Exploring disease-specific metabolite signatures in hereditary angioedema patients.

Introduction: Hereditary angioedema (HAE) is a rare, life-threatening autosomal dominant genetic disorder caused by a deficient and/or dysfunctional C1 esterase inhibitor (C1-INH) (type 1 and type 2) leading to recurrent episodes of edema. This study aims to explore HAE patients' metabolomic profiles and identify novel potential diagnostic biomarkers for HAE. The study also examined distinguishing HAE from idiopathic angioedema (AE). Methods: Blood plasma samples from 10 HAE (types 1/2) patients, 15 patients with idiopathic AE, and 20 healthy controls were collected in Latvia and analyzed using LC-MS based targeted metabolomics workflow. T-test and fold change calculation were used to identify metabolites with significant differences between diseases and control groups. ROC analysis was performed to evaluate metabolite based classification model. Results: A total of 33 metabolites were detected and quantified. The results showed that isovalerylcarnitine, cystine, and hydroxyproline were the most significantly altered metabolites between the disease and control groups. Aspartic acid was identified as a significant metabolite that could differentiate between HAE and idiopathic AE. The mathematical combination of metabolites (hydroxyproline * cystine)/(creatinine * isovalerylcarnitine) was identified as the diagnosis signature for HAE. Furthermore, glycine/asparagine ratio could differentiate between HAE and idiopathic AE. Conclusion: Our study identified isovalerylcarnitine, cystine, and hydroxyproline as potential biomarkers for HAE diagnosis. Identifying new biomarkers may offer enhanced prospects for accurate, timely, and economical diagnosis of HAE, as well as tailored treatment selection for optimal patient care.

[Registry of Members of the Association of Patients with Hereditary Angioedema of Perú]. / Registro de miembros de la Asociación de Pacientes con Angioedema Hereditario de Perú.

OBJECTIVE: To report the registry of the HAE Peruvian patient's association. METHODS: We used the questionnaire of the Latin American HAE committee. Consent was requested from the patient's association to report the data. RESULTS: We report data of 63 patients, 51 Female, 12 Male, range age between 6 to 74 years. Nine under 18 years old, 5/9 between 6 to 13 years. Forty-five HAE C1-INH type I, 12 HAE-FXII, 5 HAE UNK, 1 AAE. Symptoms onset average age in 56/62 HAE patients was 16.8. In a group of 50/62 adult HAE patients, the average diagnostic delay approximately was 19.3 years. Laboratory tests: we can perform C4 complement C1-inhibitor antigenic and functional tests. Treatments: The patients have access to tranexamic acid (TA) and attenuated androgens. We do not have registered specific long-term prophylaxis treatments. We used moderate/high doses of TA, in most patients up to 6 gr i.v./in 24 hours, we start with the treatment immediately the HAE acute crisis is beginning, it helps to the HAE attacks are less symptomatic, resolves in a few days and decrease the frequency. CONCLUSIONS: We present 63 members of the Association of Patients with Hereditary Angioedema of Perú. We have improved blood tests for HAE diagnosis. Moderate and high doses of Tranexamic Acid are used for prophylaxis and acute crisis respectively, with acceptable response. No deaths have been reported due to HAE crisis in the patient's association.

OBJETIVO: Reportar el registro de pacientes de la Asociación de Pacientes con Angioedema Hereditario de Perú, AEH. MÉTODOS: Se utilizó el cuestionario del Comité de AEH, de la Sociedad Latinoamericana de Alergia, Asma e Inmunología (SLAAI). Se solicitó el consentimiento a la Asociación de Pacientes para reportar los datos. RESULTADOS: Se reportan datos de 63 pacientes, 51 mujeres y 12 hombres, en un rango de edad entre 6 y 74 años. Nueve menores de 18 años, 5/9, entre 6 y 13 años. 45 con AEH-C1-INH tipo I, 12 AEH-FXII, 5 AEH-D, 1 AEA. La edad promedio de inicio de síntomas en 56/62 pacientes fue de 16,8. En 50/62 pacientes adultos con AEH, el promedio de tiempo de espera en el diagnóstico fue de 19,3 años. Laboratorio: Se puede desarrollar C4 complemento, C1-Inhibidor antigénico y funcional. Tratamientos: Se cuenta con acceso al ácido tranexámico (AT) y andrógenos atenuados. No se cuenta con tratamientos específicos para profilaxis de largo plazo. Se utilizaron dosis moderadas/altas de (AT), hasta 6 g por I V/ en 24 horas, inmediatamente, al inicio de las crisis de AEH, ayuda a que los ataques no sean tan intensos y tengan menor duración y frecuencia. CONCLUSIONES: Se presentan 63 miembros de la Asociación de Pacientes con Angioedema Hereditario de Perú. Se han mejorado los exámenes sanguíneos para el diagnóstico del AEH. Se utilizaron dosis moderadas/altas de ácido tranexámico con aceptable respuesta en los pacientes. No se han presentado decesos por crisis de AEH en los miembros de la Asociación.

