Different rates of autoreactivity in patients with recurrent idiopathic angioedema associated or not with wheals.

BACKGROUND The pathophysiology and triggers of idiopathic nonhistaminergic angioedema are unclear. This study aimed to assess autoreactivity in recurrent idiopathic angioedema associated or not with wheals. METHODS The study population comprised 19 patients with recurrent idiopathic nonhistaminergic angioedema without wheals, 38 patients with angioedema and chronic urticaria (CU), and 52 patients with CU without angioedema. Twenty healthy individuals served as controls. Autoreactivity was evaluated in vivo using the autologous serum skin test (ASST) and in vitro by measuring serum-induced basophil histamine release (BHR). RESULTS ASST results were negative in all patients with idiopathic angioedema without wheals and in healthy controls and positive in 29 of the 38 patients with angioedema and CU (76.3%) and in 26 of the 52 patients with CU without angioedema (50%) (P < .0001 for both CU groups). BHR was negative in the healthy controls and positive in 2 of the 19 patients with idiopathic angioedema without wheals (10.5%), in 18 of the 38 patients with angioedema and CU (47.3%) (P < .0001), and in 11 of the 52 patients with CU without angioedema (21.1%) (P < .03). CONCLUSION The different rates of autoreactivity observed in patients with idiopathic nonhistaminergic angioedema without wheals and in patients with CU either with or without angioedema suggest that these disorders have a different pathophysiology. The failure to detect circulating vasoactive factors and histamine-releasing autoantibodies explains why H1 antihistamines are scarcely effective in most patients with idiopathic angioedema without wheals. However, they represent the cornerstone of CU treatment.