Risk factors and treatment of refractory anaphylaxis - a review of case reports

Risk Factors for Refractory Anaphylaxis in the Emergency Department

Background: Anaphylaxis is a serious allergic reaction that has a rapid onset and can result in death. Identifying the factors that trigger anaphylaxis and increase its severity is important for preventing refractory anaphylaxis (RA). In this study, we aimed to determine the factors associated with an increased risk of developing RA. Preventive measures to reduce the frequency and intensity of anaphylactic events are essential to provide the best care for allergic patients. Aggravating factors can trigger or increase the severity of anaphylaxis and therefore need to be recognized and avoided. Methods: We retrospectively analyzed the data of 1378 patients over the age of 18 who were diagnosed with anaphylaxis in our clinic between January 1, 2020, and December 31, 2024. We divided the patients into two groups: anaphylaxis and RA. We evaluated the patients' clinical characteristics in the ED, demographic information, and elicitors that caused anaphylaxis. Results: Of the 1384 anaphylaxis patients included in the study, 46 (3.3%) were diagnosed as RA. We determined that having a history of anaphylaxis is the most important determinant of the increased risk of RA. Having a history of anaphylaxis (OR: 2.87, 95% CI: 1.71-5.72), beta-blockers/ACEI use (OR: 2.47, 95% CI: 1.71-5.42), IV contrast agent (OR: 2.33, 95% CI: 1.64-5.39), and low blood pressure or related symptoms (OR: 2.34, 95% CI: 1.67-5.43) were more frequently associated with severe reactions. Conclusion: We found that having low blood pressure or related symptoms, a known history of anaphylaxis, beta-blockers/ACEI, and IV contrast agent are risk factors for RA. To prevent mortality and morbidity in patients with this risk factor, early interventions such as rapidly repeating epinephrine doses and rapid fluid resuscitation should not be avoided.

Management of Refractory Anaphylaxis: An Overview of Current Guidelines

In this review, we compare different refractory anaphylaxis (RA) management guidelines focusing on cardiovascular involvement and best practice recommendations, discuss postulated pathogenic mechanisms underlining RA and highlight knowledge gaps and research priorities. There is a paucity of data supporting existing management guidelines. Therapeutic recommendations include the need for the timely administration of appropriate doses of aggressive fluid resuscitation and intravenous (IV) adrenaline in RA. The preferred second-line vasopressor (noradrenaline, vasopressin, metaraminol and dopamine) is unknown. Most guidelines recommend IV glucagon for patients on beta-blockers, despite a lack of evidence. The use of methylene blue or extracorporeal life support (ECLS) is also suggested as rescue therapy. Despite recent advances in understanding the pathogenesis of anaphylaxis, the factors that lead to a lack of response to the initial adrenaline and thus RA are unclear. Genetic factors, such as deficiency in platelet activating factor-acetyl hydrolase or hereditary alpha-tryptasaemia, mastocytosis may modulate reaction severity or response to treatment. Further research into the underlying pathophysiology of RA may help define potential new therapeutic approaches and reduce the morbidity and mortality of anaphylaxis.

Anaphylaxis mortality in the perioperative setting: Epidemiology, elicitors, risk factors and knowledge gaps

Perioperative anaphylaxis (PA) is a severe condition that can be fatal, but data on PA mortality are scarce. The aim of this article is to review the epidemiology, elicitors and risk factors for PA mortality and identify knowledge gaps and areas for improvement regarding the management of severe PA. PA affects about 100 cases per million procedures. Mortality is rare, estimated at 3 to 5 cases per million procedures, but the PA mortality rate is higher than for other anaphylaxis aetiologies, at 1.4% to 4.8%. However, the data are incomplete. Published data mention neuromuscular blocking agents and antibiotics, mainly penicillin and cefazolin, as the main causes of fatal PA. Reported risk factors for fatal PA vary in different countries. Most frequently occurring comorbidities are obesity, male gender, cardiovascular diseases and ongoing treatment with beta-blockers. However, there are no clues about how these factors interact and the impact of individual risk factors. The pathophysiology of fatal PA is still not completely known. Genetic factors such as deficiency in PAF-acetyl hydrolase and hereditary alpha-tryptasemia, have been reported as modulators of severe anaphylaxis and possible targets for specific treatments. Our review underlines unmet needs in the field of fatal PA. Although we confirmed the need for timely administration of an adequate dose of adrenaline and the proper infusion of fluids, there is no evidence-based data on the proper dose of intravenous titrated adrenaline and which clinical manifestations would flag the need for fluid therapy. There are no large clinical studies supporting the administration of alternative vasopressors, such as glucagon and methylene blue. Further research on pathophysiological mechanisms of PA and its severity may address these issues and help clinicians to define new therapeutic approaches.