The Disease Burden of Hereditary Angioedema: Insights from a Survey in French-Canadians from Quebec.

Background: Limited data are available on the clinical profile and disease burden of hereditary angioedema (HAE) in Canadians. Objective: This study aimed to assess HAE disease characteristics and the burden of disease in Canadians with HAE types I, II, and normal levels of C1 inhibitor (nC1-INH). Materials and Methods: A 46-item patient survey evaluating clinical characteristics and burden of disease was developed and disseminated by the HAE patient organization Angio-oédeme héréditaire du Québec in Quebec, Canada, from May 2019 to February 2020. The survey received Research Review Board ethics approval. Results: In the 35 respondents, HAE type I was the most common (46%), followed by nC1-INH (43%). Female participants were significantly younger at first symptom presentation than males (p=0.04). Prior to diagnosis, 69% of participants underwent unnecessary treatments and procedures, with a 10-year delay between first symptoms and diagnosis. Before starting the current treatment, 42% of participants experienced weekly HAE attacks. Most participants identified experiencing attacks in the abdomen (89%), followed by the larynx (66%), feet (66%), hands (63%), and face (63%). Most attacks were severe or moderate, yet almost half of patients waited >1 hr before getting medical attention at their last emergency department (ED) visit. HAE was associated with decreased health-related quality of life, leading to significant functional impairment in personal and professional life. As compared to HAE type I/II, patients with HAE nC1-INH were treated more often with tranexamic acid for long-term prophylaxis, and their condition was less controlled, resulting in more attacks and ED visits. Conclusion: HAE manifests in this patient population as frequent moderate-to-severe attacks and a high disease burden; the HAE subtype may differentially affect care requirements. There is an urgent need for increased awareness and education on HAE among treating physicians.

Hereditary angioedema: do patients have a specific "digital fingerprint" in Danish registries?

INTRODUCTION: Hereditary angioedema (HAE) is a potentially life-threatening genetic disorder characterized by recurrent episodes of angioedema. From the onset of symptoms until diagnosis, patients often have several contacts with the healthcare system. It was hypothesized that a "digital fingerprint" of undiagnosed HAE patients could be identified in Danish registries. METHODS: This study compared patients with a control group of patients with a diagnosis of Quincke's edema (QE) or bee/wasp allergy because they could have phenotypic similarities. RESULTS: QE was the most common diagnosis code in the hospital sector among HAE patients before a specific diagnosis of HAE was established. HAE patients had been seen at the hospital on average once every other year before the diagnosis was established, and on average once during the year before the diagnosis was established. Many patients contacted a practicing dermatologist during the year before the diagnosis was established. CONCLUSIONS: HAE patients had several hospital contacts due to swelling attacks during the years before their diagnosis was established, and half of them consulted a dermatologist. It was not possible to identify a specific "digital fingerprint" in Danish registries regarding specific procedures or diagnoses distinguishing them from the control group. It is therefore recommended that hospitalized patients with angioedema of unknown cause be screened for HAE.

Repeated attacks of hereditary angioedema in pediatric female.

A 16-year-old female presented to an outpatient clinic with a 13-year history of recurrent episodes of abdominal pain, vomiting and mild cutaneous swelling, either spontaneously or following minor trauma. The episodes occurred every 1-2 months. There was no family history of a similar complaint or hereditary angio-oedema (HAE). At the age of 16, evaluation confirmed the diagnosis of HAE type II, characterised by low C4 levels and reduced C1 esterase inhibitor function. The patient was prescribed tranexamic acid 1 g twice daily as well as C1 esterase inhibitor used as rescue medication during symptomatic episodes. This case report emphasises the importance of considering a diagnosis of HAE in patients with recurrent, unexplained abdominal pain, even in the absence of a positive family history of HAE.Abbreviations: ANA Antinuclear antibodies; C1-INH C1-inhibitor; CBC Complete blood count; FMF Familial Mediterranean fever; HAE Hereditary angioedema; IBD Inflammatory bowel diseases; SDP Solvent detergent-treated plasma; SLE Lupus erythematosus.

