Definition, acronyms, nomenclature, and classification of angioedema (DANCE): AAAAI, ACAAI, ACARE, and APAAACI DANCE consensus.

BACKGROUND: Angioedema (AE) manifests with intermittent, localized, self-limiting swelling of the subcutaneous and/or submucosal tissue. AE is heterogeneous, can be hereditary or acquired, may occur only once or be recurrent, may exhibit wheals or not, and may be due to mast cell mediators, bradykinin, or other mechanisms. Several different taxonomic systems are currently used, making it difficult to compare the results of studies, develop multicenter collaboration, and harmonize AE treatment. OBJECTIVE: We developed a consensus on the definition, acronyms, nomenclature, and classification of AE (DANCE). METHODS: The initiative involved 91 experts from 35 countries and was endorsed by 53 scientific and medical societies, and patient organizations. A consensus was reached by online discussion and voting using the Delphi process over a period of 16 months (June 2021 to November 2022). RESULTS: The DANCE initiative resulted in an international consensus on the definition, classification, and terminology of AE. The new consensus classification features 5 types and endotypes of AE and a harmonized vocabulary of abbreviations/acronyms. CONCLUSION: The DANCE classification complements current clinical guidelines and expert consensus recommendations on the diagnostic assessment and treatment of AE. DANCE does not replace current clinical guidelines, and expert consensus algorithms and should not be misconstrued in a way that affects reimbursement of medicines prescribed by physicians using sound clinical judgment. We anticipate that this new AE taxonomy and nomenclature will harmonize and facilitate AE research and clinical studies, thereby improving patient care.

Differences in the Anaphylactic Response between C3H/HeOuJ and BALB/c Mice.

BACKGROUND: Anaphylaxis is a severe and potentially lethal allergic reaction whose incidence is increasing. Murine models can elucidate the underlying mechanisms and pave the way for appropriate therapeutic options. However, differences in strains and protocols hamper comparisons of data between researchers. We performed a parallel study of clinical and immune responses with 2 strains of mice, BALB/c and C3H/HeOuJ, in an allergen-induced systemic anaphylaxis protocol. Both strains have been widely used in allergy models, although they have not been compared in an intraperitoneal systemic model. METHODS: Groups of 5-week-old female BALB/c and C3H/HeOuJ mice were intraperitoneally sensitized with peanut in the presence of adjuvants. Specific immunoglobulin (sIg) G1, sIgG2a, sIgE, total IgE, histamine release, and specific stimulated splenocyte cytokines, interleukin (IL)-4, IL-5, IL-10, IL-12, IL-13, and interferon (IFN)-γ, were assessed. At week 6, mice were intraperitoneally challenged with peanut. Anaphylaxis was evaluated by recognition of clinical symptoms and changes in body temperature. RESULTS: All peanut-sensitized mice induced sIg and developed anaphylactic symptoms upon challenge. Nonetheless, the C3H/HeOuJ strain demonstrated earlier and persistently higher sIgG1 and sIgG2a production, elevated sIgE, and more severe clinical symptoms and histamine release than the BALB/c strain. In contrast, BALB/c exhibited higher release of IL-4, IL-5, IL-10, IL-13, and IFN-γ. CONCLUSIONS: Both models are suitable for studying anaphylaxis. Consequently, they could be used in research on the pathogenesis and therapy of anaphylaxis. However, according to the type of study performed, differences in the specific clinical, humoral, and cellular responses to antigens have to be considered.

Predictive model to differentiate chronic histaminergic angioedema and chronic spontaneous urticaria with angioedema.

Background: Chronic histaminergic angioedema (CHA) may be classified as a separate acquired angioedema (AE) or as an endotype of chronic spontaneous urticaria (CSU). A recent study suggested them to be independent pathologies. Objective: We carried out an exhaustive analysis between CHA and AE-CSU to explore the possible differentiation between them on the bases of a series of predictors. Methods: An observational, retrospective, cross-sectional, and exploratory study was designed. Fifty-six CHA and 40 AE-CSU patients were included. Data were extracted from the year before and year after time of diagnosis. A predictive model was generated by logistic regression, and its discriminatory power was assessed using the area under the receiver operating characteristic curve. Results: The average frequency of AE attacks per year turned out to be higher in the AE-CSU group than in the CHA group, both before (median [interquartile range] 12 [43] vs 8 [16]) and after (24.3 [51.2] vs 2 [4.25]) diagnosis, respectively. The uvula was more frequently affected in CHA. No other differences were found. However, using 7 clinical characteristics of the patients, a multiple logistic regression model was able to predict, with a specificity of 86.4%, a sensitivity of 92.3%, and an area under the curve of 95.1% (P = .024), that CHA and AE-CSU behaved differently. Conclusion: CHA has similar characteristics to AE-CSU, although they slightly differed in the frequency of attacks and their location. Despite its similarities, a multiple logistic regression model that used clinical and evolutionary characteristics allowed the differentiation of both pathologies and supports the idea that these 2 entities are independent.

Serum Amyloid A as a Potential Biomarker for Disease Activity in Chronic Spontaneous Urticaria.

