Hereditary Angioedema with Normal C1 Inhibitor: an Updated International Consensus Paper on Diagnosis, Pathophysiology, and Treatment

Hereditary angioedema (HAE) has been recognized for almost 150 years. The newest form of HAE, where C1 inhibitor levels are normal (HAE-nC1INH), was first described in 2000. Over the last two decades, new types of apparent non-mast cell-mediated angioedema with normal quantity and activity of C1INH have been described, in some cases with proven genetic pathogenic variants that co-segregate with angioedema expression within families. Like HAE due to C1INH deficiency, HAE-nC1INH patients are at risk of serious morbidity and mortality. Therefore, proactive management and treatment of HAE-nC1INH patients after an expert physician diagnosis is critically important. The underlying pathophysiology responsible for the angioedema has also been clarified in some of the HAE-nC1INH types. While several clinical guidelines and practice parameters including HAE-nC1INH have been published, we have made substantial progress in our understanding encompassing diagnostic criteria, pathophysiology, and treatment outcomes. HAE International (HAEi) and the US HAE Association (HAEA) convened a symposium of global HAE-nC1INH experts to synthesize our current knowledge in the area. Given the paucity of high-level evidence in HAE-nC1INH, all recommendations are based on expert opinion. This review and expert opinion on the best practice approach to diagnosing and treating HAE-nC1INH will support physicians to better manage patients with HAE-nC1INH.

Epidemiology, economic, and humanistic burden of hereditary angioedema: a systematic review

BACKGROUND

This systematic study aims to assess the global epidemiologic, economic, and humanistic burden of illness associated with all types of hereditary angioedema.

METHODS

A systematic search for articles reporting the epidemiologic, economic, and humanistic burden associated with patients with HAE was conducted using English and Chinese literature databases from the inception to May 23, 2022. The selected studies were assessed for their quality and risk of bias. The study was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses and registered with the International Prospective Register of Systematic Reviews (PROSPERO; CRD42022352377).

RESULTS

In total, 65 articles that met the search inclusion criteria reported 10,310 patients with HAE, of whom 5861 were female patients. Altogether, 4312 patients (81%) and 479 patients (9%) had type 1 and type 2 HAE, respectively, whereas 422 patients (8%) had HAE-normal C1-INH. The overall prevalence of all types of HAE was between 0.13 and 1.6 cases per 100,000. The mean or median delay from the first onset of a symptom of HAE to confirmed diagnosis ranged from 3.9 to 26 years. The estimated risk of death from asphyxiation was 8.6% for patients with HAE. Hospitalization, medication, unnecessary surgeries, doctor visits, specialist services, and nursing costs are direct expenses that contribute to the growing economic burden. The indirect cost accounted mostly due to missing work ($3402/year) and loss of productivity ($5750/year). Furthermore, impairment of QoL as reported by patient-reported outcomes was observed. QoL measures identified depression, anxiety, and stress to be the most common symptoms for adult patients and children.

CONCLUSION

This study highlights the importance of early diagnosis and the need for improving awareness among health care professionals to reduce the burden of HAE on patients and society.

Complex analysis of the national Hereditary angioedema cohort in Slovakia - Identification of 12 novel variants in SERPING1 gene

Background

Hereditary angioedema (HAE) is a rare autosomal dominant genetic disease characterised by acute episodes of non-pruritic skin and submucosal swelling caused by increase in vascular permeability.

Objective

Here we present the first complex analysis of the National HAE Slovakian cohort with the detection of 12 previously un-published genetic variants in SERPING1 gene.

Methods

In patients diagnosed with hereditary angioedema caused by deficiency or dysfunction of C1 inhibitor (C1-INH-HAE) based on clinical manifestation and complement measurements, SERPING1 gene was tested by DNA sequencing (Sanger sequencing/massive parallel sequencing) and/or multiplex ligation-dependent probe amplification for detection of large rearrangements.

