Angioedema without urticaria may be due to congenital C1 esterase inhibitor deficiency [type I hereditary angioedema (HAE)], dysfunctional C1 esterase inhibitor (type II HAE) and hereditary angioedema with normal C1 inhibitor and mutations in the factor XII gene [1, 3, 4]. This evidence concerns the gene C1S and hereditary angioedema.