Table 1.

Classification of angioedema

I. Idiopathic

II. Medications (allergic or non-allergic)  ACE inhibitors: activated bradykinin ↑  NSAIDs: COX 1 inhibition → leukotrienes ↑

III. Allergen-induced (foods, etc.): histamine ↑ (IgE mediated)

IV. Physically induced (cold, pressure, vibration, ultraviolet, etc.): histamine ↑ (direct)

V. Deficiency or inactivation of C1-INH : uncontrolled complement activation → bradykinin ↑  1. HAE   a. HAE type 1 (80–85 %): decreased level of C1-INH   b. HAE type 2 (10–15 %): normal or high levels of dysfunctional C1-NIH  2. AAE with C1-INH deficiency   a. AAE type 1 associated mainly with lymphoproliferative disorders (e.g., lymphoma)   b. AAE type 2 associated with anti-C1-INH autoantibodies (e.g., autoimmune diseases)

VI. HAE type 3 (rare): normal or slightly low C1-INH level with normal function  1. Coagulation factor XII gene mutation (HAE-FXII): activated factor XII ↑ → bradykinin ↑  2. HAE-unknown

ACE angiotensin-converting enzyme, NSAIDs nonsteroidal anti-inflammatory drugs, COX1 cyclooxygenase 1, C1-INH complement 1 esterase inhibitor, HAE hereditary angioedema, AAE acquired angioedema