Presentation, diagnosis and treatment of angioedema without wheals: a retrospective analysis of a cohort of 1058 patients

Patients With Chronic Spontaneous Urticaria Who Have Wheals, Angioedema, or Both, Differ Demographically, Clinically, and in Response to Treatment-Results From CURE

BACKGROUND

Patients with chronic spontaneous urticaria (CSU) have spontaneous wheals (W), angioedema (AE), or both, for longer than 6 weeks. Clinical differences between patients with standalone W, standalone AE, and W and AE (W+AE) remain incompletely understood.

OBJECTIVE

To compare W, AE, and W+AE CSU patients regarding demographics, disease characteristics, comorbidities, disease burden, and treatment response.

METHODS

Baseline data from 3,698 CSU patients in the ongoing, prospective, international, multicenter, observational Chronic Urticaria REgistry (CURE) were analyzed (data cut: September 2022).

RESULTS

Across all CSU patients, 59%, 36%, and 5% had W+AE, W, and AE, respectively. The W+AE patients, compared with W and AE patients, showed the lowest male-to-female ratio (0.33), higher rates of concomitant psychiatric disease (17% vs 11% vs 6%, respectively), autoimmune disease (13% vs 7% vs 9%, respectively), and nonsteroidal anti-inflammatory drug (NSAID) hypersensitivity (9% vs 5% vs 2%, respectively) and the highest disease impact. The W patients, compared with W+AE and AE patients, showed the lowest rates of concomitant hypertension (15% vs 21% vs 40%, respectively) and obesity (11% vs 16% vs 17%, respectively), the highest rate of concomitant inducible urticaria (24% vs 22% vs 6%, respectively), and shorter W duration. The AE patients, compared with W+AE and W patients, were older at disease onset, showed longer AE duration, and the best response to increased doses of H1-antihistamines (58% vs 24% vs 31%, respectively) and omalizumab (92% vs 67% vs 60%, respectively).

CONCLUSIONS

Our findings provide a better understanding of CSU phenotypes and may guide patient care and research efforts that aim to link them to pathogenic drivers.

Real-world experience of hereditary angioedema (HAE) in Mexico: A mixed-methods approach to describe epidemiology, diagnosis, and treatment patterns

Introduction and objectives

Due to the lack of structured and systematic information available, the aim of this study was to describe the epidemiology, diagnosis, healthcare processes, and treatment patterns of hereditary angioedema (HAE) in Mexico. To achieve this, different data sources were consulted regarding medical literature, structured health system databases, and angioedema-specialized physicians (AEP) opinion regarding HAE.

Material and methods

A mixed methods approach was conducted in 4 phases: I) systematic literature review (SLR) and meta-analysis according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines; II) review of national health system (NHS) databases and systematic reports; III) physician survey; and IV) an epidemiologic model. ICD 10 D84.1 encoded records from the NHS were used to estimate the number of patients with HAE attended and treated during 2019. A survey was implemented to increase understanding of the clinical profile and treatments used.

Results

A prevalence rate of 0.9/50 000 inhabitants was estimated for 2019. In the same year, an estimated 317 HAE type 1 patients were recorded in the NHS, aged ≥11 years old. The most frequent clinical symptoms were cutaneous edema (67.5%) and abdominal pain (47.9%). A severe episode with laryngeal edema appeared in 27.5% of cases. Acute episodes were mainly moderate to severe (77.0%), with an annual per capita frequency of emergency visits of 7.6 patient-year (range 1-12/patient-year). The main reasons for hospitalization corresponded to laryngeal facial, tongue, and abdominal edemas, representing 73.3% of annual ICD 10 D84.1 reported hospitalizations. The main treatments that patients with HAE received were fresh frozen plasma for acute attacks and danazol for short-term prophylaxis (STP).

Conclusions

Despite efforts to make HAE visible, according to this study, cases recognized and treated in the NHS represent only 16.6% of the estimated prevalence.

Acquired Non-histaminergic Angioedema With C1q Autoantibody and Urticaria: A Case Report

Acquired angioedema (AAE) is a rare disease with life-threatening complications. This pathology has classically been associated with medication use and B cell lymphoproliferative disorders. In this report, we describe a 61-year-old man with a six-year history of angioedema, unrelated to any known triggers or malignancy. Extensive workup has led to a diagnosis of idiopathic nonhistaminergic AAE with normal C1 inhibitor. The patient is currently being treated with lanadelumab, which has resolved the patient's symptoms. This case provides insight into the onset, exploration, treatment, and outcomes of an extremely rare disease process.

A safety review of prophylaxis drugs for adolescent patients with hereditary angioedema

INTRODUCTION

Hereditary angioedema (HAE) is characterized by recurrent subcutaneously and/or submucosally localized edematous swellings. The first symptoms often appear in childhood, and they may become more frequent and severe in puberty. Since the appearance of HAE attacks is unpredictable regarding the localization and the frequency, the attacks put a significant burden on the patients and crucially impacts their quality of life.

AREAS COVERED

This review article analyzes the safety data acquired from the clinical trials conducted with the currently available medicinal products for the prophylactic treatment of hereditary angioedema due to C1 inhibitor deficiency and the safety data of observatory studies based on clinical practice. A review of the published literature was conducted using the PubMed database, clinical trials from ClinicalTrials.gov, and abstracts published at scientific conferences.

EXPERT OPINION

The currently available therapeutic products have a good safety and efficiency profile and the international guidelines recommend them as first-line treatments. The choice should be made based on the evaluation of the availability and the preference of the patient.

Pediatric Angioedema without Wheals: How to Guide the Diagnosis

Angioedema (AE) is a vascular reaction of subcutaneous and submucosal tissues that identifies various clinical pictures and often is associated with wheals. AE without wheals (AEwW) is infrequent. The ability to distinguish between AEwW mediated by mast cells and bradykinin-mediated or leukotriene-mediated pathways is often crucial for a correct diagnostic-therapeutic and follow-up approach. AEwW can be hereditary or acquired. Factors typically correlated with hereditary angioedema (HAE) are a recurrence of episodes, familiarity, association with abdominal pain, onset after trauma or invasive procedures, refractoriness to antiallergic therapy, and lack of pruritus. The acquired forms of AE can present a definite cause based on the anamnesis and diagnostic tests. Still, they can also have an undetermined cause (idiopathic AE), distinguished according to the response to antihistamine in histamine-mediated and non-histamine-mediated forms. Usually, in childhood, AE responds to antihistamines. If AEwW is not responsive to commonly used treatments, it is necessary to consider alternative diagnoses, even for pediatric patients. In general, a correct diagnostic classification allows, in most cases, optimal management of the patient with the prescription of appropriate therapy and the planning of an adequate follow-up.