Results

The Slovakian national cohort consisted of 132 living patients with confirmed HAE. We identified 51 index cases (32 families, 19 sporadic patients/112 adults, 20 children). One hundred seventeen patients had HAE caused by deficiency of C1 inhibitor (C1-INH-HAE-1) and 15 patients had HAE caused by dysfunction of C1 inhibitor (C1-INH-HAE-2). The prevalence of HAE in Slovakia has recently been calculated to 1:41 280 which is higher than average calculated prevalence. The estimated incidence was 1:1360 000. Molecular-genetic testing of the SERPING1 gene found 22 unique causal variants in 26 index cases, including 12 previously undescribed and unreported.

Conclusion

The first complex report about epidemiology and genetics of the Slovakian national HAE cohort expands the knowledge of the C1-INH-HAE genetics. Twelve novel causal variants were present in the half of the index cases. A higher percentage of inframe variants comparing to other studies was observed. Heterozygous deletion of exon 3 found in a large C1-INH-HAE-1 family probably causes the dysregulation of the splicing isoforms balance and leads to the decrease of full-length C1-INH level.

Clinical Characteristics and Quality of Life in a Cohort of Polish Pediatric Patients with Hereditary Angioedema

Hereditary angioedema (HAE) is a rare genetic disease. It is characterized by recurrent attacks of angioedema. Evidence to what extent it affects patient functioning is limited in the pediatric population. We aimed to determine the clinical characteristics and management of Polish children with HAE and to measure the health-related quality of life (HRQoL) of these patients. This cross-sectional study was conducted among 21 pediatric patients and their caregivers, as well as 21 respective controls randomly selected from the general population. During routine follow-up visits, standardized pediatric quality of life questionnaires (PedsQLTM 4.0) were administered to all caregivers and adolescents (≥13 years). Caregivers also completed a structured medical interview regarding the clinical characteristics and treatment of children with HAE during the previous six months. During this period, 57% of patients had low (group I), 24% moderate (group II), and 19% high (group III) HAE activity, corresponding to ≥10 attacks per 6 months. None of the patients received long-term prophylaxis. The children in group III had a lower HRQoL than other groups and controls on all dimensions of the PedsQLTM 4.0. The lowest scores in all groups were observed in the emotional functioning domain. Our data demonstrate that the burden of HAE on the quality of life of pediatric patients and their families encompasses a wide range of daily functioning.

The multifactorial impact of receiving a hereditary angioedema diagnosis

Hereditary angioedema (HAE) is a rare, chronic, debilitating genetic disorder characterized by recurrent, unpredictable, and potentially life-threatening episodes of swelling that typically affect the extremities, face, abdomen, genitals, and larynx. The most frequent cause of HAE is a mutation in the serpin family G member 1 (SERPING1) gene, which either leads to deficient plasma levels of the C1-esterase inhibitor (C1-INH) protein (type I HAE-C1-INH) or normal plasma levels of dysfunctional C1-INH protein (type II HAE-C1-INH). Mutations in SERPING1 are known to be associated with dysregulation of the kallikrein-bradykinin cascade leading to enhancement of bradykinin production and increased vascular permeability. However, some patients present with a third type of HAE (HAE-nl-C1-INH) that is characterized by normal plasma levels and functionality of the C1-INH protein. While mutations in the factor XII, angiopoietin-1, plasminogen, kininogen-1, myoferlin, and heparan sulfate-glucosamine 3-O-sulfotransferase-6 genes have been identified in some patients with HAE-nI-C1-INH, genetic cause remains unknown in many cases with further research required to fully elucidate the pathology of disease in these patients. Here we review the challenges that arise on the pathway to a confirmed diagnosis of HAE and explore the multifactorial impact of receiving a HAE diagnosis. We conclude that it is important to continue to raise awareness of HAE because delays to diagnosis have a direct impact upon patient suffering and quality of life. Since many patients will seek help from hospitals during their first swelling attack it is vital that emergency department staff are aware of the different pathological pathways that distinguish HAE from other forms of angioedema to ensure that the most appropriate treatment is administered. As disease awareness increases, it is hoped that patients will be diagnosed earlier and that pre-authorization and insurance coverage of HAE treatments will become easier to obtain, ultimately reducing the burden of treatment for these patients and their caregivers.

