Which allergy should a nurse identify in a client scheduled for excretory urography?

The correct choice highlights the importance of recognizing allergies to seafood in clients scheduled for excretory urography, primarily due to the use of contrast media that may contain iodine. Many contrast agents used in radiological procedures are iodine-based and can cause allergic reactions in individuals who are allergic to seafood, particularly shellfish. This happens because shellfish allergies are often related to iodine sensitivities, given that some shellfish contain protein structures similar to those found in iodine-based contrast media.

In contrast, while other allergies like latex might be relevant in a healthcare setting, they do not have the same direct connection to the contrast used in excretory urography. Dairy and eggs are also unrelated to the concerns around iodine allergy and contrast material used in such imaging procedures. Recognizing the client's allergy history, especially to seafood, is crucial for preventing potential serious allergic reactions during the examination process.