- To the Editor: Anaphylactic reactions in patients receiving pulsatile gonadotropin-releasing hormone (GnRH) are rare.1 We describe a patient who had such a reaction when given GnRH intravenously after having received pulsatile subcutaneous GnRH therapy for 10 weeks. The patient was a 31-year-old man with infertility due to severe oligospermia. His sexual development and physical examination were normal. The plasma follicle-stimulating hormone, luteinizing hormone, and testosterone concentrations were 8 mIU per milliliter, 10 mIU per milliliter, and 450 ng per deciliter (15.6 nmol per liter), respectively. The patient underwent an intravenous GnRH stimulation test with 100 μg of GnRH and then . . .