A comparative study of chronic spontaneous urticaria and chronic mast cell mediated angioedema

Background: Mast cell-mediated angioedema (MC-AE) is considered a form of chronic spontaneous urticaria (CSU). Objective: To investigate the clinical and laboratory features that distinguish MC-AE from antihistamine-responsive CSU (CSU), and antihistamine-resistant CSU (R-CSU) with and without concomitant AE. Methods: A retrospective observational study using the electronic patient record data base of patients with MC-AE, CSU, R-CSU, and sex- and age-matched control group (control), with a case-control ratio of 1:2. Results: A total of 986 subjects in the CSU group, 148 in the R-CSU group, 64 in the MC-AE group, and 1198 in the control group were compared. The R-CSU group without AE was characterized by lower total IgE levels (118.5 ± 84.7 IU/mL) and higher High sensitivity-C reactive protein (hs-CRP) levels (138.9 ± 94.2 IU/mL, p = 0.027; and 7.4 ± 6.9 mg/L versus 5.1 ± 6.8 mg/L, p = 0.001) than the CSU without AE group. The R-CSU group with AE was characterized by lower total IgE levels (112.1 ± 81.3 IU/mL) than the CSU group with AE (141.7 ± 89.5 IU/mL; p < 0.001), higher hs-CRP levels (7.1 ± 6.1 mg/L versus 4.7 ± 5.9 mg/L; p < 0.001). There were fewer female subjects in the MC-AE group (31 [48.4%]) than in the CSU with AE and in the R-CSU with AE 223 (67.8%) and 18 (66.7%), respectively; p = 0.012). MC-AE group was characterized by less eyelid/perioral/facial involvement and more limb involvement than in the CSU with AE and R-CSU with AE groups (p < 0.001). Conclusion: Low IgE in MC-AE and higher IgE in CSU may signify two distinct types of immune dysregulation. Due to clinical and laboratory differences between MC-AE and CSU, we suggest questioning the assumption that MC-AE is a form of CSU.

C1-inhibitor/C1-inhibitor antibody complexes in acquired angioedema due to C1-inhibitor deficiency

BACKGROUND

Autoantibodies against C1-inhibitor (C1-INH-Ab) have a diagnostic value in acquired angioedema due to C1-inhibitor deficiency (C1-INH-AAE), even though antibodies can circulate in complexes, which can be undetectable by proven methods. Our aim was to measure C1-INH/C1-INH-Ab complexes (CAC) and investigate their connection to C1-INH-Ab and the changes in their titer over time.

RESULTS

19 patients were diagnosed with C1-INH-AAE in the Hungarian Angioedema Center of Reference and Excellence; 79% of them had an underlying disease. Samples were examined with a newly developed in-house complex ELISA method. Patients with high C1-INH-Ab titer had a CAC titer which did not exceed the normal level and the ones with high CAC titer had a C1-INH-Ab titer which did not exceed the normal level. In case of those patients who had C1-INH-Ab and CAC of the same type of immunoglobulin, the increasing titer of C1-INH-Ab went together with the decreasing level of CAC and vice versa. CAC titer was already increased before the diagnosis of the underlying disease.

CONCLUSIONS

Free circulating and complex antibodies are in a dynamically changing equilibrium. CAC measurements can help to predict the development of an underlying disease. The efficiency of the treatment for underlying disease can be monitored by the decreasing CAC titers. Our results show that the CAC can be of important additional information besides the complement panel examination in case of C1-INH-AAE. Measurement of CAC is recommended to be done parallelly with C1-INH-Ab, so as to detect both free and bound antibodies.

Profile of serious angioedema requiring an urgent advice from a national reference call center

Angioedema (AE) is a reason for emergency care when it is severe. Care is difficult when the diagnostic is not known before the attack: mast cell (MC) or bradykinin (BK) mediated. One is very common but often benign, the other rare but potentially fatal. The French national reference center of angioedema (CREAK) provides emergency physicians with a hotline and a guideline to help them manage their patients. This study aimed to describe the clinical features of AE episodes prompting a call on the CREAK hotline and classify patients depending on the suspected cause of the AE. This is a retrospective study between March and August 2019. Each physician calling on the CREAK hotline was asked to fill a clinical description form for the AE emergency. Known patients of CREAK was excluded. Eighty four patients were included. Forty one (48.8%) in the angiotensin converting enzyme inhibitors induced acquired angioedema (ACEi-AAE), 39 (46.4%) in the mast cell induced angioedema, and 4 (4.8%) in the Bradykinin mediated angioedema. The mast cell induced angioedema patients have more history of hives (29.3%) than ACEi-AAE (2.4%, P = .0004). ACEi-AAE mainly affected the tongue (58.5% vs 25.6%, P = .003) and larynx (29.3% vs 13%, P = .001). In 65.5% of cases, the etiological diagnosis was not mentioned by the appellant, but made by the hotline. In 31% of cases, the hotline suggested the administration of a specific treatment not previously provided by the caller. All the doctors who called the hotline appreciate this tele-expertise especially in case of ACEi-AAE presumptions. In addition to providing rapid AE expertise, this service also allows to educate physicians in the management of AE irrespective of its origin.

Omalizumab for Treatment of Idiopathic Angioedema

BACKGROUND

Omalizumab has been shown to improve outcomes in patients with chronic spontaneous urticaria (CSU). Idiopathic angioedema (IAE) is increasingly being recognized as a condition with similar underlying mechanisms as CSU and a form of CSU. We hypothesized that add-on therapy with omalizumab would benefit patients with uncontrolled IAE.

OBJECTIVE

To study the safety and efficacy of omalizumab for the treatment of IAE in adults.

METHODS

We conducted a randomized, placebo-controlled trial to study the efficacy of omalizumab in adults with two or more episodes of angioedema (AE) in the past 6 months for which no clinical or laboratory cause of AE could be found. Ten patients were randomized on a 1:1 basis to receive omalizumab 300 mg SQ or placebo every 4 weeks for 24 weeks with a 12 week follow up period. The primary endpoint was the change in the Angioedema Activity Score (AAS). Secondary endpoints included the Angioedema Quality of Life Questionnaire (AE-QoL), the Visual Analog Scale (VAS) and the number of angioedema episodes per month.

RESULTS

We observed improvement in the AAS score (-2.93 ln odds; 95% confidence interval (CI) -4.84, -1.02; p = 0.003), VAS (-3.49 ln odds; 95% CI -6.58, -0.40; p = 0.03), AE-QoL (-9.43 score; 95% CI -17.63, -1.24; p = 0.028) and number of angioedema episodes per month (-1.93 ln count; 95% CI -3.23, -0.63; p = 0.005) in patients that received omalizumab vs placebo.

CONCLUSION

This study provides preliminary prospective evidence that omalizumab improves outcomes in patients with IAE.