Hereditary angioedema (HAE) in Belgium: results from a national survey

Background

Hereditary angioedema (HAE) is a rare heritable disorder that is characterized by recurrent, circumscribed, nonpitting, nonpruritic, often painful subepithelial swellings of sudden unpredictable onset that generally fade during 48-72 h. Epidemiological data of hereditary angioedema patients in Belgium is lacking.

Methods

We set up a nation-wide, multicentric study involving the 8 Belgian hospitals known to follow-up patients with Type I and II HAE. All Belgium HAE patients were asked to fill out questionnaires that mainly covered demographic data, family history, and detailed information about diagnosis, treatment and burden of their Type I and II HAE.

Results

112 patients with type I or type II HAE could be included. Median delay between first symptoms and diagnosis was 7 years. 51% of patients had experienced pharyngeal or tongue swelling and 78% had experienced abdominal symptoms, both known to cause an important reduction in quality of life. 60% of symptomatic patients reported to receive long term prophylactic treatment. Human plasma-derived C1-esterase inhibitor concentrate was used by 56.3% of patients. 16.7% and 27.1% of patients used a 17-α-alkylated androgen and tranexamic acid as long term prophylactic therapy.

Conclusions

We present the first nation-wide epidemiological study regarding HAE in Belgium. Our data show that the morbidity of HAE is not to be underestimated. Knowledge and dissemination of this data is critical in raising awareness, encouraging development of therapies and optimising nationwide management.

Clinical outcomes of hereditary angioedema on multiparous women

OBJECTIVE

Significant concerns for patients with hereditary angioedema (HAE) include hormonal fluctuations and drug safety during pregnancy. The impact of the disease on childbearing in multiparous women remains to be elucidated. We aimed to investigate the clinical course and impacts of multiparity on HAE patients.

STUDY DESIGN

This observational study included 15 multiparous women with HAE; a total of 88 pregnancies were assessed using a questionnaire and the patient's medical records.

RESULTS

The median age was 36 (IQR, 33-39). Of 72 resulted in healthy babies without any congenital abnormalities. In sixteen pregnancies, 12 (13.6%) ended with spontaneous abortion; three resulted in stillbirth and one neonatal death. Two-thirds of the patients (n = 10) enounced a worsening in the frequency of angioedema attacks during pregnancy. There was no statistically significant difference compared with the nonpregnant period (p = 0.283). One-fifth of the patients (n = 3) reported alleviation in attacks. While most deliveries were vaginally (n = 57 babies), 19 deliveries in six patients were by cesarean section. None of the patients were aware of the diagnosis of HAE prior to their first pregnancies. After the diagnosis was made, eight patients received 263 vials of plasma-derived C1-inhibitor concentrate during a total of 13 pregnancies. No adverse events were reported.

CONCLUSION

We conclude that our results on clinical course and outcomes of HAE in multiparous patients are consistent with the literature. A greater focus on multiparous HAE patients could produce exciting findings.

A catalog of the genetic causes of hereditary angioedema in the Canary Islands (Spain)

Hereditary angioedema (HAE) is a rare disease where known causes involve C1 inhibitor dysfunction or dysregulation of the kinin cascade. The updated HAE management guidelines recommend performing genetic tests to reach a precise diagnosis. Unfortunately, genetic tests are still uncommon in the diagnosis routine. Here, we characterized for the first time the genetic causes of HAE in affected families from the Canary Islands (Spain). Whole-exome sequencing data was obtained from 41 affected patients and unaffected relatives from 29 unrelated families identified in the archipelago. The Hereditary Angioedema Database Annotation (HADA) tool was used for pathogenicity classification and causal variant prioritization among the genes known to cause HAE. Manual reclassification of prioritized variants was used in those families lacking known causal variants. We detected a total of eight different variants causing HAE in this patient series, affecting essentially SERPING1 and F12 genes, one of them being a novel SERPING1 variant (c.686-12A>G) with a predicted splicing effect which was reclassified as likely pathogenic in one family. Altogether, the diagnostic yield by assessing previously reported causal genes and considering variant reclassifications according to the American College of Medical Genetics guidelines reached 66.7% (95% Confidence Interval [CI]: 30.1-91.0) in families with more than one affected member and 10.0% (95% CI: 1.8-33.1) among cases without family information for the disease. Despite the genetic causes of many patients remain to be identified, our results reinforce the need of genetic tests as first-tier diagnostic tool in this disease, as recommended by the international WAO/EAACI guidelines for the management of HAE.