Transmission patterns of C1-INH deficiency hereditary angioedema favors a wild-type male offspring: Our experience at Chandigarh, India.

BACKGROUND: Deficiency of C1-inhibitor (C1-INH) protein, caused by pathogenic variants in the Serpin family G member 1 (SERPING1) gene, is the commonest pathophysiological abnormality (in ∼95 % cases) in patients with hereditary angioedema (HAE). C1-INH protein provides negative control over kallikrein-kinin system (KKS). Although the inheritance of the HAE-C1-INH is autosomal dominant, female predominance has often been observed in patients with HAE. OBJECTIVE: To analyze the risk of transmission of SERPING1 gene variant from father or mother to their offspring. METHODS: Pedigree charts of 42 families with a confirmed diagnosis of HAE-C1-INH and a pathogenic variant in the SERPING1 gene were analysed. Patients with HAE who had had at least one child were included for analyses to assess the risk of transmission from the father or mother to their offspring. RESULTS: Overall, 49 % (189/385) of all offspring inherited the genetic defect. In the subgroup analyses, 54.8 % (90/164) female offspring and 44.8 % (99/221; p < 0.02) male offspring inherited the genetic defect. Inheritance of the genetic defect was significantly lower in male offspring. Fathers with SERPING1 gene variant had a statistically significant skewed transmission of the wild type to the male offspring as compared to the variant (57.8 % wild type vs. 42.1 % variant; p < 0.02), whereas no statistically significant difference was found when a father transmitted the variant to a female offspring. Mothers with SERPING1 gene variant had no statistically significant difference in variant transmission to male or female offsprings. CONCLUSION: Results of the study suggest that the transmission pattern of SERPING1 gene variant favours the transmission of wild-type alleles in males, especially when the father is the carrier; hence, overall, fewer males and more female offspring inherited the variant. This could be because of a selection of wild-type male sperms during spermatogenesis, as the KLK system has been reported to play a crucial role in the regulation of spermatogenesis. Although, a similar pattern was observed in the maternal transmission of the SERPING1 gene variant; the difference was not statistically significant, likely because of a small sample size.

Berotralstat in hereditary angioedema due to C1 inhibitor deficiency: first real-world evidence from a Canadian center.

Background: Hereditary angioedema due to C1 inhibitor deficiency is a rare genetic condition that causes recurrent swelling with consequent functional impairment and decreased quality of life. Long-term prophylaxis (LTP) to prevent angioedema episodes is a key component of disease management. Berotralstat, an oral, once-daily plasma kallikrein inhibitor, was approved for LTP by Health Canada in 2022. Methods: We conducted a retrospective, real-world study investigating the effectiveness and adverse effects of berotralstat. Data on angioedema frequency, disease control, and adverse events were tabulated. Patient satisfaction with treatment was scored on a 5-point Likert scale, with 1 representing very unsatisfied and 5 representing very satisfied with therapy. Results: From June, 2022 and May, 2023, 8 patients with HAE type 1 or type 2 received berotralstat. Effectiveness data were available for 7 patients who continued the drug for at least 3 months, 4 of whom switched to berotralstat from plasma-derived C1 inhibitor LTP. In these 7 patients, the average number of attacks per month decreased from 3.3 to 1.6 (p<0.05), representing a ~52% reduction in attack frequency. Median angioedema control test score numerically improved from 8 to 13 (p=0.0781). Of the 8 patients who received berotralstat, 3 reported no adverse effects and 5 experienced gastrointestinal side effects, which were mild and transient in 3 and led to discontinuation in 1. Average treatment satisfaction was between satisfied and very satisfied at 4.3. Conclusion: Berotralstat is an effective agent for long-term prophylaxis in HAE. Most patients experienced no adverse effects or mild, transient gastrointestinal symptoms.

Vision loss due to atypical bilateral edema of the optic nerve in a patient with hereditary angioedema: A case report.

