Snapshot A 16-year-old boy presents to the emergency department with increased difficulty breathing and swelling of the lips and tongue. The patient reports colicky abdominal pain and denies any food or medication allergies. He does state that yesterday he had a minor dental procedure and that this morning he experiened "flu-like" symptoms. Family history is significant for the mother having these episodes of swelling that are typically self-limiting. In the emergency department he is treated for anaphylaxis, but this did not improve his symptoms. Laboratory testing is significant for decreased C1 inhibitor, C4, and C2 levels. After appropriate management, the patient is started on long-term prophylaxis for his genetic condition. (Hereditary angioedema) Introduction Mechanism of action pituitary-ovarian axis suppressant possibly due to inhibiting pituitary gonadotropin output as well as sex hormone receptor interaction affecting metabolism of sex steroids increases serum C1 esterase inhibitor leading to increased C4 concentration Clinical use endometriosis hereditary angioedema fibrocystic breast disease Toxicity weight gain acne plus other androgenic effects