Clinical Characteristics and Management of Angioedema Attacks in Polish Adult Patients with Hereditary Angioedema Due to C1-Inhibitor Deficiency

Hereditary angioedema (HAE) due to C1-inhibitor (C1-INH) deficiency is a rare disease characterized by recurrent swellings. This study aims to determine (i) the clinical characteristics of the HAE patient population from Poland, and (ii) real-life patients' treatment practices. A cross-sectional study involved 138 adult HAE patients (88 females, 50 males) treated in six regional HAE centers in Poland. Consecutive patients during routine follow-up visits underwent a structured medical interview on the clinical characteristics of the course and treatment of HAE attacks within the last six months. A total of 118 of 138 patients was symptomatic. They reported in total 2835 HAE attacks predominantly peripheral and abdominal, treated with plasma-derived C1-INH (61.4%), icatibant (36.7%) and recombinant C1-INH (1.9%). An amount of 116 patients carried the rescue medication with them while traveling, and 74 patients self-administrated on demand treatment. There were twice as many symptomatic women (n = 78) as there were men (n = 40). Women treated their HAE attacks significantly more often than men. Older patients (≥65 years) reported a longer delay in diagnosis, and practiced the self-administration of rescue medication less frequently in comparison to other patients. Clinical features of the surveyed population are similar to other European, but not Asian, HAE patient groups. Self-administration still remains an unmet medical need. Some distinct HAE patients may require special attention due to the severe course of the disease (females) or a delay in diagnosis (the elderly).

First Census of Patients with Hereditary Angioedema in the Canary Islands

Hereditary angioedema (HAE) is a rare genetic condition whose main symptoms are recurrent swelling in the skin, mucosa, and internal organs. Recent studies suggested that the regulation of the inflammatory response and the complement cascade are two of the pathways significantly enriched in the Canary Islands, Spain. Here, we describe the first HAE patient series in this region. Forty-one patients (33 F, 8 M) and nine healthy relatives belonging to twenty-nine families were recruited for this study, obtaining their clinical and demographic features using a data collection form, as well as blood samples for biochemical analysis. The mean age of patients was 36.8 years (ranging from 4 to 72 years). Positive family history of HAE was reported in 13 patients (32.5%), and a mean diagnosis delay of 7.9 (±12.5) years was estimated, ranging from months to 50 years. Cutaneous edema was the most common symptom (53.6%), while airway symptoms was present in 11 patients. Prophylactic treatment was indicated for 23 patients, while 14 also require on-demand rescue treatment. We estimate a minimum prevalence of 1.25:100,000 for HAE due to C1-INH deficiency or dysfunction in the Canary Islands, which is higher than the estimates for mainland Spanish populations. HAE continues to be a disease poorly recognized by health care professionals due to its confusing symptoms, leading to longer diagnosis delay. Altogether, the evidence reinforces the need for a rapid and accurate diagnosis and precision medicine-based studies to improve the patient's quality of life.

