Urticaria and Angioedema

Pathophysiology of Angioedema

Angioedema is a condition characterized by deep dermal or submucosal swelling due to increased vascular permeability. This swelling occurs due to various triggers, including allergic reactions, genetic predispositions, or drug-induced mechanisms.

Causes and Mechanisms

• Histamine-Mediated Angioedema: Resulting from mast cell degranulation, often linked to allergies or anaphylaxis.
• Bradykinin-Mediated Angioedema: Occurs due to excessive bradykinin, commonly associated with hereditary angioedema or ACE inhibitor-induced angioedema.
• Idiopathic Angioedema: Cases where no definitive cause is identified.

Clinical Presentation

Patients typically exhibit non-pitting swelling in the face, extremities, or gastrointestinal tract. In severe cases, airway involvement may lead to respiratory distress.

Diagnostic Approach

Diagnosis involves clinical evaluation, laboratory tests to assess complement proteins (C1-INH levels), and exclusion of other potential causes.

Treatment and Management

• Antihistamines and corticosteroids for histamine-mediated cases.
• Bradykinin-targeted therapy such as C1-INH concentrate for hereditary angioedema.
• Supportive care and avoidance of known triggers.