[en] Association of acquired autoimmune angioneurotic edema with other diseases is increasing. However, the precise mechanism by which antibodies to C1-esterase inhibitor (C1-INH) are produced, is not elucidated. We describe a patient with IgA antibodies against C1-INH without other autoimmune markers. Our patient had gastritis and Helicobacter pylori infection, proven by biopsy. This case suggests that H. pylori infection can act as triggering factor for acquired autoimmune angioneurotic edema.