The Global Registry for Hereditary Angioedema due to C1-Inhibitor Deficiency

Hereditary angioedema (HAE) is a rare condition, mostly due to genetic deficiency of complement C1 inhibitor (C1-INH). The rarity of HAE impedes extensive data collection and assessment of the impact of certain factors known to affect the course of this disabling and life-threatening disease. Establishing a global registry could assist to overcome such issues and provides valuable patient data from different countries. The HAE Global Registry is a disease-specific registry, with web-based electronic support, where data are provided by physicians and patients through a dedicated application. We collected data between January 1, 2018, and August 31, 2020. Data on 1297 patients from 29 centers in 5 European countries were collected. At least one attack was recorded for 497 patients during the study period. Overall, 1182 patients were diagnosed with HAE type 1 and 115 with type 2. At the time of database lock, 389 patients were taking long-term prophylactic medication, 217 of which were on danazol. Most recorded attacks affected the abdomen, were generally moderate in severity, and occurred in patients who were not on prophylactic treatment (70.6%, 6244/8848). The median duration of attacks was 780 min (IQR 290-1740) in patients on prophylactic medication and 780 min (IQR 300-1920) in patients not on continuous prophylactic medication. In conclusion, the establishment of a registry for C1-INH-HAE allowed collection of a large amount of data that may help to better understand the clinical characteristics of this disease. This information may enhance patient care and guide future therapeutic decisions.

The diagnosis and treatment of hereditary angioedema patients in Japan: A patient reported outcome survey

BACKGROUND

The rate at which patients are accurately diagnosed with hereditary angioedema (HAE), as well as diagnosed patients access to modern treatments differs greatly among countries. Moreover, the severity and burden of HAE on patients have been reported mostly on the basis of physician-reported surveys. To gain insight into the real-world conditions of patients with HAE through a patient-reported survey in Japan and identify any unmet needs.

METHODS

A questionnaire was distributed to 121 patients with HAE via a Japanese HAE patient organization during 2016-2017. Responses were collected from 70 patients (57.9%) and subjected to analysis.

RESULTS

The average periods from the initial appearance of symptoms (e.g. edema) to a HAE diagnosis was 15.6 years (min-max, 0-53). Patients visited an average of 4.6 different departments until receiving a definitive diagnosis. The average age at the first visit was 25.6 years (3-73) and at diagnosis 32.8 years (0-73). Patients reported an average of 15.7 (0-100) attacks per year, but only 53.1% of attacks were treated. The days of hospitalization due to severe attacks was 14.3 (0-200) before diagnosis, but these declined to 4.3 (0-50) after diagnosis. In the treatment for attacks, 82% of the patients were treated with the plasma-derived C1 inhibitor concentrate, and 69% of the patients reported experiencing a therapeutic effect.

CONCLUSIONS

There is a long gap between first attack and diagnosis of HAE, and the number of non-treated attacks is high in Japan. Steps are needed to improve the diagnostic and treatment environments to address these issues.

Novel SERPING1 gene mutations and clinical experience of type 1 hereditary angioedema from North India

BACKGROUND

There is paucity of literature on long-term follow-up of patients with hereditary angioedema (HAE) from developing countries.

OBJECTIVE

This study was carried out to analyze the clinical manifestations, laboratory features, and genetic profile of 32 patients (21 male and 11 female) from 23 families diagnosed with HAE between January 1996 and December 2019.

METHODS

Data were retrieved from medical records of Paediatric Immunodeficiency Clinic, Postgraduate Institute of Medical Education and Research, Chandigarh, India.

RESULTS

Median age at onset of symptoms was 6.25 years (range 1-25 years), and median age at diagnosis was 12 years (range 2-43 years). Serum complement C4 level was decreased in all patients. All patients had low C1-esterase inhibitor (C1-INH) quantitative level (type 1 HAE). SERPING1 gene sequencing could be carried out in 20 families. Of these, 11 were identified to have a pathogenic disease-causing variant in the SERPING1 gene. While 2 of these families had a previously reported mutation, remaining 9 families had novel pathogenic variants in SERPING1 gene. Because of non-availability of C1-INH therapy in India, all patients were given long-term prophylaxis (attenuated androgens or tranexamic acid (TA) or a combination of the 2). Life-threatening episodes of laryngeal edema were managed with fresh-frozen plasma (FPP) infusions. We recorded one disease-related mortality in our cohort. This happened in spite of long-term prophylaxis with stanozolol and TA.

CONCLUSIONS

We report largest single-center cohort of patients with HAE from India. Attenuated androgens, fibrinolytic agents, and FPP may be used for management of HAE in resource-limited settings.

Hereditary angioedema in Austria: prevalence and regional peculiarities

Background

Data on the prevalence and clinical features of Austrian patients with hereditary angioedema (HAE) with C1‐inhibitor (C1‐INH) deficiency (HAE‐1) or dysfunction (HAE‐2) are lacking.