Differences and Similarities in the Mechanisms and Clinical Expression of Bradykinin-Mediated vs. Mast Cell-Mediated Angioedema

Angioedema (AE), transient localized swelling due to extravasated fluid, is commonly classified as mast cell mediator-induced, bradykinin-mediated or of unknown cause. AE often occurs more than once, and it is these recurrent forms of AE that are challenging for patients and physicians, and they are the ones we focus on and refer to as AE in this review. Since effective treatment depends on the causative mediator, reliable and early diagnosis is essential. Although their clinical presentations bear similarities, many forms of angioedema exhibit specific patterns of clinical appearance or disease history that may aid in diagnosis. Here, we describe the most common differences and similarities in the mechanisms and clinical features of bradykinin-mediated and mast cell mediator-induced types of angioedema. We first provide an overview of the diseases that manifest with mast cell mediator-induced versus bradykinin-mediated angioedema as well as their respective underlying pathogenesis. We then compare these diseases for key clinical features, including angioedema location, course and duration of swelling, attack frequency, prevalence and relevance of prodromal signs and symptoms, triggers of angioedema attacks, and other signs and symptoms including wheals, age of onset, and duration. Our review and comparison of the clinical profiles of different types of angioedema incorporate our own clinical experience as well as published information. Our aim is to highlight that mast cell mediator-induced and bradykinin-mediated angioedema types share common features but are different in many aspects. Knowledge of the differences in underlying pathomechanisms and clinical profiles between different types of angioedema can help with the diagnostic approach in affected patients and facilitate targeted and effective treatment.

Gastrointestinal manifestations of angioedema: a potential area of misdiagnosis

Abdominal pain is one of the most common conditions leading people to the emergency department. An uncommon but well described cause of abdominal pain is angioedema of the gastrointestinal tract due to recurrent angioedema without wheals. Abdominal involvement is very common in hereditary angioedema (HAE), but it is also described in acquired angioedema and allergic forms. In patients with HAE, the involvement of gastrointestinal tract with resultant abdominal pain occurs in 43-93% of cases. Attacks can involve the entire gastrointestinal tract, such as the oropharynx, small intestine, colon, liver, or pancreas. Pain is the most common gastrointestinal symptom, and it may occur for many years even without cutaneous or respiratory symptoms. The case report we included in this article emphasizes the importance of accurate evaluation of personal and family history in patients with a long history of acute, severe, and unexplained abdominal pain, and it gives an example of how diagnostic delay may be longer if gastroenterological symptoms are the predominant clinical presentation. Furthermore, sometimes the simultaneous presence of concomitant gastrointestinal disorders and HAE may cause difficulties in differential diagnosis. Gastroenterologists and other physicians should add HAE to their list of potential causes of unexplained abdominal pain. The initiation of appropriate prophylaxis and treatment will prevent needless suffering and useless surgical and medical procedures.

A Comparative Study of Sex Distribution, Autoimmunity, Blood, and Inflammatory Parameters in Chronic Spontaneous Urticaria with Angioedema and Chronic Histaminergic Angioedema

BACKGROUND

Recurrent idiopathic histaminergic angioedema is currently classified as a subtype of angioedema, as well as a subtype of chronic spontaneous urticaria (CSU), based on the fact that both are mast cell-mediated and respond to the same treatments.

OBJECTIVE

In the present work, we sought to verify whether chronic histaminergic angioedema (CHA) is an entity distinct from CSU or represents a CSU subtype that lacks hives.

METHODS

We performed a prospective study comparing 68 CHA patients, angioedema without hives, with 63 CSU patients, with hives and angioedema, from whom we collected demographic and clinical data, as well as blood and serum markers.

RESULTS

We found key pathogenic features that differentiate CHA from CSU: gender distribution, basophil number, and antibodies against the IgE receptor. The male/female ratio in CHA was 0.78, whereas in CSU it was 0.36 (P = .0466). Basopenia was more often seen in CSU (n = 13 [20%]) than in CHA (n = 5 [7%]). Finally, 31.15% of CSU sera induced basophil activation, whereas no CHA sera were able to activate normal basophils. By contrast, nonspecific inflammation or immune markers, for example, erythrocyte sedimentation rate, C-reactive protein, or IgG antithyroid antibodies, were very similar between both groups. IgE anti-IL-24 could not be assessed because a control population did not differ from CSU.

CONCLUSIONS

Inclusion of CHA as part of the spectrum of CSU is an assumption not evidence-based, and when studied separately, important differences were observed. Until there is further evidence, CHA and CSU should not necessarily be considered the same disorder, and it is our opinion that review articles and guidelines should reflect that possibility.

A follow-up survey of patients with acquired angioedema due to C1-inhibitor deficiency

BACKGROUND

Acquired angioedema due to C1-inhibitor deficiency (C1-INH-AAE) is a rare form of bradykinin-mediated angioedema. It is diagnosed by complement testing; its treatment consists of the management of angioedema (AE) attacks and of underlying disease.

OBJECTIVE

Evaluate the results of the clinical follow-up of patients with C1-INH-AAE.

METHODS

Between 1999 and 2020, 3938 patients with angioedema were evaluated, and 17 diagnosed with acquired C1-INH deficiency were followed-up.

RESULTS

Mean age of the 17 patients was 61 years at diagnosis. In 33%, ACE inhibitors provoked AE attacks. Autoantibodies against C1-INH were detected in 10 patients at diagnosis and in a further patient during follow-up. The AE attacks involved the skin in 70.6%, the upper airways in 41.2% and the tongue/lip in 52.9% of patients. Twelve of the 17 patients had an underlying condition, mainly (n = 11) lymphoproliferative disease. In 10 patients diagnosed with a haematological disorder, AAE symptoms preceded the onset of the latter. One patient has not experienced an AE attack since diagnosis. Twelve patients were treated for angioedema attacks, and 32% of the attacks required acute treatment. PdC1-INH was used to relieve AE attacks, and rituximab for the treatment of underlying disease (in six patients). Six patients had multiple AE attacks before any treatment. The symptom-free period increased in five patients after the on-demand administration of pdC1-INH concentrate and following treatment of the underlying disease in two patients.

CONCLUSION

Early diagnosis of C1-INH-AAE and underlying disease is indispensable to reduce disease burden by introducing appropriate, individualized treatment and regular follow-up.

Recurrent angioedema: Experience at a tertiary care urban medical center

OBJECTIVE

To determine the demographics, presentation, management, and outcomes of patients with recurrent angioedema. To compare the findings to patients with ACE inhibitor related angioedema.

METHODS

Retrospective case series with chart review of patients who presented to a tertiary-care hospital between January 2010 and December 2017 with two or more episodes of angioedema. Excluded were patients with anaphylactic reaction, medication induced angioedema, or angioedema secondary to an infectious etiology. A group of 88 patients who presented during the same time period with ACE inhibitor related angioedema was used as a control. Statistical analysis was conducted using a two-tailed Fisher exact test and a multivariate logistical regression model to determine significant associations.

RESULTS

Ninety-one patients were identified; 61 met the selection criteria and had 217 total episodes of angioedema episodes presenting to the emergency department. Fifty percent were Caucasian or Hispanic. The average number of episodes was 3.5 (range: 2-23). The lips and tongue were the most commonly affected sites (37% and 39%). The larynx and floor of mouth were least likely to be involved (7% and 6%). Only 1 patient was found to have C1 esterase inhibitor deficiency. Twenty-eight percent of patients had asthma, allergic rhinitis, food allergies, or atopic dermatitis. Only 11% of episodes required airway intervention. No patients required airway intervention after admission.

CONCLUSION

Recurrent angioedema was primarily idiopathic, was less severe than ACE inhibitor angioedema, and was associated with an atopic history. There was less frequent worsening of symptoms after admission, and recurrences occurred more frequently are at the same anatomic subsite.