Biologics to treat anaphylaxis

PURPOSE OF REVIEW

The purpose of this literature review was to review the latest use of biologics in the management of anaphylaxis. The methodology was to highlight both the nonbiologic management of anaphylaxis and the biologic management and how they can be used in conjunction with each other.

RECENT FINDINGS

As the phenotypes and endotypes of anaphylaxis are better portrayed, it furthers our understanding of the mechanisms of anaphylaxis. New applications of existing biologics to the prevention of anaphylaxis are described.

SUMMARY

Anaphylaxis is a potentially life-threatening acute hypersensitivity reaction affecting up to 16.8% of the U.S. population. Acute management entails swift identification, removal of the causative agent, and the prevention of cardiovascular collapse, firstly with epinephrine. Adjunctive treatments such as antihistamines work to prevent anaphylaxis from recurring. Biologic management of anaphylaxis involves the use of large-molecule drugs such as monoclonal antibodies. Omalizumab, an IgG1 monoclonal antibody targeting unbound IgE, is the most prevalent and widely studied biologic in the prevention of anaphylaxis. Other monoclonal antibodies in development or approved for other indications, such as ligelizumab, quilizumab, MEDI4212, and dupilumab, may also have potential for preventing anaphylaxis through various mechanisms.

WAO consensus on DEfinition of Food Allergy SEverity (DEFASE)

Background

While several scoring systems for the severity of anaphylactic reactions have been developed, there is a lack of consensus on definition and categorisation of severity of food allergy disease as a whole.

Aim

To develop an international consensus on the severity of food allergy (DEfinition of Food Allergy Severity, DEFASE) scoring system, to be used globally.

Methods Phase 1

We conducted a mixed-method systematic review (SR) of 11 databases for published and unpublished literature on severity of food allergy management and set up a panel of international experts.

Phase 2

Based on our findings in Phase 1, we drafted statements for a two-round modified electronic Delphi (e-Delphi) survey. A purposefully selected multidisciplinary international expert panel on food allergy (n = 60) was identified and sent a structured questionnaire, including a set of statements on different domains of food allergy severity related to symptoms, health-related quality of life, and economic impact. Participants were asked to score their agreement on each statement on a 5-point Likert scale ranging from "strongly agree" to "strongly disagree". Median scores and percentage agreements were calculated. Consensus was defined a priori as being achieved if 70% or more of panel members rated a statement as "strongly agree" to "agree" after the second round. Based on feedback, 2 additional online voting rounds were conducted.

Results

We received responses from 92% of Delphi panel members in round 1 and 85% in round 2. Consensus was achieved on the overall score and in all of the 5 specific key domains as essential components of the DEFASE score.

Conclusions

The DEFASE score is the first comprehensive grading of food allergy severity that considers not only the severity of a single reaction, but the whole disease spectrum. An international consensus has been achieved regarding a scoring system for food allergy disease. It offers an evaluation grid, which may help to rate the severity of food allergy. Phase 3 will involve validating the scoring system in research settings, and implementing it in clinical practice.

Anaphylaxis in older adult patients: a 10-year retrospective experience

Background

Despite the worldwide increase in life expectancy and the elderly population, very little is known about the characteristics of anaphylaxis in older adults.

Methods

A retrospective scan was made of the files of patients who presented at the Allergy Unit of our clinic between October 2011 and October 2021. The study included 971 patients aged ≥18 years who met the criteria for diagnosis of anaphylaxis. The patients were separated into 2 groups of adults (18–64 years) and older adults (≥65 years).

Results

The adult group included 887 (91.3%) patients and the older adult group, 84 (8.7%) patients. Comorbid diseases were seen more frequently in the older adults than in the adult group (p < 0.001). Drugs were seen to be the most common trigger of anaphylaxis in both groups, and this was more common in the older adult group (p = 0.039). Food was a more common trigger of anaphylaxis in the adult group than in the older adult group (p = 0.017). In both groups, the skin was the organ most affected, and was less affected in the older adults than in the adults (p = 0.020). Cardiovascular symptoms were seen significantly more and respiratory symptoms significantly less in the older adult group (p < 0.001, p = 0.002, respectively). Admission to the hospital and the intensive care unit was more frequent in the older adult group and rates of adrenalin administration were higher compared to the adult group (p < 0.001 for all).

Conclusion

Anaphylaxis in the older adults is generally caused by drugs. Older adults were found to have more cardiovascular symptoms and more frequent adrenalin injections, hospitalizations and intensive care unit admissions.

