cross-cultural comparison was made between parents from the USA and parents from the Netherlands.

METHODS

The original Chicago Food Allergy Research Survey for Parents of Children with Food Allergy (CFARS-PRNT) was translated into Dutch. Parents of children with at least one doctor-diagnosed food allergy were included. Knowledge scores and attitude/beliefs scores were determined and compared with the data from 2945 parents from the USA. Predictors of overall knowledge scores were investigated.

RESULTS

Dutch parents of children completed the translated CFARS-PRNT (n = 299). The mean overall knowledge score in the Netherlands was 9.9 after adjusting for guessing, compared with 12.7 in the USA (p < 0.001). Attitudes and beliefs regarding food allergy among parents from the Netherlands were generally more optimistic. The overall knowledge scores could be predicted by country of origin, educational degree, being member of a patient organization, visiting an allergist, and a history of anaphylaxis.

CONCLUSIONS

Food allergy knowledge among parents of food allergic children from the Netherlands is suboptimal when compared with their counterparts from the USA, although these parents tend to be more optimistic toward food allergy than parents from the USA.

Latitude, sunlight, vitamin D, and childhood food allergy/anaphylaxis

Vitamin D is widely known for its role in bone metabolism, but this sterol hormone also has important immunomodulatory properties. Vitamin D is produced by the conversion of D3 in the skin following UVB exposure, or after ingestion of D2 or D3. At the extremes of latitude, there is insufficient UVB intensity in the autumn and winter months for adequate synthesis of vitamin D to occur. Growing evidence implicates vitamin D deficiency in early life in the pathogenesis of nonskeletal disorders (e. g., type 1 diabetes and multiple sclerosis) and, more recently, atopic disorders. Several studies have reported higher rates of food allergy/anaphylaxis or proxy measures at higher absolute latitudes. Although causality remains to be determined, these studies suggest a possible role for sunlight and/or vitamin D in the pathogenesis of food allergy/anaphylaxis.

Anaphylaxis in Latin American children and adolescents: the Online Latin American Survey on Anaphylaxis (OLASA)

OBJECTIVES

To identify the main clinical manifestations, triggers, and treatment of severe allergic reactions (SAR) in children and adolescents (n=191, up to 18 years of age) seen by allergologists and registered in the Online Latin American Survey of Anaphylaxis (OLASA).

RESULTS

53.0% of the patients were males and the aetiological agent was identified in 85.5% of them as follows: foods (36.1%), drugs (27.7%), and insect stings (26.2%). The most common symptoms during an acute episode were cutaneous (94.2%), and respiratory (78.5%). Most patients were treated in emergency setting, yet only 34.6% received parenteral epinephrine and 14.3% had to be hospitalised.

CONCLUSION

Cutaneous symptoms ranked the order of clinical presentation of SAR. Food was the main triggering agent in the younger cases and insect sting and drugs in the adolescents. Treatment provided for SAR was not appropriate. It is necessary to improve educational programmes in order to enhance the knowledge on this potentially fatal emergency.

Neonatal vitamin D status and childhood peanut allergy: a pilot study

BACKGROUND

Although a number of factors have been proposed to explain the increase in food allergy during the last decade, the possibility that vitamin D status may play a pathogenic role has received recent attention.

OBJECTIVE

To determine whether lower levels of neonatal 25-hydroxyvitamin D (25[OH]D) would be observed in children with peanut allergy compared with in population controls.

METHODS

The concentration of 25(OH)D was measured from neonatal dried blood samples by liquid chromatography tandem mass spectrometry. Levels were compared between children with IgE-mediated peanut allergy younger than 72 months assessed during 2008-2011 in a specialist referral clinic in the Australian Capital Territory and population births matched by sex, birth date, and birth location. Odds ratios were calculated for the matched pairs across quintiles of 25(OH)D.

RESULTS

Neonatal 25(OH)D levels ranged from 8 to 180 nmol/L (median, 66 nmol/L; interquartile range, 46-93 nmol/L); only 4 children (3%) had levels less than 25 nmol/L, and 24 (20.9%) had levels greater than 100 nmol/L. No significant association was found between socioeconomic or clinical factors and 25(OH)D levels. Compared with the reference group (50-74.9 nmol/L), levels of 75 to 99.9 nmol/L were associated with lower risk of peanut allergy (P = .02). No further reduction was found at levels of 100 nmol/L or higher, and the risk of peanut allergy at levels less than 50 nmol/L was not significantly different from the reference group.