Methods

Current baseline data were collected in a national survey. The records of HAE patients at the Medical University of Graz were analyzed with regard to clinical characteristics.

Results

A total of 137 patients were identified, yielding a prevalence of 1 : 64,396. The median age at the onset of symptoms was 6.5 years, and the median age at the time of correct diagnosis 21.0 years. The median delay in diagnosis was 15.0 years for newly diagnosed patients without a family history of HAE. Patients with a family history of HAE received an immediate diagnosis. HAE patients without a family history of HAE and born before 1960 had to wait a median of 16.0 years until they were diagnosed correctly. Patients born after 1980 still experienced a median diagnostic delay of 6.5 years.

Conclusion

Patients with this condition still face an excessive diagnostic delay in some parts of Austria, or their disorder may even remain unrecognized by specialists. This underlines the need for better awareness of the disease.

Epidemiology of Bradykinin-mediated angioedema: a systematic investigation of epidemiological studies

Background

Bradykinin-mediated angioedema (Bk-AE) can be life-threatening and requires specific targeted therapies. Knowledge of its epidemiology may help optimize its management.

Methods

We systematically searched the medical literature to identify abstracts of interest indexed between 1948 and March, 2016. We used published national survey data on the proportion of the population treated with angiotensin-converting enzyme inhibitors (ACEI) to derive estimates of the population prevalence of ACEI-AE in the USA, Germany and France. For hereditary angioedema (C1-INH-HAE) and C1-inhibitor related acquired angioedema (C1-INH-AAE), publications had to contain original epidemiologic data collection within a defined geographical area. Hereditary angioedema with normal C1-INH was not included in the analysis due to lack of clearly defined criteria.

Results

We identified 4 relevant publications on the prevalence of ACEI-AE, 6 on the prevalence of C1-INH-HAE, and 1 on the prevalence of C1-INH-AAE. The 1st year cumulative incidence of ACEI-AE was estimated to vary between 0.12 (population-based analyses) and 0.30 (meta-analyses of clinical trials) per 100 patient-years. The population prevalence of ACEI-AE was modeled to vary between 7 and 26 in 100,000. The prevalence of C1-INH-HAE was estimated to vary between 1.1 and 1.6 per 100,000. The prevalence of C1-INH-AAE was estimated to be 0.15 per 100,000 in one epidemiological investigation of AAE in Denmark.

Conclusions

Epidemiological evidence on Bk-AE is limited to North America and Europe. ACEI-AE is more common than C1-INH-HAE (~ 10:1), which is more common than C1-INH-AAE (~ 10:1). More studies are needed to comprehensively assess the epidemiological burden of Bk-AE.

Burden of Illness and Quality-of-Life Measures in Angioedema Conditions

Burden of illness studies and evaluation of health-related quality of life using validated questionnaires have become an important task in the comprehensive management of angioedema conditions, mainly angioedema associated with chronic spontaneous urticaria and hereditary angioedema caused by C1-inhibitor deficiency. A review of the principal tools and studies is presented. Both diseases present a higher proportion of psychiatric disorders, impair work and studies productivity, and produce high direct and indirect costs. These assessments also have been useful to evaluate the positive impact of new drugs and interventions. More studies are desirable, especially in other types of angioedema disorders, such as hereditary angioedema with normal C1 inhibitor.

Clinical Features of Hereditary and Mast Cell-mediated Angioedema Focusing on the Differential Diagnosis in Japanese Patients