A Clinical Practice Guideline for the Emergency Management of Anaphylaxis (2020)

Background: For anaphylaxis, a life-threatening allergic reaction, the incidence rate was presented to have increased from the beginning of the 21st century. Underdiagnosis and undertreatment of anaphylaxis are public health concerns. Objective: This guideline aimed to provide high-quality and evidence-based recommendations for the emergency management of anaphylaxis. Method: The panel of health professionals from fifteen medical areas selected twenty-five clinical questions and formulated the recommendations with the supervision of four methodologists. We collected evidence by conducting systematic literature retrieval and using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) approach. Results: This guideline made twenty-five recommendations that covered the diagnosis, preparation, emergency treatment, and post-emergency management of anaphylaxis. We recommended the use of a set of adapted diagnostic criteria from the American National Institute of Allergy and Infectious Diseases and the Food Allergy and Anaphylaxis Network (NIAID/FAAN), and developed a severity grading system that classified anaphylaxis into four grades. We recommended epinephrine as the first-line treatment, with specific doses and routes of administration for different severity of anaphylaxis or different conditions. Proper dosage is critical in the administration of epinephrine, and the monitor is important in the IV administration. Though there was only very low or low-quality evidence supported the use of glucocorticoids and H1 antagonists, we still weakly recommended them as second-line medications. We could not make a well-directed recommendation regarding premedication for preventing anaphylaxis since it is difficult to weigh the concerns and potential effects. Conclusion: For the emergency management of anaphylaxis we conclude that: • NIAID/FAAN diagnostic criteria and the four-tier grading system should be used for the diagnosis • Prompt and proper administration of epinephrine is critical.

Clinical reasoning in anaphylactic shock: addressing the challenges faced by anaesthesiologists in real time: A clinical review and management algorithms

Acute hypersensitivity reactions to drugs occur infrequently during anaesthesia and the peri-operative period. When clinical presentation includes the classical triad, erythema, cardiovascular abnormalities and increased airway pressure, the diagnosis is evident and the challenge is to prescribe a therapeutic regimen according to guidelines and to manage refractory signs in a timely manner. In many situations, however, the initial clinical signs are isolated, such as increased airway pressure or arterial hypotension. Rendering a differential diagnosis with causes and mechanisms other than acute hypersensitivity reactions (AHRs) is difficult, delaying treatment with possible worsening of the clinical signs, and even death, in previously healthy individuals. In these difficult diagnostic situations, clinical reasoning is mandatory, and guidelines do not explicitly explain the elements on which clinical reasoning can be built. In this article, based on clinical evidence whenever available, experimental data and pathophysiology, we propose algorithms that have been evaluated by experts. The goal of these algorithms is to provide explicit elements on which the differential diagnosis of AHRs can be made, accelerating the implementation of adequate therapy.

Critical Care Management of the Patient With Anaphylaxis: A Concise Definitive Review

OBJECTIVES

Anaphylaxis is a rapidly progressive life-threatening syndrome manifesting as pruritus, urticaria, angioedema, bronchospasm and shock. The goal of this synthetic review is to provide a practical, updated approach to the evaluation and management of this disorder and associated complications.

DATA SOURCES

A MEDLINE search was conducted with the MeSH of anaphylaxis, anaphylactic reaction, anaphylactic shock, refractory anaphylaxis and subheadings of diagnosis, classification, epidemiology, complications and pharmacology. The level of evidence supporting an intervention was evaluated based on the availability of randomized studies, expert opinion, case studies, reviews, practice parameters and other databases (including Cochrane).

STUDY SELECTION

Selected publications describing anaphylaxis, clinical trials, diagnosis, mechanisms, risk factors and management were retrieved (reviews, guidelines, clinical trials, case series) and their bibliographies were also reviewed to identify relevant publications.

DATA EXTRACTION

Data from the relevant publications were reviewed, summarized and the information synthesized.

DATA SYNTHESIS

This is a synthetic review and the data obtained from a literature review was utilized to describe current trends in the diagnosis and management of the patient with anaphylaxis with a special emphasis on newer evolving concepts of anaphylaxis endotypes and phenotypes, management of refractory anaphylaxis in the ICU setting and review of therapeutic options for the elderly patient, or the complicated patient with severe cardiorespiratory complications. Most of the recommendations come from practice parameters, case studies or expert opinions, with a dearth of randomized trials to support specific interventions.

CONCLUSION

Anaphylaxis is a rapidly progressive life-threatening disorder. The critical care physician needs to be familiar with the diagnosis, differential diagnosis, evaluation, and management of anaphylaxis. Skilled intervention in ICUs may be required for the patient with complicated, severe, or refractory anaphylaxis.

