SERPING1 and angioedema: Most cases of recurrent angioedema are either mast cell‐mediated (e.g. in patients with chronic urticaria) or bradykinin‐mediated (e.g. in patients with hereditary angioedema due to C1‐inhibitor deficiency [HAE‐C1INH] or acquired C1‐inhibitor deficiency [AAE‐C1INH]).