Severe anaphylactoid reaction to radiographic contrast media. Recurrences despites premedication with diphenhydramine and prednisone.

Patients with a history of anaphylactoid reaction to radiographic contrast medium (RCM) are at increased risk for subsequent reaction. To date, 275 of these high-risk patients have been studied with use of prophylactic pretreatment with diphenhydramine hydrochloride or prednisone or both without a single severe anaphylactoid reaction on readministration of RCM. This report describes a patient who received pretreatment as described in the literature but suffered a life-threatening anaphylactoid reaction on readministration of RCM. Premedication does not eliminate the possiblity of a fatal reaction on readministration of RCM.