New trends in anaphylaxis

Anaphylaxis in a Swiss university emergency department: clinical characteristics and supposed triggers

BACKGROUND

Anaphylaxis is the most severe form of acute systemic and potentially life-threatening reactions triggered by mast and basophilic cells. Recent studies show a worldwide incidence between 50 and 112 occurrences per 100,000 person-years. The most identified triggers are food, medications, and insect venoms. We aimed to analyze triggers and clinical symptoms of patients presenting to a Swiss university emergency department for adults.

METHODS

Six-year retrospective analysis (01/2013 to 12/2018) of all patients (> 16 years of age) admitted with moderate or severe anaphylaxis (classification of Ring and Messmer ≥ 2) to the emergency department. Patient and clinical data were extracted from the electronic medical database of the emergency department.

RESULTS

Of the 531 includes patients, 53.3% were female, the median age was 38 [IQR 26-51] years. The most common suspected triggers were medications (31.8%), food (25.6%), and insect stings (17.1%). Organ manifestations varied among the different suspected triggers: for medications, 90.5% of the patients had skin symptoms, followed by respiratory (62.7%), cardiovascular (44.4%) and gastrointestinal symptoms (33.7%); for food, gastrointestinal symptoms (39.7%) were more frequent than cardiovascular symptoms (36.8%) and for insect stings cardiovascular symptoms were apparent in 63.8% of the cases.

CONCLUSIONS

Average annual incidence of moderate to severe anaphylaxis during the 6-year period in subjects > 16 years of age was 10.67 per 100,000 inhabitants. Medications (antibiotics, NSAID and radiocontrast agents) were the most frequently suspected triggers. Anaphylaxis due to insect stings was more frequently than in other studies. Regarding clinical symptoms, gastrointestinal symptoms need to be better considered, especially that initial treatment with epinephrine is not delayed.

Overview of registries for anaphylaxis: a scoping review

OBJECTIVE

This review aimed to describe the scope and operational features of anaphylaxis registries, and to assess their contribution to improving knowledge of anaphylaxis and care of patients who experience anaphylaxis by measuring their research output.

INTRODUCTION

Structured data collection and reporting systems, such as registries, are needed to better understand the burden of anaphylaxis and to protect the growing number of patients with severe allergy. There is a need to characterize current anaphylaxis registries to identify their value in anaphylaxis surveillance, management, and research. Information synthesized in this review will provide knowledge on benefits and gaps in current registries, which may inform the implementation and global standardization of future anaphylaxis reporting systems.

INCLUSION CRITERIA

This scoping review considered literature describing registries worldwide that enroll patients who have experienced anaphylaxis. Published and gray literature sources were included if they described the scope and operational features of anaphylaxis registries.

METHODS

This review followed the JBI methodology for scoping reviews. Embase, MEDLINE, Scopus, and CINAHL were searched for relevant articles. Identified keywords and index terms were adapted for searches of gray literature sources, using Google advanced search functions. Only full-text studies in English were considered for inclusion. Two independent reviewers conducted title and abstract screening and those that did not meet the inclusion criteria were excluded. The full text of potentially relevant articles were retrieved; full-text screening and data extraction were also conducted by two independent reviewers. Any discrepancies were resolved through discussion or with a third reviewer. Tables and a narrative summary were used to describe and compare the scope and features (eg, inclusion criteria, patient demographics, clinical symptoms) of the identified anaphylaxis registries, and to outline their output to assess their contribution to research and clinical practice for anaphylaxis.

RESULTS

A total of 77 full-text publications and eight gray literature sources were used to extract data. The literature search identified 19 anaphylaxis registries, with sites in 28 countries including Europe, the United Kingdom, Canada, the United States, Korea, and Australia. The main purposes of the identified registries were to collect clinical data for research; provide clinical support tools to improve patient care; and operate as allergen surveillance systems to protect the wider community with allergies. Differences in inclusion and health care settings exist, with 11 collecting data on anaphylaxis of any cause, two on food reactions alone, three on fatal anaphylaxis, one on perioperative anaphylaxis, and two on allergic reactions (including anaphylaxis). Five registries enroll cases in allergy centers, five in hospital settings, one in schools, and others target a combination of general practitioners, specialists in emergency departments, and other relevant hospital departments and allergy outpatient clinics. Only three registries operate under a mandatory framework. A total of 57 publications were considered research outputs from registries. All registries except two have published studies from collected data, with the greatest number of articles published from 2019 to the present. Publications mostly addressed questions regarding demographic profile, causes and cofactors, severity, fatal reactions, and gaps in management.

CONCLUSIONS

This review demonstrated that anaphylaxis registries differ in their scope and operation, having been established for different purposes. Importantly, registries have contributed significantly to research, which has highlighted gaps in anaphylaxis management, provoking allergens, and informed targets for prevention for severe and fatal events. Beyond this, registries relay information about anaphylaxis to clinicians and regulatory bodies to improve patient care and protect the community. The ability to link registry data with other health datasets, standardization of data across registries, and incorporation of clinical care indicators to promote quality health care across the health system represent important targets for future systems.