BACKGROUND: Chronic spontaneous urticaria (CSU) is an inflammatory skin disease with a complex physiopathology. Serum amyloid A (SAA), an acute-phase reactant, has been proposed as a potential biomarker in urticaria but has yet to be studied in a population with CSU or correlated with disease activity as indicated by the Urticaria Activity Score summed over 7 days (UAS7). OBJECTIVE: We sought to determine SAA-1 levels in patients with CSU and correlate them with its activity and control, as well as with clinical features of CSU and other potential blood biomarkers. METHODS: We conducted a retrospective multicenter study of 67 patients with CSU, from whom we obtained demographic and clinical data, UAS7 as an indicator of CSU activity, and blood and serum markers. RESULTS: SAA-1 levels positively correlated with UAS7 (rs = 0.47, P < .001). SAA-1 levels were higher in patients with noncontrolled (UAS7 > 6) CSU than in those with controlled (UAS ≤ 6) CSU (P < .001) and were also higher in patients with concomitant angioedema (P = .003) or delayed pressure urticaria (P = .003). CONCLUSION: We propose SAA-1 as a potential biomarker for activity in CSU. Further studies are required to evaluate its potential role as a biomarker for other CSU outcomes, such as response to treatment.

Hereditary angioedema in Spain: medical care and patient journey.

BACKGROUND: Hereditary angioedema due to C1 inhibitor deficiency (HAE-C1INH) is a genetic rare disease characterized by recurrent, transient and unpredictable episodes of cold, non-pruriginous oedema without associated urticaria. The characteristics of the disease have a considerable impact on the quality of life of patients. The aim of this study was to increase understanding of the patient journey of HAE in Spain. METHODS: A multidisciplinary committee of 16 HAE experts (allergy, immunology, emergency department, hospital pharmacy and nursing) and 3 representatives of the Spanish Hereditary Angioedema Patient Association (AEDAF) who were patients or caregivers participated in the study. A review of the publications on HAE treatment was performed. Semi-structured interviews were performed to HAE experts, patients, or caregivers. Three meetings with the experts, patients and caregivers were held to share, discuss, and validate data obtained from literature and interviews and to build the model. RESULTS: Throughout the project, the patient journey has been drawn up, dividing it into the stages of pre-diagnosis, diagnosis and treatment/follow-up. Some areas for improvement have been identified. Firstly, there is a need to enhance awareness and training on HAE among healthcare professionals, with a particular emphasis on primary care and emergency department personnel. Secondly, efforts should be made to minimize patient referral times to allergy/immunology specialists, ensuring timely access to appropriate care. Thirdly, it is crucial to encourage the study of the relatives of diagnosed patients to early identify potential cases. Fourthly, equitable access to self-administered treatments should be ensured, facilitated by systems that enable medication delivery at home and proper education and training for patients. Equitable access to long-term prophylactic treatment should also be prioritized for all patients in need. To standardize HAE management, the development of consensus guidelines that reduce variability in clinical practice is essential. Lastly, promoting research studies to enhance knowledge of the disease and align its treatment with new developments in the healthcare field should be encouraged. CONCLUSIONS: The knowledge of the patient journey in HAE allowed us to identify improvement areas with the final aim to optimize the disease management.

Hereditary angioedema due to C1 inhibitor deficiency: real-world experience from the Icatibant Outcome Survey in Spain.

BACKGROUND: The Icatibant Outcome Survey (IOS) is an international registry monitoring the use of icatibant, a bradykinin B2 receptor antagonist indicated for the acute treatment of hereditary angioedema (HAE) attacks. Our goal was to assess disease characteristics and icatibant treatment outcomes in patients with HAE due to C1 inhibitor deficiency (HAE type 1 or 2 (HAE-1/2)) from Spain relative to other countries participating in IOS. METHODS: Descriptive retrospective analyses of data are reported from 10 centers in Spain vs 51 centers in 12 other participating countries (July 2009 to January 2019). RESULTS: No meaningful differences were identified between patients in Spain (n = 119) and patients across other countries (n = 907) regarding median age at symptom onset (15.0 vs 12.0 years) or diagnosis (22.3 vs 20.5 years). Overall HAE attack rates (total attacks/total years of follow-up) were 2.66 in Spain and 1.46 across other countries. Patients in Spain reported fewer severe/very severe HAE attacks before treatment (41.0% vs 45.9%; P < 0.0001) and, for icatibant-treated attacks, longer median time to treatment (2.9 vs 1.0 h), time to attack resolution (18.0 vs 5.5 h), and total attack duration (24.6 vs 8.0 h). Use of androgens for long-term prophylaxis was higher in Spain (51.2% vs 26.7%). CONCLUSION: Patients with HAE-1/2 in Spain reported fewer severe/very severe attacks, administered icatibant later, and had longer-lasting attacks than did patients across other countries in IOS. These differences may indicate varying disease management practices (e.g., delayed icatibant treatment) and reporting. Efforts to raise awareness on the benefits of early on-demand treatment may be warranted. TRIAL REGISTRATION: NCT01034969.