Refractory Anaphylaxis: Data From the European Anaphylaxis Registry

Refractory anaphylaxis (unresponsive to treatment with at least two doses of minimum 300 μg adrenaline) is a rare and often fatal hypersensitivity reaction. Comprehensive data on its definition, prevalence, and risk factors are missing. Using the data from the European Anaphylaxis Registry (11,596 cases in total) we identified refractory anaphylaxis cases (n = 42) and analyzed these in comparison to a control group of severe anaphylaxis cases (n = 4,820). The data show that drugs more frequently elicited refractory anaphylaxis (50% of cases, p < 0.0001) compared to other severe anaphylaxis cases (19.7%). Cases elicited by insects (n = 8) were more often due to bees than wasps in refractory cases (62.5 vs. 19.4%, p = 0.009). The refractory cases occurred mostly in a perioperative setting (45.2 vs. 9.05, p < 0.0001). Intramuscular adrenaline (as a first line therapy) was administered in 16.7% of refractory cases, whereas in 83.3% of cases it was applied intravenously (significantly more often than in severe anaphylaxis cases: 12.3%, p < 0.0001). Second line treatment options (e.g., vasopression with dopamine, methylene blue, glucagon) were not used at all for the treatment of refractory cases. The mortality rate in refractory anaphylaxis was significantly higher (26.2%) than in severe cases (0.353%, p < 0.0001). Refractory anaphylaxis is associated with drug-induced anaphylaxis in particular if allergens are given intravenously. Although physicians frequently use adrenaline in cases of perioperative anaphylaxis, not all patients are responding to treatment. Whether a delay in recognition of anaphylaxis is responsible for the refractory case or whether these cases are due to an overflow with mast cell activating substances—requires further studies. Reasons for the low use of second-line medication (i.e., methylene blue or dopamine) in refractory cases are unknown, but their use might improve the outcome of severe refractory anaphylaxis cases.

Drug-induced anaphylaxis—elicitors, mechanisms and diagnosis

Drugs are one of the major causes of anaphylaxis. For example 2346 cases of drug-induced anaphylaxis were reported to the anaphylaxis register as of March 2019. The most common triggers of drug-induced anaphylaxis were nonsteroidal anti-inflammatory drugs (NSAIDs; n = 902) and antibiotics (n = 721). Drug-induced anaphylaxis can be caused by IgE-dependent (e.g., penicillins) and IgE-independent mechanisms. Recently MRG-PX2 has been identified as a receptor for non-IgE-dependent mechanisms. Drug-induced anaphylaxis results more frequently in lethal reactions and is more commonly associated with cardiovascular symptoms. Also therapy refractory anaphylaxis is more frequently triggered by drugs. For the diagnosis of drug-induced anaphylaxis current national and international guidelines should be followed including provocation tests to avoid future reactions.

Anaphylaxis in Elderly Patients-Data From the European Anaphylaxis Registry

Background: Elicitors and symptoms of anaphylaxis are age dependent. However, little is known about typical features of anaphylaxis in patients aged 65 years or more.

Methods: The data from the Network for Online Registration of Anaphylaxis (NORA) considering patients aged ≥65 (elderly) in comparison to data from adults (18–64 years) regarding elicitors, symptoms, comorbidities, and treatment measures were analyzed.

Results: We identified 1,123 elderly anaphylactic patients. Insect venoms were the most frequent elicitor in this group (p < 0.001), followed by drugs like analgesics and antibiotics. Food allergens elicited less frequently anaphylaxis (p < 0.001). Skin symptoms occurred less frequently in elderly patients (77%, p < 0.001). The clinical symptoms were more severe in the elderly (51% experiencing grade III/IV reactions), in particular when skin symptoms (p < 0.001) were absent. Most strikingly, a loss of consciousness (33%, p < 0.001) and preexisting cardiovascular comorbidity (59%, p < 0.001) were more prevalent in the elderly. Finally, adrenaline was used in 30% of the elderly (vs. 26% in the comparator group, p < 0.001) and hospitalization was more often required (60 vs. 50%, p < 0.001).

Discussion and Conclusion: Anaphylaxis in the elderly is often caused by insect venoms and drugs. These patients suffer more often from cardiovascular symptoms, receive more frequently adrenaline and require more often hospitalization. The data indicate that anaphylaxis in the elderly tends to be more frequently life threatening and patients require intensified medical intervention. The data support the need to recognize anaphylaxis in this patient group, which is prone to be at a higher risk for a fatal outcome.