Hereditary angioedema type III is characterized primarily by skin swellings (predominantly facial) and abdominal attacks. Additional symptoms that may occur are tongue swellings, laryngeal edemas and swellings of the soft palate. Affected individuals are predominantly women, though men can be affected, typically at a later age of onset and with less frequency and severity of attacks. Factors that can influence the onset and frequency of angioedemic attacks include trauma and increased estrogen levels. Nearly 60% of women experienced onset of symptoms after initiation of oral contraceptives or during the first pregnancy :Features that distinguish HAE type III from types I and II include: presence of normal C1 inhibitor activity levels, average later age of onset (typically in the 2nd decade of life), predominance of facial swelling as compared to swellings of the extremities and sex bias.