Hypersensitivity vasculitis associated with leuprolide (Lupron).

Leuprolide (Lupron) is a synthetic analog of naturally occurring gonadotropin-releasing hormone (GnRH). Leuprolide is used as a hormonal antagonist in the treatment of advanced prostatic cancer, and as hormonal therapy in the treatment of endometriosis. Off-label, it is also used in premenopausal or perimenopausal women with hormone-responsive breast cancer for the purpose of ovarian ablation. Ever since its FDA approval in 1985, many adverse reactions have been reported in association with leuprolide ranging from local skin irritation to severe anaphylactoid reactions. In this case report, we present a case of hypersensitivity vasculitis (serum sickness) in a patient who received leuprolide for his prostate cancer. Serum sickness has never been reported as a side-effect of leuprolide. Our case is the first case of serum sickness associated with leuprolide. We emphasize that physicians using leuprolide should be wary of signs and symptoms of hypersensitivity vasculitis or serum sickness.