Objective The present study was designed to identify the clinical characteristics that permit the differential diagnosis of hereditary angioedema (HAE) and mast cell-mediated angioedema (Mast-AE) during the first consultation. Methods The medical histories and laboratory data of 46 patients with HAE and 41 patients with Mast-AE were compared. Results The average age of onset in the HAE group (19.8±9.0 years) was significantly lower than that in the Mast-AE group (35.2±12.0 years). The incidence of familial angioedema (AE) in the HAE group (73.9%) was significantly higher than that in the Mast-AE group (9.7%). The frequency of history of AE in the extremities, larynx, or gastrointestinal tract was significantly higher in the HAE group. The frequency of AE episodes of the lips and eyelids was significantly lower in the HAE group. The serum C4 concentration and CH50 titer were lower than the normal limit in 91.3% and 45.6% of the patients in the HAE group, respectively; in Mast-AE group the serum C4 concentration and CH50 titer were significantly lower than the normal limit in 4.8% and 0% of the patients, the difference between the two groups was statistically significant. A C1-inhibitor (C1-INH) activity level of <50% was observed in all of the HAE patients, but none of the Mast-AE patients. The mean serum IgE titer in the HAE group (120.8±130.5 IU/mL) was significantly lower than that in the Mast-AE group (262.2±314.9 IU/mL). Conclusion The parameters within the patients' medical histories, such as the age at the onset of AE, a family history of AE, and the locations of past AE episodes are critical for the successful diagnosis of the disease. Measurements of the C4 and C1-INH activity are very useful for differential diagnosis of HAE from Mast-AE.

Registries as useful tools in characterization of allergic manifestations

PURPOSE OF REVIEW

Registries are useful to discover the applicability of data generated from randomized clinical trials (RCTs) into daily practice, and to search for real-life data usually not covered by them.

RECENT FINDINGS

In allergy, registry research brought clues to important epidemiological and clinical problems hardly accessible with other methods. The increase in the asthma prevalence in Sweden in contrast with stabilization in Denmark; the association of the prevalence of asthma and environmental factors; the knowledge of existing rhinitis international guidelines, but the poorly complacence of some of their recommendations; the low epinephrine use in anaphylaxis and the difference among European and Latin American elicitors; the predominance of β lactams or NSAIDs as drug hypersensitivity reactions inducers in different regions; the fact that most of the hereditary angioedema patients were receiving long-term prophylaxis with attenuated androgens; all the mentioned are clear examples of relevant and important data provided by current registries.

SUMMARY

Registries in allergy enlighten knowledge in areas not covered by classical investigational methods. As the number and importance of registries is growing, its contribution to the knowledge and management of allergic diseases will increase in the near future.

The Humanistic, Societal, and Pharmaco-economic Burden of Angioedema

Hereditary angioedema due to C1 inhibitor deficiency (C1-INH-HAE) is a rare disorder characterized by intermittent and unpredictable episodes of swelling which cause disfigurement, disability, pain, or, in case of laryngeal swelling, risk of death. Historical factors, including the intermittent nature of the disorder, the lack of awareness of this ultra-rare condition amongst medical personnel, lack of specialist centers, and limited treatment options have contributed to under-diagnosis and under-treatment of the condition. Incorrect treatment of attacks has been common, even when medical help is sought. This has lead to reduced health-seeking behavior and alternative coping strategies, sometimes even denial, in many families, while a minority of HAE-affected patients have become serial emergency room attenders with chronic pain and ongoing requirement for opiate-based painkillers. Both strategies have incurred not only physical but also psychological and economic consequences.In the last 10 years, new and effective acute therapies have been made available, some of which have also provided short-term and long-term prophylaxis options, together with a better understanding of older prophylactic drugs. Improved awareness of HAE amongst the general public, family members, and physicians has reduced the long delay in diagnosis and increased the number of patients receiving effective and up-to-date therapies to improve the physical impact of the disorder.Data on the impact of treatment on the psychological outcomes is scarce, but the limited information available suggests that access to specialist advice and treatment leads to psychological as well as physical improvement.HAE also has profound effects on individual and family economic output, directly via absenteeism from school or work and indirectly via lost opportunities. Economic improvements associated with better treatments are offset by the high cost of new acute treatments, resulting in difficult pharmaco-economic calculations. Worldwide, cost considerations present potentially insurmountable barriers to treatment for many patients, depending on the healthcare system in the individual country.