Secondary prevention measures in anaphylaxis patients: Data from the anaphylaxis registry

BACKGROUND

Patients with a history of anaphylaxis are at risk of future anaphylactic reactions. Thus, secondary prevention measures are recommended for these patients to prevent or attenuate the next reaction.

METHODS

Data from the Anaphylaxis Registry were analyzed to identify secondary prevention measures offered to patients who experienced anaphylaxis. Our analysis included 7788 cases from 10 European countries and Brazil.

RESULTS

The secondary prevention measures offered varied across the elicitors. A remarkable discrepancy was observed between prevention measures offered in specialized allergy centers (84% of patients were prescribed adrenaline autoinjectors following EAACI guidelines) and outside the centers: Here, EAACI guideline adherence was only 37%. In the multivariate analysis, the elicitor of the reaction, age of the patient, mastocytosis as comorbidity, severity of the reaction, and reimbursement/availability of the autoinjector influence physician's decision to prescribe one.

CONCLUSIONS

Based on the low implementation of guidelines concerning secondary prevention measures outside of specialized allergy centers, our findings highlight the importance of these specialized centers and the requirement of better education for primary healthcare and emergency physicians.

Bacterial secretion of histamine within the gut influences immune responses within the lung

BACKGROUND

Histamine is an important immunomodulator influencing both the innate and adaptive immune system. Certain host cells express the histidine decarboxylase enzyme (HDC), which is responsible for catalysing the decarboxylation of histidine to histamine. We and others have shown that bacterial strains can also express HDC and secrete histamine; however, the influence of bacterial-derived histamine on the host immune responses distant to the gut is unclear.

METHODS

The Escherichia coli BL21 (E coli BL21) strain was genetically modified to express the Morganella morganii (M morganii)-derived HDC gene (E coli BL21_HTW). E coli BL21 and E coli BL21_HTW were gavaged to ovalbumin (OVA) sensitized and challenged mice to investigate the effect of bacterial-derived histamine on lung inflammatory responses.

RESULTS

Oral administration of E coli BL21_HTW, which is able to secrete histamine, to wild-type mice reduced lung eosinophilia and suppressed ex vivo OVA-stimulated cytokine secretion from lung cells in the OVA respiratory inflammation mouse model. In histamine receptor 2 (H2R)-deficient mice, administration of histamine-secreting bacteria also reduced inflammatory cell numbers in bronchoalveolar lavage (BAL). However, the suppressive effect of bacterial-derived histamine on BAL inflammation was lost in HDC-deficient mice. This loss of activity was associated with increased expression of histamine degrading enzymes and reduced histamine receptor expression.

CONCLUSION

Histamine secretion from bacteria within the gut can have immunological consequences at distant mucosal sites, such as within the lung. These effects are influenced by host histamine receptor expression and the expression of histamine degrading enzymes.

The roadmap for the Allergology specialty and allergy care in Europe and adjacent countries. An EAACI position paper

The high prevalence of allergic diseases warrants for sufficient health care provisions available to patients with allergic diseases. Allergy care should be delivered by well-trained specialists. However, the current status of allergy care is not well documented. For this reason a survey among European and a few non-European countries was launched by the National Allergy Society Committee from the European Academy of Allergy and Clinical Immunology and the Union Européenne des Médecins Spécialistes section and board of Allergology. The survey shows that in the vast majority of countries allergy care services are available. However, a substantial heterogeneity is reported regarding recognition of the full specialty, the number of practicing specialists or subspecialists, and training aspects. Growth but also decline of specialty and subspecialties is reported. In addition, the survey gives insight in strengths, weaknesses, opportunities and threats in this field. It appears that the recognition of the full specialty determines strength as well as weakness. Aging of specialists combined with a decline in the number of trainees form a major threat. Opportunities are seen in creating awareness for allergy, focus on attracting young physicians. The conclusion is that harmonization of allergy services across Europe is needed. Investment in young doctors, creating new opportunities and lobbying for the full specialty is required.

Level of knowledge among pharmacists regarding anaphylaxis and the use of epinephrine autoinjectors

BACKGROUND

Epinephrine autoinjectors for intramuscular administration are the treatment of choice for self-medicating severe allergic reactions. Data from the anaphylaxis registry shows that patients rarely use their epinephrine pens. Pharmacists play a key role as liaison between prescribers and patients.

PATIENTS AND METHODS

Using a standardized questionnaire, the objective of the present study was to assess the level of knowledge among pharmacists regarding anaphylaxis and its treatment. Data derived from 213 pharmacists was included in the study.

RESULTS

Our data reveals that pharmacists consider anaphylaxis to be a disorder that is associated with an impairment in quality of life. The most common triggers of anaphylaxis according to pharmacists (insect venom, foods, and drugs) correspond to those listed in the anaphylaxis registry. Based on the survey, pharmacists readily recognize anaphylactic reactions from case descriptions. However, there are still knowledge deficits with respect to the management of anaphylaxis and current guidelines.

CONCLUSIONS

Our findings suggest that the level of knowledge among pharmacists with regard to anaphylaxis warrants improvement. As this professional group plays a crucial part in the care of patients with allergic disorders, future measures should be aimed at strengthening this role by raising awareness and introducing training modules.