What is a sign of a mild allergic reaction to contrast media?

A sign of a mild allergic reaction to contrast media is urticaria, also known as hives. Urticaria is characterized by raised, itchy welts on the skin that result from the release of histamines during an allergic response. This type of reaction is considered mild because it typically does not lead to more severe symptoms such as respiratory distress or cardiovascular issues.

In the context of allergic reactions, urticaria is a classic indicator. It specifically reflects the body's localized response to the allergen present in the contrast media. Mild reactions like urticaria are generally manageable and may resolve with antihistamines or other symptomatic treatments.

Others in the list, like a rash, nausea, and vomiting, may indicate different types of reactions or side effects that are not exclusively linked to allergic reactions. While they can occur in the context of various conditions or reactions, urticaria distinctly represents a mild allergic response to contrast media.