PURPOSE: To describe a rare case of vision loss due to bilateral edema of the optic nerve in a patient with Hereditary Angioedema, treated with prophylactic C1-esterase inhibitor. METHODS: A 60-year-old Caucasian male affected by Hereditary Angioedema with unknown genetic defect (HAE- UNK) was admitted to our hospital presenting bilateral vision loss (best corrected visual acuity of 20/32 in the right eye and hand motion in the left eye) during an HAE attack. Intravenous administration of C1- esterase inhibitor (C1-INH, 1500 IU, Berinert, CSL Behring) determined the resolution of facial and periorbital swelling, however visual impairment persisted, in contrast with previous attacks experienced by the patient. Fundus examination revealed a vital optic disc without papilledema in both eyes. Magnetic resonance imaging (MRI) of the head and orbits showed bilateral edema of the optic nerve sheath. Treatment with intravenous and oral steroids was ineffective. Subsequently, a prophylactic treatment strategy with subcutaneous C1-esterase inhibitor was started (7000 IU every four days). RESULTS: Complete regression of edema of the optic nerves was observed by imaging at two months of follow-up after chronic treatment with C1-esterase inhibitor (7000 IU every four days). Complete restoration of visual acuity was achieved (BCVA 20/20 in both eyes) and multimodal imaging of the optic nerves demonstrated the absence of anatomical and functional damage. CONCLUSION: Patients affected by HAE may show atypical presentation with edema of the optic nerves without involvement of the optic nerve head. They may significantly benefit from prophylactic and chronic treatment with C1-esterase inhibitor.

Delay in diagnosis is the most important proximate reason for mortality in hereditary angio-oedema: our experience at Chandigarh, India.

BACKGROUND: Hereditary angio-oedema (HAE) is a rare autosomal dominant disorder characterized clinically by recurrent episodes of nonpruritic subcutaneous and/or submucosal oedema. Laryngeal oedema is the commonest cause of mortality in patients with HAE. Prior to the availability of first-line treatment options for the management of HAE, mortality was as high as 30%. Mortality has significantly declined in countries where first-line treatment options are available and patients can access these therapies. There is a paucity of literature on the outcomes of patients with HAE in developing countries where availability of and access to first-line treatment options are still a challenge. OBJECTIVES: To report our experience on mortality in patients with HAE and to report factors associated with the death of these patients. METHODS: We carried out a record review of all patients diagnosed with HAE between January 1996 and August 2022. Families with HAE who had reported the death of at least one family member/relative from laryngeal oedema were studied in detail. RESULTS: Of the 65 families (170 patients) registered in the clinic, 16 families reported the death of at least one family member/relative from laryngeal oedema (total of 36 deaths). Of these 16 families, 14 reported that 1 or more family members had experienced at least 1 attack of laryngeal oedema. One patient died during follow-up when she was taking long-term prophylaxis with stanozolol and tranexamic acid, while the remaining 35 patients were not diagnosed with HAE at the time of their death. At the time of death of all 36 patients, at least 1 other family member had symptoms suggestive of HAE, but the diagnosis was not established for the family. CONCLUSIONS: To our knowledge, this is the largest single-centre cohort of patients with HAE in India reporting mortality data and factors associated with death in these families. The delay in diagnosis is the most important reason for mortality.

Clinical Evaluation of Pediatric Patients with Hereditary Angioedema.

Hereditary angioedema is a rare, potentially life-threatening disease. There is a lack of data describing the clinical course of hereditary angioedema (HAE) in children. We aimed to evaluate the clinical characteristics of pediatric patients with hereditary angioedema: The age of disease onset, age at diagnosis, the frequency of angioedema attacks, the total number of attacks before diagnosis, the regions where angioedema attacks were observed, accompanying abdominal pain, and serum levels of C4 and C1 esterase inhibitor were obtained and recorded. In addition, the results of SERPING1 (C1INH) gene sequence analysis of the patients in this group were also collected from medical records and recorded. While none of the patients reported a skin rash as a symptom of attack, there was formication observed in the region of angioedema in 46.9% (n = 15) of the patients and pruritus in 6.2% (n = 2) of the patients. At disease onset, the complaints of the patients regarding location of edema were on the hands of 32.3% (n = 10), on the feet of 9.7% (n = 3), on the faces of 25.7% (n = 8), and abdominal attacks in 32.3% of the patients (n = 10). Four different variants, one of which was novel, were detected in the SERPING1 gene in eight different families. The results of this study suggest that hereditary angioedema is diagnosed only when the patient requests examination following recurrent angioedema. Severe laryngeal edema attacks in patients without a diagnosis of HAE are fatal at a higher rate than attacks in patients with a diagnosis. Thus, awareness of the symptoms of HAE is necessary, and correct diagnosis is essential to proper treatment.