LEVEL OF EVIDENCE

IV.

Leveraging Genetics for Hereditary Angioedema: A Road Map to Precision Medicine

Biochemical studies performed during the last decades resulted in the development of various innovative medicinal products for hereditary angioedema (HAE). These therapeutic agents target the production or the function of bradykinin-the main mediator of HAE due to C1-inhibitor (C1-INH) deficiency. However, despite these remarkable achievements, current knowledge cannot provide convincing explanations for the clinical variability of the disease. As a consequence, treatment indications apply for drugs available for C1-INH deficiency. The advent of high-throughput next-generation sequencing technologies may assist in covering the missing part of our understanding of HAE pathogenesis. During the last 3 years alone, several new entities were added to the already described genotypes. The recent discovery of four novel target genes expands our understanding of other causes which may explain recurrent angioedema in individuals and families with normal C1-INH activity. Furthermore, new genetic technologies allowed the recognition of deep intronic variants associated with the disease, and elegant functional studies characterized new variants for the C1-INH gene. Thus, evidence has been provided regarding pathogenetic aspects remaining obscure for many years, such as the defective intracellular transport of mutant C1-INH, and environmental effect on the disease expression. Therefore, it seems that the stage for Precision Medicine era in HAE management is ready. Disease endotypes are expected to be uncovered and specified targets for therapeutic intervention will be detected, promising a more effective, individualized management of the disease.

The Panorama of Primary Angioedema in the Brazilian Population

BACKGROUND

Primary angioedema (PA) is a complex disorder, presenting multiple hereditary (hereditary angioedema) and acquired subtypes (acquired angioedema). Despite a very similar clinical presentation among subtypes, the differential diagnosis is limited by the difficulty to identify bradykinin-mediated PA and the lack of specific biomarkers.

OBJECTIVES

To report the clinical and genetic features of Brazilian patients with PA.

METHODS

Brazilian patients referred from 50 centers were diagnosed on the basis of clinical symptoms, C1 inhibitor (C1-INH) and C4 plasma measurements, and DNA sequencing of genes associated with hereditary angioedema.

RESULTS

We characterized 92 patients with acquired angioedema and 425 with HAE: 125 with C1-INH deficiency, 180 with F12 mutations, and 120 of unknown cause. Thirty-one different mutations were identified in SERPING1 and 2 in F12, in addition to 2 mutations of uncertain significance in the ANGPT1 gene. The molecular diagnosis was decisive for 34 patients with HAE without family history, and for 39% of patients with inconsistent biochemical measurements. The median delay in diagnosis was 10 years, with a maximum of 18 years for HAE with C1-INH deficiency. Androgens and tranexamic acid were the most used drugs for long-term prophylaxis in all the PA subtypes, and they were used on demand by 15% of patients. Only 10% of patients reported the use of specific medication for HAE during attacks.

CONCLUSIONS

Our analysis exposes a broad picture of PA diagnosis and management in a developing country. Complement measurements presented considerable inconsistencies, increasing the diagnosis delay, while patients with PA with normal C1-INH remain with an inaccurate diagnosis and unspecific treatment.

Hereditary angioedema: Differential diagnosis, diagnostic tests, and family screening

Hereditary angioedema is a rare, autosomal dominant genetic disorder that leads to sporadic episodes of swelling, which can affect any part of the body. With a prevalence of 1 in 10,000 to 1 in 50,000, there are other, more common causes of angioedema. Differentiating between bradykinin-mediated and histamine-mediated causes of swelling remains a major challenge. It is critical to develop an appropriate differential diagnosis, work through the various conditions, and obtain the pertinent laboratory evaluation to rule in or out the proposed diagnosis. As an autosomal dominant genetic disorder, there is a 50% chance with each pregnancy of passing on the genetic mutation in the SERPING1 gene. This review addressed the differential diagnosis to consider, the appropriate laboratory evaluation, and the importance of family screening.

Hereditary angioedema: Epidemiology and burden of disease

<title/> Hereditary angioedema (HAE) is a rare autosomal dominant genetic disorder characterized by swelling of subcutaneous, mucosal, and submucosal tissue without associated pruritus or wheals caused by a temporary localized increase in vascular permeability. Swelling attacks primarily affect the cutaneous tissue, abdominal viscera, genitals, or airways. <title/> Reports of the prevalence of HAE C1 inhibitor (C1-INH) deficiency varies widely, from 1:50,000 to 1:100,000. The prevalence of HAE normal C1-INH is unknown but is likely much lower than HAE C1-INH. Approximately one-third of patients with recurrent angioedema without wheals have HAE. <title/> The burden of disease for patients with HAE is substantial. Attacks are unpredictable with respect to frequency, severity, and the site that swells. Laryngeal attacks can be fatal if not treated promptly and appropriately. Feelings of stress, anxiety, and depression can trigger attacks, and begin a cycle of attacks that cause anxiety that, in turn, triggers further attacks. Despite full physical recovery between attacks, patients often experience continual emotional impairment and reduced quality of life (QoL). Absenteeism from work and presenteeism at work or educational activities for patients and caregivers increase stress and reduce productivity during and between attacks. Missed opportunities for career development are common. <title/> Significant advances have been made in the past decade to expand both acute and prophylactic treatment options for patients with HAE, lowering both the disease and treatment burden, and improving the QoL of patients with HAE.

Clinical features of genetically characterized types of hereditary angioedema with normal C1 inhibitor: a systematic review of qualitative evidence

BACKGROUND

Hereditary angioedema (HAE) with normal C1 inhibitor (C1-INH) (HAEnCI) is associated with skin swellings, abdominal attacks, and the risk of asphyxia due to upper airway obstruction. Several different gene mutations linked to the HAE phenotype have been identified. Our aim was to qualitatively assess and describe the clinical differentiators of these genetically identified HAEnCI types. To achieve this, we performed a systematic literature review of patients with angioedema symptoms and a genetically confirmed diagnosis of an HAEnCI type.

RESULTS

A systematic literature search, conducted in March 2020, returned 132 records, 43 of which describe patients with symptoms of angioedema and a genetically confirmed diagnosis of an HAEnCI type. Overall, this included 602 patient cases from 220 families. HAEnCI with a mutation in the coagulation factor XII gene (F12) (HAE-FXII) was diagnosed in 446 patients from 185 families (male:female ratio = 1:10). Estrogens (oral contraceptives, hormonal replacement therapy, and pregnancy) negatively impacted the course of disease in most female patients (252 of 277). Asphyxia occurred in 2 of 446 patients. On-demand and/or long-term prophylaxis treatment included C1-INH concentrates, icatibant, progestins, and tranexamic acid. HAEnCI with a specific mutation in the plasminogen gene (HAE-PLG) was diagnosed in 146 patients from 33 families (male:female ratio = 1:3). Estrogens had a negative influence on the course of disease in the minority of female patients (14 of 62). Tongue swelling was an important clinical feature. Asphyxia occurred in 3 of 146 patients. On-demand treatment with icatibant and C1-INH concentrate and long-term prophylaxis with progestins and tranexamic acid were effective. HAEnCI with a specific mutation in the angiopoietin-1 gene (HAE-ANGPT1) was diagnosed in 4 patients from 1 family and HAEnCI with a specific mutation in the kininogen-1 gene (HAE-KNG1) in 6 patients from 1 family.

