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Anaphylaxis is a potentially life-threatening, multisystem allergic reaction that can cause airway, breathing, or circulatory compromise. Intramuscular epinephrine is the immediate treatment of all patients. Intravenous epinephrine should be used in patients in shock, either as a bolus or infusion, along with fluid resuscitation. Airway obstruction must be recognized, and early intubation may be necessary. For shock that is refractory to epinephrine, additional vasopressors may be needed. Disposition depends on patient presentation and response to treatment. Mandatory observation periods are not necessary, because biphasic reactions are difficult to predict and may occur outside of typical observation periods., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Background: The use of inconsistent definitions for anaphylaxis outcomes limits our understanding of the natural history and epidemiology of anaphylaxis, hindering clinical practice and research efforts., Objective: Our aim was to develop consensus definitions for clinically relevant anaphylaxis outcomes by utilizing a multidisciplinary group of clinical and research experts in anaphylaxis., Methods: Using Delphi methodology, we developed agenda topics and drafted questions to review during monthly conference calls. Through online surveys, a 19-member panel consisting of experts in allergy and/or immunology and emergency medicine rated their level of agreement with the appropriateness of statements on a scale of 1 to 9. A median value of 1.0 to 3.4 was considered inappropriate, a median value of 3.5 to 6.9 was considered uncertain, and a median value of 7.0 to 9.0 was considered appropriate. A disagreement index was then calculated, with values less than 1.0 categorized as "consensus reached." If consensus was not reached after the initial survey, subsequent surveys incorporating the aggregate de-identified responses from prior surveys were sent to panel members. This process was repeated until consensus was reached or 4 survey rounds had been completed, after which the question was categorized as "no consensus reached.", Results: The panel developed outcome definitions for persistent, refractory, and biphasic anaphylaxis, as well as for persistent and biphasic nonanaphylactic reactions. There was also consensus among panel members regarding the need to develop an anaphylaxis severity grading system., Conclusion: Dissemination and application of these definitions in clinical care and research will help standardize the terminology used to describe anaphylaxis outcomes and serve as the foundation for future research, including research aimed at development of an anaphylaxis severity grading system., (Copyright © 2020 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.)

Food allergies are defined as adverse immune responses to food proteins that result in typical clinical symptoms involving the dermatologic, respiratory, gastrointestinal, cardiovascular, and/or neurologic systems. IgE-mediated food-allergic disease differs from non-IgE-mediated disease because the pathophysiology results from activation of the immune system, causing a T helper 2 response which results in IgE binding to F c ε receptors on effector cells like mast cells and basophils. The activation of these cells causes release of histamine and other preformed mediators, and rapid symptom onset, in contrast with non-IgE-mediated food allergy which is more delayed in onset. The diagnosis of IgE-mediated food allergy requires a history of classic clinical symptoms and evidence of food-specific IgE by either skin-prick or serum-specific IgE testing. Symptoms of IgE-mediated food allergies range from mild to severe. The severity of symptoms is not predicted by the level of specific IgE or skin test wheal size, but the likelihood of symptom onset is directly related. Diagnosis is excluded when a patient can ingest the suspected food without clinical symptoms and may require an in-office oral food challenge if testing for food-specific IgE by serum or skin testing is negative or low. Anaphylaxis is the most severe form of the clinical manifestation of IgE-mediated food allergy, and injectable epinephrine is the first-line treatment. Management of food allergies requires strict avoidance measures, counseling of the family about constant vigilance, and prompt treatment of allergic reactions with emergency medications. Guidelines have changed recently to include early introduction of peanuts at 4-6 months of life. Early introduction is recommended to prevent the development of peanut allergy. Future treatments for IgE-mediated food allergy evaluated in clinical trials include epicutaneous, sublingual, and oral immunotherapy.

