The Role of Mast Cells Mediators in Angioedema Without Wheals

Hypersensitivity reactions amongst Hungarian Patients with Hereditary Angioedema due to C1-Inhibitor Deficiency

Background

In hereditary angioedema (HAE) due to C1-inhibitor deficiency (C1-INH-HAE), bradykinin-mediated submucosal and/or subcutaneous angioedema dominates the clinical picture. The deficiency of C1-inhibitor can lead to the over-activation of the complement system. Complement plays an important role in all types of hypersensitivity reactions. On the other hand, during the degranulation of mast cells, heparin is also released amongst other substances. Heparin can activate the plasma kinin-kallikrein system, leading to bradykinin generation. These observations suggest a possible connection between C1-INH-HAE and mast cell-mediated hypersensitivity reactions.

Objective

To assess the occurrence of hypersensitivity reactions in the Hungarian C1-INH-HAE population.

Methods

Patients filled out a questionnaire of 112 questions, either online or on paper. The questions were about hypersensitivity and C1-INH-HAE symptoms, the relation between these 2, general health, and demographic data. The study protocol was approved by the institutional review board of Semmelweis University, Budapest, and informed consent was obtained from the participants.

Results

One hundred and six patients (64 female, 42 male, median age 46 years) responded, with 63.2% having hypersensitivity. Hypersensitivity was provoked by pollen in 25.5% of patients, by contact sensitivity in 22.6%, by food in 21.7%, by insect sting in 19.8%, by pet in 15.1%, by drug in 14.2%, by dust mite in 5.7%, and by mold in 1.9%. In 11 patients, hypersensitivity symptoms appeared after the diagnosis of C1-INH-HAE. Six hypersensitive patients experienced improvement in their symptoms; 42 remained the same, but none experienced worsening after the diagnosis of C1-INH-HAE. In 7.8% of the hypersensitive patients, a C1-INH-HAE attack worsened the hypersensitivity symptoms, while 15.7% of the hypersensitive patients experienced a C1-INH-HAE attack provoked by contact with the provoking factor.

Conclusion

While 63.2% of our C1-INH-HAE patients have reported hypersensitivity symptoms, Eurostat's latest data puts the prevalence of self-reported allergies in Hungary at 19.3%. Since in our experience most Hungarian patients report hypersensitivity reactions as allergies, this may support a possible connection between the 2 diseases, but further molecular studies are needed.

Pathophysiology of bradykinin and histamine mediated angioedema

Angioedema is characterized by swelling localized to the subcutaneous and submucosal tissues. This review provides an overview of angioedema, including the different types, triggers, and underlying pathophysiologic mechanisms. Hereditary and acquired angioedema are caused by dysregulation of the complement and kinin pathways. In contrast, drug-induced and allergic angioedema involve the activation of the immune system and release of vasoactive mediators. Recent advances in the understanding of the pathophysiology of angioedema have led to the development of targeted therapies, such as monoclonal antibodies, bradykinin receptor antagonists, and complement inhibitors, which promise to improve clinical outcomes in patients with this challenging condition. To accurately diagnose and manage angioedema, an understanding of this condition's complex and varied pathophysiology is both necessary and critical.

Angioedema without urticaria after recent initiation of celecoxib

Angioedema is potentially life-threating swelling of integument and mucosa that has multiple potential aetiologies with varying mechanisms. Drug-induced angioedema is often easily correlated with the offending agent and can be prevented with discontinuation of the medication. Many medications have now been implicated in drug-induced angioedema but the two most common are ACE inhibitors and non-steroidal anti-inflammatory drugs (NSAIDs). This case highlights severe angioedema secondary to celecoxib and reviews varying aetiologies of angioedema and NSAID hypersensitivity reactions.

Classification and Treatment of Angioedema without Wheals: A Spanish Delphi Consensus

INTRODUCTION

Problems in the definition and classification of angioedema, leading to difficulties in its diagnosis and treatment, have been identified; therefore, an improvement in the current classification of angioedema is required.

OBJECTIVE

The aim of this study was to propose a practical classification of angioedema without wheals that helps to establish a differential diagnosis and take appropriate therapeutic decisions.

METHODS

An initial proposal of classification of angioedema without wheals was agreed by a scientific committee of experts and was subsequently validated by a panel of experts by means of consensus based on the Delphi methodology. Forty-five items on the classification, diagnosis, and treatment of angioedema without wheals were proposed for the survey.

RESULTS

Most items (93.8%) were agreed after two rounds. All panelists agreed with the proposed classification, as well as with most of the clinical and treatment characteristics. The angioedema without wheals classification established three groups: histamine-mediated, bradykinin-mediated, and unknown mechanism angioedema. The clinical characteristics of the proposed types of angioedema were also agreed, except for the allergic histamine-mediated and unknown mechanism angioedema, which generated debate. Regarding treatments, although there was broad agreement with the proposed items, a lack of knowledge about some treatments in this pathology was observed.

CONCLUSION

The proposed classification of angioedema without wheals was accepted with a high degree of agreement; however, knowledge of available treatments needs to be increased and the definition of angioedema of unknown mechanism needs to be improved.