Patients with prior evidence of an anaphylactoid reaction to contrast media should receive appropri- ate steroid and antihistamine prophylaxis before repeat contrast administration.252,284 286 (Level of Evidence: B) Class III: NO BENEFIT 1. In patients with a prior history of allergic reactions to shellfish or seafood, anaphylactoid prophylaxis for contrast reaction is not beneficial.287 289 (Level of Evidence: C) The incidence of anaphylactoid reactions to contrast media is 1%, and the incidence of severe reactions may be as low as 0.04%.284 Limited data suggest that in patients with a history of prior anaphylactoid reaction, the recurrence rate without prophylaxis is in the range of 16% to 44%.341 Adequate pretreatment of patients with prior anaphylactoid reactions reduces the recurrence rate to close to zero.284 286 A regimen of 50 mg of prednisone administered 13 hours, 7 hours, and 1 hour before the procedure (as well as 50 mg of diphenhy- dramine 1 hour before the procedure) has been shown to reduce the risk of recurrent anaphylactoid reaction.286 In practice, a regimen of 60 mg of prednisone the night before and morning of the procedure (as well as 50 mg of diphen- hydramine 1 hour before the procedure) is often used.252 There are minimal data on the pretreatment of patients undergoing emergency PCI.342 One group has suggested IV steroids (eg, 80 mg to 125 mg of methylprednisolone, 100 mg of hydrocortisone sodium succinate), as well as oral or IV diphenhydramine and possible IV cimetidine.284 For a more detailed discussion of issues related to contrast-induced anaphylactoid reactions, the reader is referred to several dedicated discussions on contrast agents.284,341 There are no data to suggest that those patients with seafood or shellfish allergies are at risk for an anaphylactoid reaction from exposure to contrast media. 