Uncovering the true burden of hereditary angioedema due to C1-inhibitor deficiency: A focus on the Asia-Pacific region.

Hereditary angioedema (HAE) due to C1-inhibitor deficiency or dysfunction is a rare genetic disorder that causes recurrent episodes of swelling in various parts of the body. Treatment goals of HAE aim to "normalize" life for all patients; however, lack of diagnostic facilities and limited access to effective treatment options in developing nations cause delays in diagnosis and place a significant burden on patients. In this review, we aim to highlight the burden of disease caused by C1-inhibitor HAE across the Asia-Pacific region, considering its epidemiology, morbidity and mortality, and socioeconomic and psychological impact. We also review the availability of guideline-recommended diagnostic facilities and treatments, and how patients are currently managed. Data were collected from published literature and HAE experts in the region, who provided information regarding diagnosis and management in their countries. Current practice was reviewed against international guidelines, as well as local guidelines/consensus used in Australia, Japan, and China. Suggestions are provided for improving the time to diagnosis in the region, increasing access to guideline-recommended treatments, and providing support to reduce the burden on patients and caregivers. There is an urgent need to improve HAE services and provide access to life-saving treatment in developing countries, and efforts should be made to increase awareness of guideline recommendations in high-income economies that do not currently provide long-term prophylactic treatments.

Universal Access to On-Demand Treatment of Patients with Hereditary Angioedema, the Chilean Experience.

Background: In Chile, patients with hereditary angioedema (HAE) type I and type II are protected under Ley Ricarte Soto (LRS), which guarantees access to on demand plasma-derived C1-INH (pdC1-INH) since 2018. We aimed to analyze the first 3 years of LRS. Methods: Review of the LRS database between 2018 and 2021. Results: During the study period, 154 patients were covered by LRS, with an estimated prevalence of HAE in Chile at 0.8:100,000 inhabitants. A delay in diagnosis of 22 years was noted, 50 patients received epinephrine during an attack before the diagnosis of HAE. Mean number of attacks per year was 8, with 50% of adults and 42% of children experiencing more than 1 attack per month. Conclusion: Disease awareness must improve to reduce the diagnostic delay of HAE. Long-term prophylactic medications should be included in LRS to treat patients with high attack rates and control the costs of frequent on-demand treatment with pdC1-INH.

Hereditary angioedema: Patient journey approach in Mexico.

Objective: To understand the patient's journey with HAE from symptom initiation to diagnosis, treatment allocation, follow-up, and the impact of the disease on their quality of life in Mexico. Methods: A survey was administered to the patients with HAE. Participants completed a questionnaire covering five domains: patient journey; effects on productivity, school performance and daily activities; quality of life; anxiety and depression. Responses were analyzed using descriptive statistics. Results: A total of 17 surveys were analyzed (15 women and 2 men, age range: 23-67 years). Type I HAE was most common (71%), normal C1 inhibitor HAE was 12% and 18% did not know their HAE type. The average disease evolution was 13.7 years and the time from symptom initiation to diagnosis was 20 years. 59% of patients knew of one or two treatments available, 12% knew 3 treatments and 18% were aware of 4 or more, 12% were not aware of any treatments. 53% had a job, 18% referred a severely anxious state, 41% were depressed and all patients referred some social impact due to HAE. Conclusions: There is a need to reinforce the knowledge of general practitioners on HAE to promote an earlier diagnosis and awareness of rare diseases and their impact on quality of life among the general population and promote the removal of barriers to treatment.

Objetivo: Conocer el seguimiento pacientes mexicanos con angioedema hereditario, desde el inicio de los síntomas hasta el diagnóstico, prescripción del tratamiento y seguimiento, y repercusión en la calidad de vida. Métodos: Estudio transversal, llevado a cabo a partir de la aplicación de una encuesta a pacientes con angioedema hereditario, que abarcó cinco ámbitos: seguimiento del paciente; afectación en la productividad, el rendimiento escolar y las actividades cotidianas; calidad de vida; ansiedad y depresión. Las respuestas se analizaron mediante estadística descriptiva. Resultados: Se analizaron 17 encuestas (15 mujeres y 2 hombres, rango de edad: 23-67 años). El angioedema hereditario tipo I fue el más frecuente (71%), el angioedema hereditario clásico con inhibidor de C1 fue del 12%; y el 18% no conocía su tipo de angioedema hereditario. La evolución media de la enfermedad fue del 13.7 años y el tiempo transcurrido desde el inicio de los síntomas hasta el diagnóstico fue de 20 años. El 59% de los pacientes conocía uno o dos tratamientos disponibles y el 12% no conocía ninguno. El 53% tenía trabajo, el 18% refería un estado de ansiedad grave, el 41% tenía depresión y todos referían algún efecto social debido al angioedema hereditario. Conclusiones: Es necesario reforzar los conocimientos de los médicos acerca del angioedema hereditario para establecer el diagnóstico temprano, el conocimiento de las enfermedades raras, su repercusión en la calidad de vida entre la población y eliminar los factores que entorpecen el tratamiento.