CONCLUSION

The relationship between neonatal 25(OH)D level and childhood peanut allergy was nonlinear, with slightly higher levels (75-99.9 nmol/L) associated with lower risk than those in the reference group (50-74.9 nmol/L). Vitamin D status may be one of many potential factors contributing to childhood peanut allergy pathogenesis.

Epinephrine auto-injector pandemic

Epinephrine is crucial in the treatment of anaphylaxis. As anaphylaxis frequently occurs in nonmedical settings, use of an epinephrine auto-injector is vital for prompt management. This article provides an overview of the increasing number of epinephrine auto-injector prescriptions and the underlying causes and contributing factors to these rising prescriptions. It also reviews the current indications for prescription of an epinephrine auto-injector, proper use of epinephrine auto-injectors, and the management of unintentional epinephrine injections.

Undernotification of anaphylaxis deaths in Brazil due to difficult coding under the ICD-10

BACKGROUND

Undernotification is well recognized as a key challenge to the study of anaphylaxis mortality, but it is seldom mentioned that one of its reasons is the difficult coding of the condition under the tenth revision of the international classification of diseases (ICD-10), given that there are no anaphylaxis-specific ICD-10, which are considered valid for coding underlying causes-of-death, and that official mortality statistics consider exclusively the underlying and disregard the contributing causes-of-death data recorded on death certificates. Brazilian mortality data were used as a case study to call attention to the inadequacy of the ICD-10 for the measurement of anaphylaxis deaths.

METHODS

Underlying and contributing causes-of-death data were used to estimate the rates of anaphylaxis deaths in the country over the years 2008-2010.

RESULTS

Of 498 anaphylaxis deaths were found, of which 75% were classified as 'definite' and 25% as 'possible anaphylaxis deaths'. The average national rate for these years was 0.87 per million per year. None of these deaths would have been found had we exclusively considered information from the underlying cause-of-death field.

CONCLUSION/RECOMMENDATIONS

The study of anaphylaxis mortality using secondary data requires the use of information derived from the underlying as well as from the contributing causes-of-death fields. Coding definitions should be standardized with a view of enabling trend analyses and international comparisons. The ICD-11 revision is a unique opportunity to improve the coding system so as to facilitate epidemiological studies of anaphylaxis mortality. Educational interventions targeted at improving the quality of death certificate completion are urgently needed.

A population-based epidemiologic study of emergency department visits for anaphylaxis in Florida

BACKGROUND

Previous population-based analyses of emergency department (ED) visits for anaphylaxis have been limited to small populations in limited geographic areas and focused on children or have included patients who had allergic conditions other than anaphylaxis.

OBJECTIVE

We sought to describe the epidemiology and risk factors among patients with anaphylaxis presenting to Florida EDs.

METHODS

Two thousand seven hundred fifty-one patients with anaphylaxis were identified for 2005-2006 within ED records by using the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM), and a validated ICD-9-CM-based algorithm. Age- and sex-specific rates were calculated. Regression analyses were used to determine relative risks for anaphylaxis caused by various triggers (food, venom, and medication) and risk factors (age, sex, race, and ethnicity).

RESULTS

The highest observed rates were among the youngest male subjects (8.2/100,000 Floridians aged 0-4 years) and among adult female subjects (15-54 years) grouped in 10-year age categories (9.9-10.9/100,000 Floridians). Male and black subjects were 20% and 25%, respectively, more likely to have a food trigger than female and white subjects. White, male, and older subjects were more likely to have an anaphylaxis-related ED visit caused by insect stings. Venom-induced anaphylaxis was more likely in August through October. Children were less likely than those older than 70 years (referent) to have medication-induced anaphylaxis (P < .03).

CONCLUSION

This is the only ED-based population study in a US lower-latitude state. The overall rate is considerably lower than other US ED-based population studies. The rates of anaphylaxis by age group differed by sex. Male and black subjects were more likely to have a food trigger.