We review the history of the classification and coding changes for anaphylaxis and provide current and perspective information in the field. In 2012, an analysis of Brazilian data demonstrated undernotification of anaphylaxis-related deaths because of the difficulties of coding using the International Classification of Diseases, 10th Revision. This work triggered strategic international actions supported by the Joint Allergy Academies and the International Classification of Diseases World Health Organization (WHO) leadership to update the classification of allergic disorders for the International Classification of Diseases, 11th Revision (ICD-11), which resulted in construction of the pioneer "Allergic and hypersensitivity conditions" chapter. The usability of the new framework has been tested by evaluating the same data published in 2012 from the ICD-11 perspective. Coding accuracy was much improved, reaching 95% for definite anaphylaxis. As the results were provided to the WHO Mortality Reference Group, coding rules have been changed, allowing anaphylaxis to be recorded as an underlying cause of death in official mortality statistics. The mandatory use of ICD-11 from January 2022 for documenting cause of death could have 2 immediate consequences: (1) the reported number of anaphylaxis-related deaths might increase because of more appropriate coding and (2) the cross-sectional and longitudinal mortality data generated might ultimately lead to a better understanding of anaphylaxis epidemiology and improved health policies directed at reducing anaphylaxis-related mortality., (Copyright © 2019 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.)

Background: The study of allergic drug reactions has been limited because of challenges in identifying and confirming cases., Objective: To determine the utility of International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes for identifying inpatient allergic drug reactions and to compare findings with previous data in the emergency department., Methods: By reviewing medical records of inpatients with ICD-9-CM codes and E codes suggestive of allergic drug reactions at a large urban academic medical center, we determined codes that yielded the most drug allergy cases and identified culprit drugs., Results: In 2005 and 2010, 3337 and 5282 possible allergic drug reactions during hospitalization were identified and 1367 were reviewed. Allergic drug reactions were found in 409 (30.1%) of the reviewed charts, with 172 (29.7%) in 2005 and 237 (30.5%) in 2010. The codes that identified the highest percentage of true allergic drug reactions were dermatitis due to drug (693.0), allergic urticaria (708), angioneurotic edema (995.1), and anaphylaxis (995.0). Antibiotics were the most common cause (44.4%); however, multiple drug classes were often identified as likely culprit drugs., Conclusion: Specific ICD-9-CM codes can identify patients with allergic drug reactions, with antibiotics accounting for almost half of true reactions. Most patients with codes 693.0, 995.1, 708, and 995.0 had allergic drug reactions, with 693.0 as the highest yield code. An aggregate of multiple specific codes consistently identifies a cohort of patients with confirmed allergic drug reactions., (Copyright © 2019 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.)

Introduction: In May 2008, the Food and Drug Administration launched the Sentinel Initiative, a multi-year program for the establishment of a national electronic monitoring system for medical product safety that led, in 2016, to the launch of the full Sentinel System. Under the Mini-Sentinel pilot, several algorithms for identifying health outcomes of interest, including one for anaphylaxis, were developed and evaluated using data available from the Sentinel common data model., Purpose: To evaluate whether features extracted from unstructured narrative data using natural language processing (NLP) could be used to classify anaphylaxis cases., Methods: Using previously developed methods, we extracted features from unstructured narrative data using NLP and applied rule-based and similarity-based algorithms to identify anaphylaxis among 62 potential cases previously classified by human experts as anaphylaxis (N = 33), not anaphylaxis (N = 27), and unknown (N = 2)., Results: The rule-based and similarity-based approaches demonstrated almost equal performance (recall 100% vs 100%, precision 60.3% vs 57.4%, F-measure: 0.753 vs 0.729). Reasons for misclassification included the inability of the algorithms to make the same clinical judgments as human experts about the timing, severity, or presence of alternative explanations; and the identification of terms consistent with anaphylaxis but present in conditions other than anaphylaxis., Conclusions: Although precision needs to be improved before these algorithms could be used without human review, we demonstrated that applying rule-based and similarity-based algorithms to unstructured narrative information from clinical records can be used for classification of anaphylaxis in the Sentinel System. Further development and assessment of these methods in the Sentinel System are warranted., (© 2018. This article is a U.S. Government work and is in the public domain in the USA.)