Pathogenic variant in SERPING1 gene causing autosomal dominant hereditary angioedema in early childhood.

A female in early childhood presented with 6 months of transient swelling of multiple areas of her body, often, but not always, associated with minor trauma. Labs drawn were significant for low C4, low CH50, low C1 esterase inhibitor (C1-INH) antigen and low C1-INH function, which is concerning for hereditary angioedema (HAE) with abnormal C1-INH. Genetic testing through the Invitae Hereditary Angioedema Panel revealed a variant in the SERPING1 gene, c.686-7C>G (Intronic), which was classified as a variant of unknown significance, but is likely pathogenic given patient's clinical presentation and recent functional proof of pathogenicity. HAE should be recognised in paediatric patients even without family history. Recognising the symptoms of HAE and confirming diagnosis in early childhood has become more important recently as the first prophylactic therapy, lanadelumab, was approved in February 2023 for long-term prophylaxis in early childhood, which can significantly improve morbidity and quality of life.

[Facial swelling due to angioedema: often mast cell mediated, but not always]. / Gelaatszwellingen door angio-oedeem.

Most cases of angioedema are mast cell mediated. We present three patients with angioedema, who were admitted to our emergency room or outpatient clinic. One of them did have mast cell mediated angioedema, despite insufficient response to initial antihistamine treatment. The other patients had more rare cases of angioedema, i.e. hereditary angioedema with C1-inhibitor deficiency and angiotensin converting enzyme inhibitor associated angioedema. We discuss similarities and differences in symptoms, diagnosis and treatment between these causes of angioedema. We recommend keeping the differential diagnosis of angioedema in mind when a patient with angioedema is presented, including rarer pathophysiological explanations.

Acquired Angioedema Due to C1-Inhibitor Deficiency (AAE-C1-INH)-A Bicenter Retrospective Study on Diagnosis, Course, and Therapy.

BACKGROUND: Acquired angioedema with C1-inhibitor deficiency (AAE-C1-INH) is a rare condition resembling hereditary angioedema (HAE), but with late onset and low C1-inhibitor (C1-INH) due to consumption potentially caused by autoimmune diseases and mainly lymphatic malignancies. Being about 10-fold rarer than HAE, there is limited knowledge and no licensed therapy. OBJECTIVE: To report clinical and biological data from a newly described population of 20 patients with AAE-C1-INH assessing diagnostic delay, AAE-C1-INH:HAE-ratio, underlying conditions, and therapeutic management in Germany. METHODS: Retrospective data analysis of 20 patients from 2 angioedema centers in southern Germany. RESULTS: Median age at symptoms' onset was 64 years (60% females), with predominant swellings of the face (85%) and low levels for C1-INH in almost all patients. The ratio AAE-C1-INH:HAE was 1:9.7. From symptoms' onset to diagnosis of AAE-C1-INH, the median delay was 7.5 months, and between AAE-C1-INH symptoms' onset and diagnosis of the underlying hematological condition (n = 9) it was 4 months (median). Four patients had a history of solid neoplasm, 1 had a papillary thyroid carcinoma as the only potential cause for AAE-C1-INH, with treatment of the malignancy resulting in resolution of AAE-C1-INH. All the symptomatic patients were treated with off-label on-demand icatibant subcutaneously or C1-INH concentrate intravenously, and 6 severely affected patients needed off-label long-term prophylaxis with good symptom control. CONCLUSIONS: AAE-C1-INH is characterized by late-onset swellings mainly involving the face and low C1-INH levels. Diagnostic delay for AAE-C1-INH is further decreasing despite being about 10-fold rarer than HAE. Patients severely affected without underlying condition or no indication for treatment could benefit from off-label therapy.