Pediatric Hereditary Angioedema: Onset, Diagnostic Delay, and Disease Severity

Hereditary angioedema (HAE) typically presents in childhood. Large gaps remain in our understanding of the natural history of HAE during childhood. We examined age of onset, delay in diagnosis, androgen exposure, and their influence on ultimate disease severity in a large cohort of patients with HAE. Median age of first swelling was 11 years with a median age at diagnosis of 19 years. Earlier onset of symptoms correlated with longer delays in diagnosis (P < .001) and predicted a more severe disease course, including increased number of attacks per year (P = .0009) and hospital admissions (P = .009). Earlier age of onset also significantly correlated with increased perceived HAE severity (P = .0002), negative overall life impact (P < .0001), and use of anabolic androgen. Our observations highlight the importance of early HAE diagnosis and suggest the necessity of a disease management plan once the diagnosis has been made.

Management of acute attacks of hereditary angioedema: role of ecallantide

Hereditary angioedema (HAE) is characterized as an episodic swelling disorder with autosomal dominant inheritance. Clinical features include nonpitting edema of external or mucosal body surfaces, and patients often present with swelling of the extremities, abdominal pain, and swelling of the mouth and throat, which can lead to asphyxiation. Patients with HAE classically have no associated urticaria, which is often referred to as nonhistaminergic angioedema. Treatment for HAE involves long-term prophylaxis, short-term prophylaxis, and management of acute attacks. Up until the past few years, acute HAE episodes were predominately treated with supportive measures. Three classes of medications have recently been approved by the US Food and Drug Administration (FDA) for the management of acute HAE attacks. Ecallantide, a recombinant protein that acts as a reversible inhibitor of kallikrein, is currently indicated for acute attacks of HAE in those aged ≥12 years. In two randomized, double-blind, placebo-controlled, multicenter trials, EDEMA3 and EDEMA4, patients treated with 30 mg of ecallantide demonstrated statistically significant improvement in symptoms compared to those on placebo. In addition to its use as treatment for HAE, ecallantide has been used off label in the management of nonhistaminergic angioedema, not due to HAE. Ecallantide has shown promise in the treatment of these other forms; however, data are limited to mainly case reports at this time. Ecallantide is generally a safe and well-tolerated medication; however, based on reports of anaphylaxis, ecallantide does contain a black box warning. Due to the risk of anaphylaxis, ecallantide cannot be self-administered and must be given by a health care professional. Overall, ecallantide is a safe and effective medication for the treatment of acute attacks of HAE.

Clinical manifestations, diagnosis, and treatment of hereditary angioedema: survey data from 94 physicians in Japan

BACKGROUND

Hereditary angioedema (HAE) is a rare and potentially life-threatening condition that results from mutations in the C1 inhibitor (C1-INH). Awareness of HAE among physicians in Japan is increasing, but real-world data are lacking.

OBJECTIVE

To explore the clinical manifestations, diagnosis, quality of life (QOL), and treatment of Japanese patients with HAE.

METHODS

A 14-point survey was developed and sent to 387 physicians in Japan (March to May 2014) to gather clinical data on their HAE patients' family history, severity and frequency of attacks, QOL, and therapy use.

RESULTS

Data on 171 HAE patients were collected from 94 physicians (24.3% response rate). Of the patients, 76.6% had a family history of angioedema (AE), and 11.7% had experienced a death in the family due to an AE attack. HAE type I occurred in 99 patients (57.9%), HAE type II occurred in 9 patients (5.3%), HAE with normal C1-INH occurred in 3 patients (1.8%), and an additional 60 patients were unclassified. Mean time from initial symptoms to diagnosis was 13.8 years. Attacks that required airway management and abdominal surgery with uncertain diagnosis were observed in 9.5% and 2.9% of patients, respectively. In the past year, 21.0% of patients presented with more than 10 attacks, 21.1% were admitted to the hospital for more than 1 day, and 28.7% were absent from work or school. On-demand C1-INH concentrate and prophylactic tranexamic acid were used in approximately half of the patients (47.4% and 39.2%, respectively).

CONCLUSION

HAE is a severe condition characterized by recurrent AE attacks. In Japan, delayed patient diagnosis and limited use of HAE-specific therapies exacerbate the burden on HAE patients.