CONCLUSIONS

A number of clinical differentiators for the different types of HAEnCI have been identified which may support clinicians to narrow down the correct diagnosis of HAEnCI prior to genetic testing and thereby guide appropriate treatment and management decisions. However, confirmation of the causative gene mutation by genetic testing will always be required.

Clinical Features and Disease Course of Primary Angioedema Patients in a Tertiary Care Hospital

Purpose

To give a better understanding of primary AE, the clinical characteristics and the possible therapeutic approaches.

Background

Angioedema (AE) is a non-pitting, non-itching swelling of skin or mucosa. The symptom can become life-threatening if located in the airways. Primary (monosymptomatic) AE is a manifestation of several different diseases and the diagnosis is not always straight-forward. The aetiological and pathophysiological factors of primary AE are not completely clarified. There is a need for further investigation.

Patients and Methods

This was a retrospective cohort study of patients referred to an outpatient dermatology clinic in a tertiary care hospital for clinical assessment due to primary AE in the period from 1996 to 2014.

Results

A total of 315 patients were identified with primary AE. The most frequent subtype was idiopathic AE (42.5%) and the second most common was angiotensin-converting enzymeinhibitor (ACEi)-induced AE (31.1%). Three patients were diagnosed with hereditary AE and one patient was diagnosed with acquired C1-inhibitor deficiency. At least 107 (34.0%) patients had established histaminergic AE. More than 1/3 of the patients were treated in an emergency room or hospitalized due to AE. A 98.1% of patients had experienced AE in the head and neck area. Seven patients were in the need of acute airway intervention. Six of these had ACEi-induced AE. Female sex and smoking were found to be risk factors for developing AE.

Conclusion

The most frequent diagnoses were histaminergic-, non-histaminergic idiopathic AE and ACEi-induced AE, whereas complement C1-inhibitor deficiency was rare. Histaminergic AE made up a substantial group of patients with primary AE. Even though there are different pathophysiological causes of AE, many cases have overlapping clinical manifestations, which make diagnosis and treatment difficult.

Impaired control of the contact system in hereditary angioedema with normal C1-inhibitor

BACKGROUND

Hereditary angioedema (HAE) comprises HAE with C1-inhibitor deficiency (C1-INH-HAE) and HAE with normal C1-INH activity (nl-C1-INH-HAE), due to mutations in factor XII (FXII-HAE), plasminogen (PLG-HAE), angiopoietin 1 (ANGPT1-HAE), kininogen 1 genes (KNG1-HAE), or angioedema of unknown origin (U-HAE). The Italian network for C1-INH-HAE (ITACA) created a registry including different forms of angioedema without wheals.

OBJECTIVE

We analyzed clinical and laboratory features of a cohort of Italian subjects with nl-C1-INH-HAE followed by ITACA to identify specific biomarkers.

METHODS

A total of 105 nl-C1-INH-HAE patients were studied. Plasma concentrations of cleaved high-molecular-weight kininogen (cHK), vascular endothelial growth factors (VEGFs), angiopoietins (Angs), and secreted phospholipase A₂ enzymes (sPLA₂ ) were evaluated.

RESULTS

We identified 43 FXII-HAE patients, 58 U-HAE, and 4 ANGPT1-HAE. We assessed a prevalence of 1:1.4 × 10⁶ for FXII-HAE and 1:1.0 × 10⁶ for U-HAE. cHK levels in U-HAE patients were similar to controls in plasma collected using protease inhibitors cocktail (PIC), but they significantly increased in the absence of PIC. In FXII-HAE patients, cHK levels, in the absence of PIC, were significantly higher than in controls. We found a significant increase of VEGF-A, VEGF-C, and Ang1 levels in U-HAE patients compared to controls. In FXII-HAE, only VEGF-C levels were increased. Ang2 concentrations and sPLA₂ activity were not modified. The levels of these mediators in ANGPT1-HAE patients were not altered.

CONCLUSIONS

Our results suggest that pathogenesis of FXII-, ANGPT1-, and U-HAE moves through an unbalanced control of kallikrein activity, with bradykinin as most likely mediator. VEGFs and Ang1 participate in the pathophysiology of U-HAE increasing the basal vascular permeability.

Design and characterization of α1-antitrypsin variants for treatment of contact system-driven thromboinflammation

The contact system produces the inflammatory peptide bradykinin and contributes to experimental thrombosis. C1 esterase-inhibitor (C1INH) deficiency or gain-of-function mutations in factor XII (FXII) cause hereditary angioedema, a life-threatening tissue swelling disease. C1INH is a relatively weak contact system enzyme inhibitor. Although α1-antitrypsin (α1AT) does not naturally inhibit contact system enzymes, a human mutation (M358R; α1AT-Pittsburgh) changes it into a powerful broad-spectrum enzyme inhibitor. It blocks the contact system, but also thrombin and activated protein C (APC), making it an unattractive candidate for therapeutic contact system blockade. We adapted the reactive center loop of α1AT-Pittsburgh (AIPR/S) to overcome these obstacles. Two α1AT variants (SMTR/S and SLLR/S) strongly inhibit plasma kallikrein, activated FXII, and plasmin. α1AT-SMTR/S no longer inhibits thrombin, but residually inhibits APC. In contrast, α1AT-SLLR/S residually inhibits thrombin, but no longer APC. Additional modification at the P1' position (S→V) eliminates residual inhibition of thrombin and APC for both variants, while retaining their properties as contact system inhibitors. Both α1AT-SMTR/V and -SLLR/V are superior to C1INH in reducing bradykinin production in plasma. Owing to their capacity to selectively block contact system-driven coagulation, both variants block vascular occlusion in an in vivo model for arterial thrombosis. Furthermore, both variants block acute carrageenan-induced tissue edema in mice. Finally, α1AT-SLLR/V, our most powerful candidate, suppresses epithelial leakage of the gut in a mouse model of colitis. Our findings confirm that redesign of α1AT strongly alters its inhibitory behavior and can be used for the treatment of contact system-mediated thrombosis and inflammation.