Background Pharmacovigilance databases are utilized to identify serious adverse drug events (ADEs). In China, very few studies have evaluated the validity of using pharmacovigilance databases to identify drug-induced anaphylaxis (DIA). Objective We aimed to develop and validate an algorithm to identify DIA using the Beijing Pharmacovigilance Database (BPD). Setting ADEs from the BPD mainly spontaneously reported from 94 hospitals in Beijing, China. Method Using the diagnoses, we developed an algorithm to identify potential DIAs from the BPD between January 2004 and December 2014. A sample of 500 patients was randomly selected for chart abstraction. Two physician adjudicators assessed whether DIA occurred using the published clinical criteria as the gold standard. Main outcome measure Positive predictive values (PPVs) and 95% confidence intervals of the algorithm and algorithm criteria components were calculated. Results 500 patients (53.2% female; the mean age 48.2 years) with potential DIA were selected using the algorithm. 444 were adjudicated as having anaphylaxis by physicians. The PPV of the overall algorithm was 88.8% (95% CI 86.0-91.6%). PPV for the algorithm only using specific diagnoses of "anaphylactic shock", "anaphylactic reaction", and "anaphylactoid reaction [severe]" was 89.6% (95% CI 86.6-92.4%); this partial algorithm identified 387 (87.2%) DIAs. The diagnosis that identified the most DIAs (83.8%) was "anaphylactic shock", with a PPV of 91.6% (95% CI 88.9-94.3%). Conclusion The overall algorithm identified a greater number of DIAs than the algorithm that only used specific diagnoses; however, its PPV was slightly lower. We were able to identify DIAs with the algorithm we developed.

Vasoplegia is the syndrome of pathological low systemic vascular resistance, the dominant clinical feature of which is reduced blood pressure in the presence of a normal or raised cardiac output. The vasoplegic syndrome is encountered in many clinical scenarios, including septic shock, post-cardiac bypass and after surgery, burns and trauma, but despite this, uniform clinical definitions are lacking, which renders translational research in this area challenging. We discuss the role of vasoplegia in these contexts and the criteria that are used to describe it are discussed. Intrinsic processes which may drive vasoplegia, such as nitric oxide, prostanoids, endothelin-1, hydrogen sulphide and reactive oxygen species production, are reviewed and potential for therapeutic intervention explored. Extrinsic drivers, including those mediated by glucocorticoid, catecholamine and vasopressin responsiveness of the blood vessels, are also discussed. The optimum balance between maintaining adequate systemic vascular resistance against the potentially deleterious effects of treatment with catecholamines is as yet unclear, but development of novel vasoactive agents may facilitate greater understanding of the role of the differing pathways in the development of vasoplegia. In turn, this may provide insights into the best way to care for patients with this common, multifactorial condition.

Background: Although currently misclassified in the International Classification of Diseases (ICD) and still not officially listed as a rare disease, anaphylaxis is a well-known clinical emergency. Anaphylaxis is now one of the principal headings in the "Allergic and hypersensitivity conditions" section recently compiled for the forthcoming 11 th Revision of ICD (ICD-11). We here report the building process used for the pioneering "Anaphylaxis" subsection of ICD-11 in which we aimed for transparency as recommended in the ICD-11 revision guidelines., Results: During an online intensive scientific and technical discussions with ICD-11 Topic Advisory Groups and Expert Working Groups, we drafted a total of 35 proposals for the classification of anaphylaxis. From all the 35 proposals, 77% were implemented, 20% remain to be implemented, and the others being partially implemented (1.5%) or rejected (1.5%)., Conclusion: For the first time, anaphylaxis is now properly classified and has attained greater visibility within ICD. In addition to all the benefits expected from the actions we have undertaken in updating the terminology, definitions and classification of allergic and hypersensitivity conditions for ICD-11, we strongly believe that anaphylaxis should be a public health priority and that it should therefore be formally added into the list of rare diseases in order to support awareness and quality clinical management of patients.

Anaphylaxis is defined as a serious allergic or hypersensitivity reaction in the most cases as a result of an IgE-mediated allergic reaction that is rapid in onset and may cause death. Common triggers are foods, insect stings, and medications. The medical treatment includes, epinephrine, glucocorticoids, antihistamines and inhaled bronchodilators, with the aim to prevent progression to life-threatening respiratory and/or cardiovascular symptoms.

