Progesterone Sensitivity as a Cause of Recurrent Anaphylaxis

ANAPHYLACTIC or anaphylactoid attacks usually occur in immediate response to a specific inciting agent or event. Patients with recurring anaphylaxis in whom there is no evidence of an external cause are classified as having recurrent idiopathic anaphylaxis.¹,² One such patient had weekly life-threatening anaphylactic episodes that were partly controlled with intensive medical therapy combined with tracheal fenestration; however, spontaneous remission of the attacks during lactation led to the suspicion of sensitivity to sex hormones. Three clinical observations confirmed this suspicion: provocative challenges with minute quantities of progesterone caused an anaphylactic event, inhibition of pituitary gonadotropin release by luteinizing hormone-releasing hormone.