ACE inhibitor-mediated angioedema

Angioedema (AE) occurring during ACE inhibitor therapy (ACEi-AE) is a rare complication involving between 0.1 and 0.7% of treated patients. AE can also complicate other therapeutic regimens that block the renin-angiotensin aldosterone system. Other drugs, such as immune suppressors, some type of antidiabetics or calcium antagonists, can increase the likelihood of ACEi-AE when associated to ACEi. There is a clear ethnic predisposition, since African-Americans or Hispanics show a higher prevalence of this condition compared to Caucasians. At least in African-Americans the genetic predisposition accounts for a general higher prevalence of AE, independently from the cause. People that experience ACEi-AE may have some recurrence when they are switched to an angiotensin-receptor blocker (ARB); however, epidemiological studies on large cohorts have shown that angiotensin receptor blockers (ARB) do not increase the likelihood of AE compared to other antihypertensives. Clinical manifestations consist of edema of face, lips, tongue, uvula and upper airways, requiring intubation or tracheotomy in severe cases. Attacks last for 48-72 h and require hospital admission in most cases. Intestinal involvement with sub-occlusive symptoms has also been reported. The pathogenesis of ACEi-AE depends mainly on a reduced catabolism and accumulation of bradykinin, which is normally metabolized by ACE. Genetic studies have shown that some single nucleotide polymorphisms at genes encoding relevant molecules for bradykinin metabolism and action may be involved in ACEi-AE, giving a basis for the ethnic predisposition. Treatment of ACEi-AE is still a matter of debate. Corticosteroids and antihistamines do not show efficacy. Some therapeutic attempts have shown some efficacy for fresh frozen plasma or C1 inhibitor concentrate infusion. Interventional studies with the specific bradykinin receptor antagonist icatibant have shown conflicting results; there might be a different ethnic predisposition to icatibant efficacy which has been proven in caucasian but not in black patients.

The rash that presents as a red swollen face

A red swollen face can be a skin sign of a potentially life-threatening condition. We present in detail the main clinical presentations, diagnostic tests, and management of some of the most severe conditions that can frequently present as a red and swollen face: acute or recurrent angioedema, mast cell-driven or bradykinin-mediated angioedema, nonhereditary and hereditary angioedema, allergic or photoallergic facial contact dermatitis, contact urticaria, severe adverse drug reactions (particularly drug reaction with eosinophilia and systemic symptoms [DRESS]), skin infections (erysipelas, cellulitis, necrotizing fasciitis), and autoimmune diseases (dermatomyositis). There are many other conditions that also have to be considered in the differential diagnosis of a red swollen face.

Bradykinin signaling regulates solute permeability and cellular junction organization in lymphatic endothelial cells

OBJECTIVE

Determine the effect of bradykinin on solute permeability and cellular junctional proteins in human dermis microvascular endothelial cells.

METHODS

Cells were characterized by immunofluorescence and fluorescence-activated cell sorting. Macromolecular transport of dextran and albumin was monitored. Junctional protein expression and phosphorylation were determined by immunoblot analyses. Intracellular calcium and cAMP levels were evaluated. Target gene expression at mRNA and protein levels was determined.

RESULTS

Human dermis microvascular endothelial cells comprised 97% lymphatic endothelial cells. Bradykinin increased the permeability to dextran in a concentration-dependent manner, while reduced the permeability to albumin. Bradykinin treatment down-regulated VE-cadherin expression and affected its phosphorylation status at Tyr731. It also down-regulated claudin-5 expression at the transcriptional level through bradykinin-2-receptor signaling. An increase in the intracellular calcium levels and a reduction in the cAMP concentration were associated effects. Finally, bradykinin induced the up-regulation of vascular endothelial growth factor-C protein which was found increased in BK-induced human dermis microvascular endothelial cells culture supernates.

CONCLUSIONS

Human dermis microvascular endothelial cells represent a model of lymphatic endothelial cells, in which bradykinin-2-receptor is expressed. Bradykinin-induced bradykinin-2-receptor signaling through intracellular calcium mobilization and reduction in cAMP levels, triggered changes in solute permeability and cellular junction expression. It further up-regulated vascular endothelial growth factors-C protein expression, which is a key modulator of lymphatic vessels function and lymphangiogenesis.

Bradykinin-Mediated Angioedema: An Update of the Genetic Causes and the Impact of Genomics

Recurrent episodes of bradykinin-mediated angioedema (Bk-AE) can associate with acquired or hereditary conditions, the former most commonly developing secondarily to a pharmacological treatment. Despite successful genomic advances that have led to the identification of a large number of disease genes irrespective of disease prevalence, their application to Bk-AE has barely occurred. As a consequence, the genetic causes of Bk-AE remain poorly understood, obstructing the identification of patient subtypes and the development of precision medicine strategies. This review provides an update of the genetic studies completed to date on the acquired forms, which have almost exclusively focused on Bk-AE secondarily to the angiotensin-converting enzyme inhibitor treatment, and the blooming subdivision of the hereditary forms established by the identification of novel causal genes with next-generation sequencing (NGS) technology-based exome studies in genetically undiagnosed patients. Finally, based on the diverse benefits that are offered by the technology, we present arguments favoring the use of holistic NGS approaches as first-tier genetic tests as a promise to reduce the diagnostic odyssey of patients with suspected hereditary forms of Bk-AE.

High occurrence of antihistamine resistance in patients with recurrent idiopathic angioedema

Antihistamines are the most prescribed therapy in recurrent idiopathic angioedema, yet little is known about their efficacy. Herein, we report on clinical improvement with antihistamine therapy in 120 patients evaluating angioedema attack frequency. A high incidence (36%) of antihistamine refractory cases was observed. Forty percent of patients on antihistamine prophylaxis suffered from 1 or more angioedema attacks per month. Our findings stress the need for additional treatment options for recurrent idiopathic angioedema.

Hereditary Angioedema: Insights into inflammation and allergy

Hereditary Angioedema (HAE) is a rare autosomal recessive bradykinin (BK)-mediated disease characterized by local episodes of non-pitting swelling. Initially considered a complement-mediated disease, novel pathogenic mechanisms uncovered in the last decade have revealed new HAE-associated genes and tight physiological relationships among complement, contact, coagulation, fibrinolysis and inflammation. Uncontrolled production of BK due to inefficient regulation of the plasma contact system, increased activity of contact and coagulation factors or a deficient regulation of BK receptor-triggered intracellular signalling are on the basis of HAE pathology. In this new scenario, HAE can result from different mechanisms that may generate distinct clinical phenotypes of the disease. This review focuses in the recent advances and unsolved challenges in our comprehension of this ever increasingly complex pathology.

Coagulation and Skin Autoimmunity

Several lines of evidence indicate that the immune system, inflammation, and coagulation are simultaneously activated in autoimmune and immune-mediated skin diseases. Pro-inflammatory cytokines such as interleukin-6 and tumor necrosis factor-alpha induce the expression of the main initiator of coagulation, i.e., tissue factor. The proteases of coagulation in turn act on protease-activated receptors inducing the expression of various pro-inflammatory cytokines triggering inflammation. The cross-talk among immune system, inflammation, and coagulation amplifies and maintains the activation of all three pathways. This review focuses on three skin disorders as chronic spontaneous urticaria (CSU), angioedema, and bullous pemphigoid (BP), in which the relationships among the three systems have been investigated or their clinical consequences are relevant. Markers of thrombin generation, fibrinolysis, and inflammation have been reported to be increased in the plasma during flares of CSU and angioedema, as well as in the active phase of BP, with the marker levels reverting to normal during remission. The coagulation activation seems to be important only at local level in CSU and angioedema while both at local and systemic levels in BP which is the only condition associated with an increased thrombotic risk. The prothrombotic state in autoimmune skin diseases raises the question of the indication of anticoagulant treatment, particularly in the presence of other cardiovascular risk factors.

