The Complex Interaction Between Polycystic Ovary Syndrome and Hereditary Angioedema: Case Reports and Review of the Literature.

Importance: Hereditary angioedema (HAE) is a rare but severe disease, with high risk of death, and attacks have been associated to high estrogen levels. Polycystic ovary syndrome (PCOS) is a common hyperandrogenic condition, which is frequently treated with combined oral contraceptives.

Objective: The aim of this study was to describe 2 clinical cases of young women diagnosed as having PCOS who developed HAE attacks after the introduction of combined estrogen-progestin pills to treat PCOS symptoms.

Evidence Acquisition: Literature review of sex hormones' role in genesis of HAE attacks and possible mechanisms involved.

Results: In the cases reported, after initiation of combined contraceptives, patients presented with facial swelling with airway involvement (laryngeal edema) and abdominal pain. They had a familial history of angioedema and normal C1 inhibitor (C1-INH) levels, leading to the diagnosis of HAE with normal C1-INH (HAEnC1-INH) or HAE type III. After suspension of exogenous estrogen, patients remained asymptomatic from HAE.

Conclusions and Relevance: HAEnC1-INH is an estrogen-dependent form of HAE. It is well established that exogenous estrogen triggers attacks of all types of HAE. However, this is the first description of the association between PCOS and HAE, in which PCOS could be masking HAE symptoms. We propose that PCOS might have a protective role regarding HAE attacks, because of its particular hormonal features, that is, hyperandrogenism and relative stable levels of estradiol. The use of combined estrogen-progestin compounds in women with PCOS and HAE must be avoided, and treatment must be individualized.