Bee and wasp stings can cause allergic reactions. Although the local reactions are more frequent, anaphylaxis due to insect stings can be potentially fatal. Rapid recognition of anaphylaxis is therefore critical and reactions should immediately be treated with i.m. adrenaline. Patients having experienced anaphylaxis should be referred to an allergist for diagnostic evaluation and possible venom-immunotherapy (VIT). The clinical history is essential in diagnosis of venom allergy as the test results are not always reliable. Diagnostic testing with venom components might be beneficial in appropriate patients. The analysis of serum tryptase from the acute episode can be crucial. Mastocytosis is associated in about 8 percent of patients with severe anaphylaxis from insect stings and should be considered in the differential diagnosis. VIT is indicated for patients with a history of anaphylaxis and is effective in preventing future anaphylaxis from Hymenoptera stings.

Anaphylaxis is an acute, severe, systemic hypersensitivity reaction and is potentially fatal. It is sudden and almost always unanticipated, and it involves more than one organ system. Symptom onset varies widely from within seconds to a few hours, but usually occurs within 30 minutes of exposure to the trigger. Early diagnosis and prompt initiation of treatment is important and the diagnosis should be established only when the diagnostic criteria are met. Any delay in the recognition of the initial signs and symptoms can result in a fatal outcome, either because of airway obstruction or circulatory collapse. Adrenaline is the drug of choice and should be immediately administered intramuscularly with suspected reaction.

Purpose: Radiology residencies are increasingly using clinical simulation to teach contrast reaction management. The aim of this study was to evaluate resident documentation of management and transfer of care in severe contrast reactions after a clinical simulation., Methods: After a high-fidelity mannequin simulation of contrast-induced anaphylactic shock, residents (n = 18) were asked to document the event in a progress note and transfer care to a receiving medical team. A total of 22 prospectively determined criteria were selected, and notes were analyzed by a blinded reviewer., Results: Notes contained between 12 and 21 of the prospectively determined 22 criteria (54%-95%). The median number of criteria contained in a note was 16. None of the notes fulfilled all 22 criteria. However, consistent deficiencies were found in documenting prior reaction to contrast (28%) and transfer-of-care criteria (22%-44%)., Conclusions: Although standards for the documentation of advanced cardiovascular life support codes and other emergencies have been devised, no such standards exist for documentation in the management of contrast reactions. The results of this study suggest the need to develop a standardized documentation system for severe contrast-induced reactions. Education regarding transfer of care and documentation should be emphasized during clinical simulation., (Copyright © 2015 American College of Radiology. Published by Elsevier Inc. All rights reserved.)

Aim: Emergency department (ED) visits for food-related acute allergic reactions enable estimation of temporal trends in food allergy prevalence. To use this approach in New Zealand requires an understanding of the proportion of ED visits coded as 'anaphylaxis, unspecified' or 'allergy, unspecified' that are food-related allergic reactions., Method: We reviewed all ED presentations of children, coded as 'anaphylaxis, unspecified' or 'allergy, unspecified', from 1988-2011 to the Auckland City Hospital ED. Charts were reviewed independently by two investigators to determine agreement on categorisation of presentations as being food-related acute allergic reactions. We compared ED presentation rates in different time intervals using rate ratios (RR) and 95% confidence intervals (CI)., Results: Sixty-five (29%) of the 221 ED presentations given a discharge code of 'anaphylaxis, unspecified' or 'allergy, unspecified', were a food-related allergic reaction. Inter-observer agreement was very good (kappa >0.80). The ED presentation rate with food-related allergic reactions in 2004-2011 was 98% higher than in 1988-1995 (RR=1.98, 95%CI 1.10-3.72). By contrast, ED presentation rates for non-food-related allergic reactions did not change over these years., Conclusion: ED presentations for food-related allergic reactions are identifiable from within ED presentations coded as 'anaphylaxis, unspecified' or 'allergy, unspecified'. ED presentations for food-related allergic reactions have increased over time in Auckland.

Anaphylaxis is a potentially life-threatening systemic allergic reaction involving several organ systems. Recognition of the reaction leading to prompt treatment is essential for a good outcome. The lifesaving treatment is intramuscular injection of adrenaline (0.3-0.5 mg for adults and children > 40 kg, 0.3 mg for children 20-40 kg and 0.15 mg for infants < 20 kg). The patient must be placed on the back with elevated lower extremities to improve cerebral and cardiac circulation. High dose oxygen and crystalloid fluid load are needed to improve oxygenation and cardiac output.