Angioedema and emergency medicine: From pathophysiology to diagnosis and treatment

Angioedema is a self-limiting edema of the subcutaneous or submucosal tissues due to localised increase of microvascular permeability whose mediator may be histamine or bradykinin. Patients present to emergency department when angioedema involves oral cavity and larynx (life-threatening conditions) or gut (mimicking an acute abdomen). After initial evaluation of consciousness and vital signs to manage breathing and to support circulation if necessary, a simple approach can be applied for a correct diagnosis and treatment. Forms of edema such as anasarca, myxedema, superior vena cava syndrome and acute dermatitis should be ruled out. Then, effort should be done to differentiate histaminergic from non-histaminergic angioedema. Concomitant urticaria and pruritus suggest a histaminergic origin. Exposure to allergens and drugs (mainly ACE inhibitors and non steroidal anti-inflammatory drugs) should be investigated as well as a family history of similar symptoms. Allergic histaminergic angioedema has a rapid course (minutes) whereas non histaminergic angioedema is slower (hours). Since frequently the intervention needs to be immediate, the initial diagnosis is only clinical. However, laboratory tests can be subsequently confirmatory. Allergic angioedema is sensitive to standard therapies such as epinephrine, glucocorticoids and antihistamines whereas non histaminergic angioedema is often resistant to these drugs. Therapeutic options for angioedema due C1-inhibitor deficiencies are C1-inhibitor concentrates, icatibant and ecallantide. If these drugs are not available, fresh frozen plasma can be considered. All these medications have been used also in ACE inhibitor-induced angioedema with variable results thus they are not currently recommended whereas experts agree on the discontinuation of the causative drug.

Wolf in the sheep's clothing: intestinal angioedema mimicking infectious colitis

Hereditary angioedema (HAE) is a relatively rare clinical entity that can potentially cause life-threatening airway or intestinal oedema, patients with the latter usually presents with symptoms of gastroenteritis like vomiting, diarrhoea and abdominal pain. Here, we present a unique case of a less recognised type of HAE that is type III in a patient who presented with signs and symptoms consistent with infectious colitis. She previously had similar episodes and was managed multiple times with antibiotics, with no satisfactory response. There, she underwent extensive diagnostic evaluation. On the basis of findings of further investigations on the current visit, she was eventually diagnosed with intestinal angioedema. To the best of our knowledge, the present paper represents the third reported case of type III HAE-induced intestinal angioedema. Additionally, we undertake a literature review of HAE.

Efficacy of Treatment of Non-hereditary Angioedema

Non-hereditary angioedema (AE) with normal C1 esterase inhibitor (C1INH) can be presumably bradykinin- or mast cell-mediated, or of unknown cause. In this systematic review, we searched PubMed, EMBASE, and Scopus to provide an overview of the efficacy of different treatment options for the abovementioned subtypes of refractory non-hereditary AE with or without wheals and with normal C1INH. After study selection and risk of bias assessment, 61 articles were included for data extraction and analysis. Therapies were described for angiotensin-converting enzyme inhibitor-induced AE (ACEi-AE), for idiopathic AE, and for AE with wheals. Described treatments consisted of ecallantide, icatibant, C1INH, fresh frozen plasma (FFP), tranexamic acid (TA), and omalizumab. Additionally, individual studies for anti-vitamin K, progestin, and methotrexate were found. Safety information was available in 26 articles. Most therapies were used off-label and in few patients. There is a need for additional studies with a high level of evidence. In conclusion, in acute attacks of ACEi-AE and idiopathic AE, treatment with icatibant, C1INH, TA, and FFP often leads to symptom relief within 2 h, with limited side effects. For prophylactic treatment of idiopathic AE and AE with wheals, omalizumab, TA, and C1INH were effective and safe in the majority of patients.

Omalizumab for Idiopathic Nonhistaminergic Angioedema: Evidence for Efficacy in 2 Patients

Presently, there is inconclusive evidence regarding the most effective treatment for idiopathic nonhistaminergic acquired angioedema (InH-AAE). Omalizumab may, however, prove to be a promising option. This case report describes two patients who presented with recurrent angioedema attacks, which was refractory to antihistamine therapy. Hence, they were treated with 300 mg omalizumab, every 4 weeks, for a period of 6 months. Both patients had shown a rapid response to the treatment and achieved complete resolution of symptoms without further AE attacks throughout the entire duration of the treatment period. After omalizumab's suspension, one patient remained symptom free for the following 6 months and the other patient had recurrence of symptoms after 2 months for which he was retreated with omalizumab and once again became symptom free. Although omalizumab seems to be effective as a prophylactic treatment for InH-AAE, the determining factors leading to the differences in time-to-relapse between patients after its suspension remain unclear. Further studies are needed in order to better determine the potential therapeutic application of omalizumab and its role in maintenance therapy.

Idiopathic Nonhistaminergic Acquired Angioedema Versus Hereditary Angioedema

BACKGROUND

The mechanism of idiopathic nonhistaminergic acquired angioedema (InH-AAE) has not yet been precisely elucidated. This condition is characterized by recurrent angioedema without wheals.

OBJECTIVE

To study the clinical features of InH-AAE, and to make, for the first time, independent comparisons with hereditary angioedema of unknown origin (U-HAE), as well as with hereditary angioedema with C1-inhibitor deficiency (C1-INH-HAE).

METHODS

We compared the clinical parameters of 46 patients with InH-AAE with those of 27 patients suffering from U-HAE, as well as of 73 patients with C1-INH-HAE.

RESULTS

The mean age at the onset of symptoms was 36 years in InH-AAE, 13 years in C1-INH-HAE, and 29 years in U-HAE. More than 12 edematous episodes occurred over a year in 56% of patients with InH-AAE, in 59% of those with C1-INH-HAE, and in 48% of those with U-HAE. Edema of the extremities, of the upper airways, and of the gastrointestinal tract was more common in patients with C1-INH-HAE (92%, 51%, and 75%, respectively). These manifestations occurred less frequently in patients with InH-AAE (54%, 28%, and 20%) and in patients with U-HAE (37%, 29%, and 20%). By contrast, facial edema occurred in only 15% of patients with C1-INH-HAE, but in 67% of patients with InH-AAE and in 59% of patients with U-HAE.

CONCLUSIONS

The clinical manifestations of patients with InH-AAE were different from those of patients with C1-INH-HAE. This may indicate different processes underlying edema formation in these disease forms. The close resemblance of the clinical manifestations in InH-AAE and U-HAE might suggest a similarity between the pathophysiology of these conditions.

Inhalant allergen sensitization is an independent risk factor for the development of angioedema

BACKGROUND/OBJECTIVE

The etiology and risk factors for angioedema remain poorly understood with causative triggers often going undiagnosed despite repeated reactions. The purpose of this study was to determine the relationship between inhalant allergen sensitization and angioedema.

METHODS

A retrospective review of patients who had in vitro inhalant allergy testing from 2006 to 2010 was performed. Patients with a diagnosis of angioedema who underwent inhalant allergy testing were identified. Analyses for co-morbidities, class of sensitization, seasonal timing of angioedema, and concurrent use of known hypertensive medications that can cause angioedema were performed.

RESULTS

There were 1000 patients who underwent inhalant allergy testing and qualified for the study. 37/1000 had at least one episode of angioedema and of these patients, 34 had positive inhalant sensitization testing results. Multivariate regression models showed overall sensitization status, seasonal allergen and epidermal/mite sensitization as independent risk factors (p<0.001, p=0.005, p=0.025 respectively) when controlling for ACE inhibitor use and other covariates. Tree, and epidermal/mite sensitizations were independent risk factors for angioedema in mono-sensitized subject analysis (p=0.028, p=0.029, respectively).

CONCLUSION

Both seasonal and perennial allergen sensitizations are independent risk factors for the development of angioedema. In patients with angioedema and an unknown trigger, inhalant allergen sensitization should be considered as a potential contributing factor to the development of angioedema.

Angioedema: Clinical Presentations and Pharmacological Management

Angioedema (AE) is a unique clinical presentation of an unchecked release of bradykinin. The origin of this clinical presentation can be either genetic or acquired. The outcome within the patient is subcutaneous swelling of the lower layers of the epidermis. Symptoms are most often localized to the upper airway or the gastrointestinal tract. A typical course resolves in 5 to 7 days, but in some patients, the clinical manifestations exist up to 6 weeks. Hereditary AE is rare and genetically linked, and typically, the patient has episodes for many years before diagnosis. Episodes of acquired AE may be drug induced, triggered by a specific allergen, or idiopathic. Angioedema can elicit the need for critical care interventions, for advanced airway management, or unnecessary abdominal surgery. The treatment for these patients is evolving as new pharmacological agents are developed. This article addresses subtypes of AE, triggers, pharmacology, and information for interdisciplinary team planning of individualized case management.

Idiopathic non-histaminergic acquired angioedema: a case series and discussion of published clinical trials

Background

Idiopathic non-histaminergic acquired angioedema (InH-AAE) is a rare disease for which there are no available laboratory parameters to clearly define the disorder. Therapy is often difficult and various treatment options have been proposed. In this paper, we have evaluated the most effective therapies for InH-AAE on the basis of current literature and report the therapeutic effect of omalizumab in three patients with InH-AAE.

Methods

Literature was searched with a combination of MeSH/EMTREE terms and freetext search for angioedema and therapy/omalizumab in the databases Medline (Ovid), PubMed/Premedline, Embase, Cochrane library and Scopus with no time or language restrictions. In three patients affected by InH-AAE the therapeutic effect of omalizumab was demonstrated by clinical outcome. In one patient the FcεRI receptor density on basophils was monitored under therapy with omalizumab.

Results

From the review of the current literature, 25 out of 286 publications dealing with relevant therapeutic recommendations for InH-AAE were analyzed. Six publications with 98 patients referred to tranexamic acid, of which 27 had a complete, 70 a partial and 1 no response. In three case reports ecallantide showed 2 patients with a complete and 1 a partial response. In four case reports for Icatibant 2 had a complete and 3 a partial response. When evaluated in three reports, C1-INH found complete and partial responses in 2 patients each. One patient had a complete response to progestin. Omalizumab was described in 6 reports with 20 patients, all of whom showed a complete response. All three patients described in our study responded to omalizumab with a complete remission. Density of FcεRI receptors on basophils, monitored in patient 1 on a long-term course of 31 months, decreased from 74,051.61 to a minimal level of 1907 receptors per cell.

Conclusions

Omalizumab seems to be the most effective therapy in InH-AAE. The continuous decrease of FcεRI-receptor density on basophils under therapy with omalizumab along with clinical improvement observed in one patient, could serve as a new approach for further studies to evaluate FcεRI-receptor density as a surrogate marker for therapeutic efficacy and for dosing and determining injection intervals of omalizumab.

Trial registration BASEC-Nr. Req-2016-00692. Retrospectively registered 24.11.2016.

Electronic supplementary material

The online version of this article (doi:10.1186/s13601-017-0164-9) contains supplementary material, which is available to authorized users.

Clinical Utility Gene Card for hereditary angioedema with normal C1 inhibitor (HAEnC1)

1. Name of the disease (synonyms)

Hereditary angioedema type III (HAE-III)

Estrogen-related hereditary angioedema

Hereditary angioedema with factor XII mutations (FXII-HAE)

Hereditary angioedema of unknown origin (U-HAE)

2. OMIM# of the disease

610618

3. Name of the analysed genes or DNA/chromosome segments:

Coagulation factor XII; Hageman factor; F12; chromosome 5q.35.2-q35.3

4. OMIM# of the gene(s)

610619

Review of the analytical and clinical validity as well as of the clinical utility of DNA-based testing for mutations in the F12 gene(s) in ⊠ diagnostic, ⊠ predictive and ⊠ prenatal settings and for, ⊠ risk assessment in relatives.

Angioedema suppressed by a combination of anti-histamine and leukotriene modifier

Rationale

Angioedema without co-existent urticaria is due to a limited number of causes, including hereditary and acquired C1 esterase inhibitor deficiency, drug-induced angioedema or idiopathic histaminergic or non-histaminergic angioedema. We describe a cohort of patients with recurrent angioedema whose clinical features and response to medications are distinct from the causes above.

Methods

Patients were accrued retrospectively from an academic allergy practice between 2007 and 2014. After institutional research ethics board approval, patients’ charts were reviewed and demographic, clinical and laboratory data were extracted.

Results

A total of 11 patients were recruited. The mean age at presentation was 54.9 years (range 19–70 years) and 6 of 11 were male. The mean number of episodes per year was 18.7 (range 2–60) and mean duration of episodes was 22.4 h (range 4–96). About half of episodes (52%) began overnight. Areas of involvement were lips (73%), tongue (64%), eyelids (18%), feet (36%) and hands (27%). None of the patients had low C3, C4, or CH50; none had significantly positive ANA; C1 esterase inhibitor level and function and C1q were normal in all patients tested. In these 11 patients, complete suppression of recurrences by the combination of cetirizine 20 mg daily and montelukast 10 mg daily was reported by 9 (82%) of patients; whereas 2 (18%) of patients had a partial response to this combination of medications.

Conclusions

Herein, we report a form of angioedema without urticaria, mediated by a combination of histamine and leukotrienes. Clinical, demographic and therapeutic characteristics differentiate this from other recognized causes of angioedema.

Acquired C1 Inhibitor Deficiency

Acquired angioedema due to C1-INH deficiency (C1-INH-AAE) can occur when there are acquired (not inherited) deficiencies of C1-INH. A quantitative or functional C1-INH deficiency with negative family history and low C1q is diagnostic of C1-INH-AAE. The most common conditions associated with C1-INH-AAE are autoimmunity and B-cell lymphoproliferative disorders. A diagnosis of C1-INH-AAE can precede a diagnosis of lymphoproliferative disease and confers an increased risk for developing non-Hodgkin lymphoma. Treatment focuses on symptom control with therapies that regulate bradykinin activity (C1-INH concentrate, icatibant, ecallantide, tranexamic acid, androgens) and treatment of any underlying conditions.